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(Topic ID: 129690)

Eight Ball Deluxe No Sound


By policano

5 years ago



Topic Stats

  • 52 posts
  • 10 Pinsiders participating
  • Latest reply 3 years ago by Jesterfunhouse
  • Topic is favorited by 5 Pinsiders

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There are 52 posts in this topic. You are on page 1 of 2.
#1 5 years ago

Picked up an EBD last night with no sound. Purchased a CAP kit but upon looking into it more I have NO lED light on or flashing when the game boots. repined J1 and TP2 has .5 not 5 VDC (this looks to be GI power) however I have GI lights in the head. Im stumped.

#3 5 years ago

I wish I could help buddy. When you get it working I will come play it and drop a huge score on it...but I don't have much in the fix it department.

Someone help this guy!

#4 5 years ago

Thanks John! We did do the CAP Kit however as expected, no LED light. It has to be related to the .5 VDC instead of 5 VDC.

#5 5 years ago

Tony:

When I got mine home I had the same thing. I'm not sure the connector number, but it was on the top right of the power board. It has something like 24 pins? That fixed mine along with an occasional reset issue. Hope this helps!!

Brian

#6 5 years ago

I just pulled every wire and punched them down again...

#7 5 years ago

you da man Brian! thanks! You were gonna me be my call for help tomorrow

#8 5 years ago

Got the Voice working now and some noises gonna mess with it some more. Thanks again buddy!

#9 5 years ago

We are out of energy to continue tonight. 6:10PM-5:30AM and we have A LOT MORE TO DO!

#10 5 years ago

Caps are big as with any board issues but with the old Ballys it's usually in the connectors. I re-pin and re-plug as a matter of course and it solves 95% of any problems. I currently have all of the sounds but no voice.

#11 5 years ago

Buy a capacitor kit and replace all caps, replace the micro pots for sound and speech, replace the main pot inside the coin door and validate continuity from there to the speakers and to the soundboard, test the board with a new speaker and test the speaker on another device such as a home stereo, buy molex connectors and crimp terminals to redo the connectors to the board.

#12 5 years ago

I have narrowed my problem down to the J3 connector on the driver board. Trying to figure out what wire on J3 is powering the S&T board? I don't seem to understand the schematics. I ordered replacement connectors from Great Plains however the site is closed until later this week. Just trying to find some answers so I can ensure my S&T board is working correctly. When I fiddle with the wires I can get it to work with sound and voice. I don't however have any background music.

Any help would be greatly appreciated.

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#13 5 years ago

I have always had to replace the small pots on the sound board to get the sound to work right (thankfully they are cheap and I bought a bunch a while ago). I have never had to replace the large pot on the coin door yet.

The cap kits are helpful for a board that seems like it should work but will not, but I have only had to do it on one pin so far. Generally the caps have been good for me on my pins, even though they are very old and are well past their expected life.

I have never had to repin/replug a sound board yet. Just resetting all of the connectors fixed any problems. I think it really helps that the sound board is not using much power, so the pins don't tend to get burned up.

#14 5 years ago

I know mine lies in the connector from the Driver board as I mess with the wires I can get it to work. I just am having trouble tracing what wire is powering the S&T board.

#15 5 years ago

Are you getting the flash + 5 blinks on the LED?

#16 5 years ago

No background music could be a setting on the rom. Have you checked to see what setting #18 is set to? 00, 01, and 02 do not play the background sounds. 03 does.

Does the s&t power off when you wiggle j3? Or does the sound just go in and out?

#17 5 years ago

thanks for the replies.

Quoted from Mk1Mod0:

Are you getting the flash + 5 blinks on the LED?

No flashes unless I mess with the connectors on driver board. Does do 5 flashes when I have power.

Quoted from knockerlover:

No background music could be a setting on the rom. Have you checked to see what setting #18 is set to? 00, 01, and 02 do not play the background sounds. 03 does.
Does the s&t power off when you wiggle j3? Or does the sound just go in and out?

I will check that, I haven't messed with any of those settings yet. It does power off the S&T board completely and back on when I continue messing with it.

#18 5 years ago

The S&T board is AI14 in the schems. It's J1 has several inputs from J3 on the driver board (A3). A3J3-16, 20, 5 and 23. But, something to consider A3J3 also has many inputs from the power board in the bottom of the cabinet (A2). It may be losing power from there instead of not sending it to the S&T.

My first inclination would be to repin that connector, then check and resolder if necessary the pins at J3 on the A3 driver board.

#19 5 years ago

Thanks so much! I will start with them. I don't believe its from the cab as when I mess with the connector on the Driver board is when I can get it to work

#20 5 years ago

We eliminated the connector and still have no power on the S&T board. We have no voltage on TP2 on the S&T board.

#21 5 years ago

This is what we have when testing the connector on J1 S&T:
A3J3-5 TO S&TJ1-9 (44 vdc)
A3J3-16 TO S&TJ1-5 (5 vdc)
A3J3-20 TO S&TJ1-6 (.05 vdc)
A3J3-23 TO S&TJ1-15 (-08 vdc)

#22 5 years ago

Well after having the game on for a few all the inserts stopped working, no power to displays, and now nothing works. I am beginning to hate this old game.

#23 5 years ago

I did notice when I turn on the game the scores and inserts do briefly come on.

#24 5 years ago
Quoted from policano:

We eliminated the connector and still have no power on the S&T board. We have no voltage on TP2 on the S&T board.

What do you mean by eliminated?

#25 5 years ago

Sorry, bad choice of wording. We were able to replace the connector. We took pictures of the existing and also followed the manual. It was late last night. I was trying to say we eliminated the problem lol

#26 5 years ago

My guess is that nothing powered now, means a blown fuse on the power driver board, or a problem at the bridge rectifier board.

For your original problem of sound, like others posted, its likely connectors. My personal experience with my EBD is connectors and one bad board too far gone to mess with. I did a repin kit on the MPU connectors http://www.marcospecialties.com/pinball-parts/CKBLY-MPU, and I repined the power connector at A3j3 - fixed the problem with intermittent S&T. I also had to replace the molex to the aux light board.

Other odd voltages can sometimes be at the rectifier board. Check voltages at AS-2518-54. Replaced those connectors as well. Examined my BR board and found a trace had burned through - probably previous owner jumped a fuse, and melted the trace.

I have usually been able to solve most of my Bally SS game problems with connectors.

Then again, sometimes I just punt and get a new board. EBD was one of those times. The game is a long term keeper so bought a new $100 rectifier board AS-2518-54 See specs @ http://www.rottendog.us/distributor.html. I bought from Marco Specialties http://www.marcospecialties.com/pinball-parts/AS-2518-54 (about $99 though)

I've also purchased MPU, Light and driver boards from www.allteksystems.com for other Bally's - if you are not into changing scr's or tip's - (Alltek now has aux light board too AS-2518-52 for EBD - Alltek boards have "Ultimate" in the title).

#27 5 years ago

Can you post a pic of the rectifier board and the a3j3 connector?

#28 5 years ago

unregulated 12v powers the amplifiers and the 5v regulator on a squawk and talk board. GI is used to create a negative -5v that the speech chip needs.

Repin driver j3 both sides. That sends the logic power to all your boards. It has to be solid or your game will not work.

#29 5 years ago

when I get home I can get pics. when you turn on the game I see the orange on the displays at the bottom of the displays and then the digits and the inserts briefly come on and the drops no longer reset when power up.

#30 5 years ago

Below is good to have printed for reference. My favorite explanation of Bally late 70's early 80's SS game workings. I learned a lot of stuff from this, and summarized how I used it in my prior post. Its the power flow at which boards, used for boot of the MPU, and how to test the parts, and trace the issues of no/low/high power. Somebody shared this with me years ago, I think Clay Herrill is the original source, so credit to him (I think that's correct on who authored this?).

+++++++++++++++
All the boards in the Bally games have TP "test points". These are points where the voltages can be tested for proper levels. All voltages can be plus or minus 10 percent. Missing voltages can be caused by a blown fuse, a bad header pin, a bad connector, or some other electronic component. Also check the fuses and the connectors first.

Power Transformer Module (Rectifier board):
If the rectifier board connector J3 is disconnected, this will isolate the power supply from the rest of the game, giving slightly different voltage readings for TP2 and TP4.

TP1 = +5.4 vdc (AS2518-18 version), +6.5 vdc (AS2518-49 & -54 versions) feature lamps.
TP2 = +230 vdc (score displays) with connector J3 attached, 150 vdc with J3 disconnected.
TP3 = +13 to 16.5 vdc with connector J3 removed, +12 to 14 vdc with J3 connected. This voltage will become the +5 regulated voltage.
TP4 = 5.7 to 7.3 volts AC (general illumination)
TP5 = +43 vdc (solenoid voltage)
GND = Ground

The 5/12 Volt Power Train in Detail.
The Bally/Stern MPU boards need only 12 volts and 5 volts to start booting (43 volts is needed later, but for now let's keep it simple). Before doing anything, check the power train.

Go to the rectifier board and check for voltage there. The following info applies mostly to games prior to Xenon (where the power supply is in the backbox). But it can be applied to the later games, especially when testing the 12 volt and 5 volt DC circuits of the solenoid driver and MPU boards. Different wire colors may be used in newer games, but the test points (TP) and voltage readings are the same.

Check rectifier board TP3 for 12 volts. If missing, check the fuse F3. Remove the 4 amp slo-blow and buzz it out with a DMM. Check the fuse clips for damage or burns, as this is very common.

If still no 12 volts DC at TP3, check E11/E12 test points on the rectifier board. These are the two AC inputs and should read about 12 volts AC with your DMM connectors to both E11 and E12. If no voltage check the wiring to the transformer or the transformer itself. If the 12 volts AC is present at E11 and E12, then the bridge rectifier BR2 is open. If fuse F3 blows immediately at power-on, then the bridge rectifier BR2 is shorted. Part of the bridge could be not working causing only half wave rectification of the AC voltage, but the voltage will still be 12 to 13.5 volts (just the +5 volt circuit on the solenoid driver board will struggle to make a clean 5 volts, and this will cause problems like the game reseting occasionally or locking-up.)

If there is 12 volts DC at TP3 on the rectifier board but no 12 volts on the MPU board at TP2, likely it is just one wire causing the problem. Check J3 pin 8 (orange wire) of the rectifier board, as it may be burnt. It is a good idea to replace this connector pin as it handles the 12 volts distribution and is often burnt.

Next the orange wire goes to the solenoid driver board connector J3 pin 12. It makes a U-turn and heads back out J3 pin 11 and goes to the MPU board (this is why there is often a jumper between the solenoid driver board TP1 and TP3, to make sure this U-turn does not get cut). At the Solenoid Driver, the 12 volts DC heads also heads to the 5 volt regulator going through the big capacitor C23 (this smooths out the raw 12 volts DC, and usually needs to be replaced for reliability). Often there is a problem with the negative side of cap C23 that causes problems. The negative side of this cap goes back to the Power Supply in a separate wire, independent of other ground circuits. Even though all grounds end up at the same spot, this independent wire helps limit line noise. It also can lead to some weird problems like shutting down the MPU or causing massive resets.

This single white/brown return wire goes from the solenoid driver from J3 pin 10 to the rectifier board J3 pin 17. Note that these pin numbers at the rectifier board may not the same the game you are working on. The grouping of the pins at rectifier board connector J3 are often swapped around between pins 1-4 and pins 14-20. These are all ground returns and over the years perhaps the wires were moved. Keep this in mind.

The point is if this ground return wire from the solenoid driver board capacitor C23 to the rectifier board gets cut, it will shut down the 5 volt regulator and the MPU. The fastest way to do a check is to jump the left (negative) side of the cap C23 to any ground in the backbox. If the game comes up, you have found a problem with the white/brown wire.

You should now have +5 (TP1) and +12 (TP2) volts DC at the MPU board, and can start diagnosing the MPU LED board flash codes.

#31 5 years ago

A3J3 Wire Colors. Im starting to wonder if this was done incorrectly or not. in the manual I have things where there are not supposed to be things and its confusing me. Just wondering if you guys also agree?

J3 Pinout
1- empty
2- KEY
3- Brown
4- empty
5- Brown
6- Brown Green
7- empty
8- red
9- empty
10- empty
11- red green
12- empty
13- black jumper to 25
14- brown brown
15- brown green
16- black green
17- green white
18- brown green
19- black red
20- dark brown
21- brown green
22- black green
23- red orange
24-brown red
25- black jumper to 13

I really really appreciate the input and help you have been giving me. I don't typically work on older games but its been fun to be honest and definitely frustrating at times. Thank you again so much! I know the customers that will get to enjoy this pinball will be really thankful it all works

I'll get my Multimeter tonight when I go up to my location and grab it. I forgot it in my Star Trek Pro.

Thanks again,

Tony

#32 5 years ago
Quoted from policano:

when I get home I can get pics. when you turn on the game I see the orange on the displays at the bottom of the displays and then the digits and the inserts briefly come on and the drops no longer reset when power up.

Have you checked the fuses under the playfield?

#33 5 years ago

I did check the fuses. I was thinking it was a waste of time because I see power on the MPU board as it boots and the insert lights do flash briefly when powered on. I am going to test that again. It was late last night trying to do this and go to work every day

#35 5 years ago

Check the lamp associated with the Solenoid Expander Board (SEB) under the playfield. Also check the connector on the SEB for cracked solder joints and reflow with fresh solder.

#36 5 years ago

Where is the lamp on the SEB board? I don't see any lights on it. I get the displays and the inserts to flash for a half second during boot up.

#37 5 years ago

on the MPU board I'm getting 1 flash right when I turn on and then 5 flashes.

#38 5 years ago
Quoted from policano:

on the MPU board I'm getting 1 flash right when I turn on and then 5 flashes.

Here is the diagnostics to at least get 12v and 5v to the MPU - I presume this is already ok, b/c you are getting the first flash indicating 12v is getting to the board.
+++++++++ Preliminary Step: Power.
The Bally/Stern MPU boards need only 12 volts and 5 volts to start booting (43 volts is needed later, but for now let's keep it simple). Before starting the LED flash code diagnositics, check the power train. Always check the end of the powerline first, the MPU board. It must have good 5 volts DC at TP5 and an unregulated 12 volts at TP2.

If the LED is lit solid and the MPU is not booting, it can be assumed that the 12 volts is present (because 12 volts is needed to light the LED). So check for 5 volts DC at TP5, it should be in the 4.8 to 5.1 volt DC range. Many times the MPU is locked only because the 12 or the 5 volts are missing or low.

If the MPU LED is not lit, check TP2 for 12 volts DC. If 12 volts is there but LED does not (never) lights, cross the two legs (on right side) of Q2 with a small screwdriver. This should turn-on the LED. If it doesn't, assume that the MPU board's LED is bad and replace it.

If the 12 volts is missing from MPU TP2, forget about the LED and go to the rectifier board and check for voltage there. The following info applies mostly to games prior to Xenon (where the power supply is in the backbox). But it can be applied to the later games, especially when testing the 12 volt and 5 volt DC circuits of the solenoid driver and MPU boards. Different wire colors may be used in newer games, but the test points (TP) and voltage readings are the same.

Check rectifier board TP3 for 12 volts. If missing, check the fuse F3. Remove the 4 amp slo-blow and buzz it out with a DMM. Check the fuse clips for damage or burns, as this is very common.

If still no 12 volts DC at TP3, check E11/E12 test points on the rectifier board. These are the two AC inputs and should read about 12 volts AC with your DMM connectors to both E11 and E12. If no voltage check the wiring to the transformer or the transformer itself. If the 12 volts AC is present at E11 and E12, then the bridge rectifier BR2 is open. If fuse F3 blows immediately at power-on, then the bridge rectifier BR2 is shorted.

If there is 12 volts DC at TP3 on the rectifier board but no 12 volts on the MPU board, likely it is just one wire causing the problem. Check J3 pin 8 (orange wire) of the rectifier board, as it may be burnt. It is a good idea to replace this connector pin as it handles the 12 volts distribution and is often burnt.

Next the orange wire goes to the solenoid driver board connector J3 pin 12. It makes a U-turn and heads back out J3 pin 11 and goes to the MPU board (this is why there is often a jumper between the solenoid driver board TP1 and TP3, to make sure this U-turn does not get cut). At the Solenoid Driver, the 12 volts DC heads also heads to the 5 volt regulator going through the big capacitor C23 (this smooths out the raw 12 volts DC). Often there is a problem with the begative side of cap C23 that causes problems. The negative side of this cap goes back to the Power Supply in a separate wire, independent of other ground circuits. Even though all grounds end up at the same spot, this independent wire helps limit line noise. It also can lead to some weird problems like shutting down the MPU or causing massive resets.

This single white/brown return wire goes from the solenoid driver from J3 pin 10 to the rectifier board J3 pin 17. Note that these pin numbers at the rectifier board may not the same the game you are working on. The grouping of the pins at rectifier board connector J3 are often swapped around between pins 1-4 and pins 14-20. These are all ground returns and over the years perhaps the wires were moved. Keep this in mind.

The point is if this ground return wire from the solenoid driver board capacitor C23 to the rectifier board gets cut, it will shut down the 5 volt regulator and the MPU. The fastest way to do a check is to jump the left (negative) side of the cap C23 to any ground in the backbox. If the game comes up, you have found a problem with the white/brown wire.

You should now have +5 and +12 volts DC at the MPU board, and can start diagnosing the MPU LED board flash codes.

#39 5 years ago

There is an entire set of procedures if the first LED flash is solid and stays on. Lots of logic steps and tests - lets assume we can skip all that, as you only get the 12v 1st flash (power is present). then the other flashes.

Use the following for MPU LED flashes 1 through 7
Again - I won't include a whole section that goes into flash #7 failing. This should at least get you back to a full MPU boot.

++++++++++++++++++++++++
1st Brief Flicker Completed:
The Fakers Guide: If the LED briefly flickers on power-up, the CPU chip has booted and found the startup code in ROM U6, and is starting to execute startup/test program in ROM U6. So U6 (ROM), U9 (CPU), U11 (PIA), the reset components, and +5 volts DC are good (remember some Stern games also require the U2 and/or U5/U6 ROMs for the first flicker). If the LED locks on, one of these components (or some other supporting components such as the MPU's Q1, Q2, Q5, VR1, or C23, Q20 on the solenoid driver board) are bad (see above). Also the traces connecting these components together could be bad (battery corrosion!)

Techno Guide: On power-up, the U9 CPU chip requires +5 volts DC be applied before the reset line is allowed to swing from 0 to +4.8 volts. It also requires the presense of a two-phase, non-overlapping clock pulse. If these conditions are met, and if the U9 CPU chip itself is good, the LED on the MPU board briefly flickers.

The brief flicker indicates the operation is proper. The MPU has gone out to memory and obtained the starting address of the self-test from memory. The flicker indicates that it then went to that address in the U6 ROM and started to execute the self-test program in the U6 ROM.

The Valid Power Detectors circuit on the U9 CPU works with the +5 volts DC regulator Q20 on the solenoid driver board. This prevents the reset line from going high until +5 volts DC is proper at the U9 CPU chip. Q20 is supposed to go into regulation when +7.5 volts DC is applied to its input. This means that when the game is turned on, and a sufficient time (milliseconds) has passed so that C23 on the solenoid driver board has charged, Q20 switches into regulation. This supplies +5 volts DC to the MPU board.

Q1 on the MPU board (in the valid power detector circuit) does not allow the CPU chip to turn on immediately. The zener diode VR1, in series with the base of Q1 delays application of the reset voltage until C23 charges. At this point, Q1 and Q5 on the MPU board go into conduction, and the reset line at the MPU is caused to go high. Only then is the U9 CPU chip "on".

The importance of the Valid Power Detection circuit can be appreciated when the following fact is known; should the reset line be allowed to go high before the +5 volts is applied and proper, or should the +5 volt supply fail and go out of regulation, the U9 CPU chip can jump out of the program. The reason this happens is that the U9 CPU goes out to the program memory bank U1-U6 for instructions. The logic levels are wrong because the +5 volts is not proper. The MPU misinterprets the data, jumps out of the program, and executes this misinterpreted program! The U9 CPU is now like a train that has left the tracks, and it can end up anywhere. The difference is that a train will eventually stop. But the U9 CPU may continue as long as the clock circuit continues to run.

If the U9 CPU jumps out of the program, it is said to be in "run away". While it is mis-interpreting the program, it invariably overwrites the Bookkeeping function in U8 and the scratch pad RAM. An indication of a "run away" would be false data in bookkeeping. Probable cause is a faulty Q20 or C23 (or both) on the solenoid driver boared, or a leaky zener diode VR1 on the MPU board.

First Flash Completed:
The Fakers Guide: flash number one means ROM U1 to U6 are good. No first flash means one (or more) of the game program ROMs U1 to U6 are bad. Could be a mis-jumpered board, or a bad ROM chip at U1 to U6, or a bad ROM socket at U1 to U6.

Techno Guide: the U9 CPU chip next goes out to the program ROM's (read only memory) U1 to U6. It tests each chip in the bank, in accordance to how the MPU board is jumpered. When it finds the bank is correct, it flashes the LED for the first flash. A fault in the U1 to U6 ROM chips is indicated by the absense of the first flash.

The U9 CPU tests each ROM chip's function like this: in a game with ROM chips U2 and U6 (typical), the CPU first goes to U2. It fetches the first byte in U2, and adds it to the second byte in U2. It will add to this sum the third byte in U2. This continues until all bytes in the chip have been added up. If the sum of all the bytes is "0000 0000", the U9 CPU proceeds to U6 and repeats this process. If U6 has a sum of "0000 0000", the U9 CPU causes the LED to flash the first time. Fault in either U2 or U6 is indicated by the absence of the first flash.

The contents of each ROM chip have byte locations called checksums, reserved for this test routine. There is one checksum byte reserved in each 512 bytes of ROM memory. The game programmer at Bally must insert a btye with the proper value in each checksum byte location to force each 512 byte checksum to equal "0000 0000".

During the life of an electronic game, if a ROM chip U1 to U6 fails by so much as a single bit, it will be detected during this CPU test. The CPU will not continue until the defective ROM chip is replaced.

Second Flash Completed:
The Fakers Guide: a second flash means the 6810 RAM at U7 is good. No second flash means U7 (6810) or its socket are bad.

Techno Guide: The U9 CPU chip goes out to the U7 RAM and erases the contents of the first byte (U7 is a 128 byte scratch pad memory). It then tries to read back the word "0000 0000" (indicating erased). If it can read it back, it adds "1" and continues. 256 tries later, it writes the word "1111 1111". If it can read it back, it has determined that the first byte in U7 is good. It repeats this process for each of the 128 bytes of RAM in U7, one at a time. If at the end of this 256 x 128 (=32,768) tests, each time the CPU writes, it can read the same word back, the CPU cause the LED to flash a second time.

Note the pause between the first and second flashes. This is the CPU doing 32,768 tests to the RAM at U7 and repeats the process.

Third Flash Completed:
The Fakers Guide: a third flash means the U8 5101 RAM is good. No third flash means U8 (5101) or its socket is bad.

Techno Guide: The U9 CPU goes out to U8 (CMOS 5101 RAM) and makes a copy of the contents of the first half byte. It does this because U8 is battery supplied, non-volatile memory where the bookkeeping functions are stored. It then erases the contents of the first half byte, and tries to read back the word "0000 xxxx". If it can read it back, it adds "1" to the previous word (giving "0001 xxxx"). It continues to write and read until it reaches the word "1111 xxxx". When this is done successfully, the CPU restores the original contents to the first byte located in U8. It then makes a copy of the contents of the second byte, and repeats the process. It does this for the entire 256 bytes, one at a time. If at the end of the 256 x 16 (=4096) test, each time the CPU writes and reads the same word correctly, the CPU caused the LED to flash a third time.

Since the 5101 U8 RAM is in the "corrosion zone", here is a quick check of the U8's connection to other components. This will help determine if the U8 socket is bad. (Note the letter/number in parends is the address, or data, or chip enable number.)

U8 pin 1 (A3) - U7 pin 20, U6 pin 5
U8 pin 2 (A2) - U7 pin 21, U6 pin 6
U8 pin 3 (A1) - U7 pin 22, U6 pin 7, U11 pin 35
U8 pin 4 (A0) - U7 pin 23, U6 pin 8, U11 pin 36
U8 pin 5 (A5) - U7 pin 18, U6 pin 3
U8 pin 6 (A6) - U7 pin 17, U6 pin 2
U8 pin 7 (A7) - U7 pin 15, U6 pin 1, U11 pin 24
U8 pin 8 - Ground
U8 pin 9 (D10)*- U7 pin 6, U6 pin 14, U11 pin 29
U8 pin 10 (D00)*- U7 pin 6, U6 pin 14, U11 pin 29
U8 pin 11 (D11)@- U7 pin 7, U6 pin 15, U11 pin 28
(* U8 pins 9&10 shorted together)
(@ U8 pins 11&12 shorted together)

U8 pin 12 (D01)@- U7 pin 7, U6 pin 15, U11 pin 28
U8 pin 13 (D12)*- U7 pin 8, U6 pin 16, U11 pin 27
U8 pin 14 (D02)*- U7 pin 8, U6 pin 16, U11 pin 27
U8 pin 15 (D13)#- U7 pin 9, U6 pin 17, U11 pin 26
U8 pin 16 (D03)#- U7 pin 9, U6 pin 17, U11 pin 26
U8 pin 17 (CE2) - Q5 rt upper leg, U9 pin 40, U11 pin 34
U8 pin 18 (OD) - U18 pin 6
U8 pin 19 (CE1) - U17 pin 8
U8 pin 20 (R/W) - U7 pin 16, U11 pin 21, U9 pin 34, U18 pin 7
U8 pin 21 (A4) - U7 pin 19, U6 pin 4, U11 pin 22
U8 pin 22 (Vcc) - C13 left leg, R12 upper leg, CR5 lower leg
(@ U8 pins 11&12 shorted together)
(* U8 pins 13&14 shorted together)
(# U8 pins 15&16 shorted together)

If all the U8 RAM lines ring out as described above, and the 5101 U8 RAM is known "good", yet only two LED flashes are received, next replace U19 (4011). This often fixes a stubborn two-LED-flash MPU board.

Also be aware of the speed of any replacement 5101 RAM. A too-slow 5101 will may pass the initial boot-up LED code test, but can cause wack score display behavior. Turns out a bad 5101 RAM or one that is too slow will not keep up with the CPU's demand for accessing the display data. Here's a list of 5101 RAM speeds:

PCD5101P : 150nS (Philips)
5101-1 : 450nS
5101L-1 : 450nS
5101-2 : 450nS
5101L-2 : 450nS
5101 : 650nS
5101L : 650nS
5101-3 : 650nS
5101L-3 : 650nS
5101-8 : 800nS

The Phillips brand of 5101 is the best, as it's the fastest and will work in all Bally/Stern MPU board applications. Sterns MPU-200 need 450ns or faster RAM, Bally MPU -35/-17 need 650ns or faster. So you can see that some 5101 RAM just won't work properely in Bally or Stern MPU boards.

Fourth Flash Completed:
The Fakers Guide: a fourth flash means the U10 PIA (6821) is good. No fourth flash means U10 (6821 PIA) or its socket are bad. Or battery corrosion had broken a trace going to U10. Or the chip leading to U10 is bad, which is U20 (4502).

Techno Guide: The U9 CPU chip now tests the first 6821 PIA chip. There are two of these chips on the MPU board, which are identical and interchangable. The test for both is the same.

To determine if a PIA chip is good, the U9 CPU does the following:

The CPU accesses, by means of input RS0, RS1, CS0, CS1 and CS2 each of the two full byte registers used to store the port initialization information. If does this, one register at a time. After it completes the first register, it repeats for the second. It goes through 256 tests similar to that used to check each byte in U7 (second flash). If each time the CPU writes a word into the register, it can read the same word back, it continues to test until completion.
The CPU accesses, by means of input RS0, RS1, CS0, CS1 and CS2, each of two full byte registers used as data output registers when PA0 to PA7 and PB0 to PB7 are used as outputs. It does the same type of test on each register as described just above. Again if no faults are found, the test is continued until completion.
The CPU then accesses, by means of input RS0, RS1, CS0, CS1 and CS2, the two ports CA2 and CB2. The port is initialized as an output. The port is then written into to see if it can store a "1" and then a "0".

A total of 4 x 256 + 4 (=1028) test steps are required to test the PIA chip. However, there are internal buffer amplifiers used with the PB0 to PB7 output registers and CB2 port register which can not be tested by the CPU. Access is only to the register; if the buffer is open, it does not interfere with the registers ability to be written into and read from by the CPU. It is this uncertainity that reduces the accuracy of these test to 99.5%.

Also check and make sure that the MPU connector J1 and the lamp driver connector J1 are not mixed up! These two connectors are about 4 inches apart, and are keyed the same. If only three MPU LED flashes are seen, this problem can also sometimes show the score displays with an '8' or a '9' in the hundreds place.

Also I recently fixed a game (Bobby Orr Power Play) where sometimes it would not get the fourth MPU flash, but sometimes it would get all seven. If it did boot, the score displays would flicker and only show some of the six digits. The problem was a trace going to U10 on the component side of the MPU right near the battery that was intermittent from corrosion. After I cleaned up the corrosion (sanded and neutralized) and repaired the broken trace (it was obviously open after sanding), the MPU booted and the game worked correctly.

Fifth Flash Completed:
The Fakers Guide: a fifth flash means the U11 PIA (6821) is good. No fifth flash means U11 (6821 PIA) or its socket are bad. Note the flipper enable relay will usually click on/off at about the fifth flash. The lack of a fifth flash could also be a bad resistor connecting to U11 like R134. Another issue could be a bad score display, which can cause the MPU board to stop during the 5th LED diagnostics. Disconnecting all the score displays (power off), then reconnecting them one at a time (power off) and rebooting can help identify a bad display that is dragging down the fifth MPU LED flash.

Techno Guide: Same test is performed on U11 as was performed on U10. See above.

Sixth Flash Completed*:
The Fakers Guide: a sixth flash means the PIA at U11 (6821) and the U12 timer (5550 chip is good. No sixth flash means either PIA U11 (6821) or its socket is bad, or the U12 (555) timer is bad. Lack of the 6th flash (five flashes only) can also mean a problems with the zero-crossing detector. Often this is the MPU board's R113 resistor (2k ohm, near the J4 connector) is open. This resistor takes the 43 volt DC coil power to the zero-crossing detector circuitry and normally runs hot. Hence it may eventually go open, so check it if only 5 flashes from the LED are seen. Thanks to Ray J. for this tip.

Techno Guide: The U9 CPU chip monitors PIA2, port CA1 (U11). If transitions from high to low are detected, the CPU decides the Display Interrupt Generator is working. If U12, a 555 timer, or any associated circuit component fails, the CPU will not flash the LED the sixth time.

* Note on Baby Pacman and Granny and the Gators, this flash step is skipped and not tested.

Seventh (Last) Flash Completed**:
The Fakers Guide: Getting the seventh flash means the CPU board has passed all self-tests. After the 7th flash, the LED should have a very dim glow to it (this "dimness" occurs because the game is strobing the switches), and the game should be in 'attract' mode. No last LED flash generally means there's no +43 volts DC for the solenoids (power transformer fuse F4 is probably blown), PIA U10 (6821) or its socket are bad, or U14 is bad.

Remember the 7th flash is looking for 43 volts (or 6 volts AC in the case of Baby Pac's last flash) on the MPU board. Note this test for voltage is performed on Baby Pac too (the prior flash step is skipped, giving Baby Pac a total of 6 LED flashes). This is done thru PIA U10's CB1 port. The PIA is looking for the zero-cross of the 43 volts (or 6 volts for Baby Pac). If 43 volts is not present (rectifier board F4 fuse blown), the last flash will not occur.

If the game locks_up after the 7th flash, try unplugging the sound card and reboot. If it then works check the isolation power diode CR3 on the sound card - sometimes this bad diode on the sound board can lower the 43 volts enough to stop the MPU board's 7th flash (Star Trek comes to mind). Also Check the solenoid driver board cap C23 is in good condition. There is also a chance the 555 timer chip and/or C17 could be bad on the MPU board.

The 43 (or 6) volts can be "faked" and not supplied (for example if you are booting the MPU board on the work bench), and the last LED flash can happen. Just connect the top leg of resistor R23 (leg closest to chip U12) to the top leg of resistor R17 (leg closest to TP3) using an alligator test lead.

Techno Guide: The U9 CPU chip monitors PIA1 port CB1 (U10). If transistion from high to low are detected, the CPU decides that the zero crossing detector is working. If U14 fails and the CB1 line is stuck high or low, the test will also fail. The zero crossing detector circuit input is the +43 volts DC line that is used for the solenoids. If the fuse in that line (F4 on the power transformer module) is blown when the game is turned on, the CPU will not flash the LED the seventh time.

** Note on Baby Pacman and Granny and the Gators there is no 7th LED flash.** These games only had six flashes instead of seven. The easiest way to determine if the MPU board is a -133 designed for Baby Pac/Gators and 6 flashes is to look at the J4 connector (lower left corner) around pin 19. Between L1 and L2 (the very large inductors that look like 2 watt resistors) is either a diode (cr52) or a resistor (r113). If it's a diode, this is a -133 MPU board and there will only be 6 flashes. If it's a resistor, it is a -35 or -17 MPU board and there should be 7 flashes. Converting the -133 MPU to a -35 MPU is very easy do. Just replace the 1N4148 diode at CR52 with a 2k ohm 1/4 watt resistor. New EPROMs will need to be burned too of course For more information on the -133 MPU board see here.

Game Initialization.
The U9 CPU chip now initializes the two PIA's U10 and U11, assigning to each port its role as either an input or an output, as required. It then clears out U7 (6810 RAM). Now the CPU takes a picture of the settings of fixed switches S1 to S32 on the MPU board. It stores this "picture" in memory in chip U7. The CPU next jumps to a routine which turns on the "Game Over" feature light, lights the "Ball in Play" light, and the "Credit Indicator" light if there are credits stored in memory. It resets the drop targets and activates the saucer kickers or any kicker associated with a playfield device that can trap the ball and keep it out of the outhole. It then energizes the coin lockout solenoid to allow the game to accept coins (unless the credit maximum was met). Playfield and backbox feature lights associated with and appropriate to animation effects are turned on. With the game tested and initialized, the CPU now divides its time between monitoring momentary switches for closure (coin switch, credit button) and updating displays (lamps and score registers).

Problems/Solutions with the Seventh Flash.
Of course first verify that the MPU board is *not* a -133 model with Baby Pacman or Granny and the Gator EPROMs (hint: if U2 and U6 are a 2732 and 2532, suspect a -133 MPU board). A few paragraphs above describes how to tell if it is a -133 MPU board.

If fuse F4 is blown on the solenoid board, the seventh flash will not occur. But what if there is a problem on the playfield which is forcing this fuse to blow (stopping the final LED flash on the MPU board, hence stopping your MPU diagnostics)?

The easiest way to deal with this is to remove the solenoid connectors from the solenoid driver board to the playfield. These connectors are on the left side of the solenoid driver board, and the one connector at the bottom right of the board too. This should allow the F4 fuse to be replaced, and the completion of the MPU booting process.

To help find the playfield coil that is causing the F4 fuse to blow, replace the connectors one at a time on the solenoid driver board (with the game off), and reboot the game. This will help issolate the bad coil.

Another thing to try: remove the under-the-playfield coil fuse, and replace fuse F4. If F4 does not blow, then one of the coils under the playfield is somehow shorted or staying energized (and blowing the solenoid driver F4 fuse). If fuse F4 still blows, there is either a problem with the backbox knocker, or the cabinet coin door lockout coil, the solenoid bridge rectifier (on the rectifier board), or the rectifier board's varister.

Also try removing connectors J1 and J3 from the rectifier board (this moves the solenoid power back a step further, not allowing it to get any further than the rectifier board). Replace fuse F4 on the solenoid driver board, and turn the game on. If the fuse still blows, the solenoid bridge rectifier (on the rectifier board) or the rectifier board's varister is probably at fault.

If it is a coil under the playfield, check the coils to see which one energizes when the game is powered on. Or disconnect a wire on each solenoid, and re-attach each wire, one at a time, until the fuse blows. At this point it could be the coil, coil diode, or coil driver transistor at fault.

#40 5 years ago

If you are getting the first flash, you have power to the MPU at 12v.
If you get flashes 2-6, you should be ok with U-chips on the MPU for Rom, Ram and logic.
If you fail to get flash 7 - the likely culprits are 43v missing, which can be isolated as described above by removing the solenoid driver board left side connectors and the lower right connector of the board, to take the solenoids out of circuit.

You should be able to replace the F4 (under the PF for coil control) without it blowing and be able to completely boot the MPU. You can also remove J1 and J3 from the power board to isolate solenoids one step back in the circuit chain. If you have the PF solenoids off, and the F4 still blows, its a shorted coil off the PF (knocker, coin lock-out) or the BR on the rectifier power board.

The odd thing is that your MPU was fine - and then it stopped, so a coil short or SDB connector to the MPU getting disconnected or a wire pulled a little bit, would make sense, as it could have caused a short or bad 43v to confuse the MPU flash #7.

#41 5 years ago

I will post the squak and talk diagnostics, when the MPU is back to normal.

#42 5 years ago

I've seen 5 flashes notoriously on bally mpus that have battery corrosion damage.

#43 5 years ago

Ok heres what I got today. I replaced the MPU and Driver Board. Game plays great again with the exception of no sound. No LED on sound board. Once I get the game fully working I am going to start working on the other boards. Everything is working great but no LED on sound board. I have replaced all the CAPS on the S&T board.

#44 5 years ago

On the replacement Alltek Driver board I installed today I noticed the +43VDC is not lit. I checked all the fuses and they are all good. Everything is working fine except no lit on the driver board and no sound LED.

#45 5 years ago

If I pull the F4 fuse the game doesn't boot at all. Im just confused now It appears I must be getting voltage but I'm not get 8 flashes on the Alltek board MPU or the LED on the driver for +43. Still not sure how its related to the sound board that doesn't work or have any LED light on at all.

#46 5 years ago

Ok, after a nightmare of connectors I found out the problem. the +42 is weird. I do have it the light is just not on. the TP shows the correct voltage. As for the S&T board. its the connector. I redid a few of them and its working now. Just need to find out what those molex connectors are called. The wires pass through there not terminate there.

#47 5 years ago

Connectors, connectors, connectors - I got the Molex kit from pinballlife, and have used it a dozen times, and all but one time, it was either the connector or the header pins (kit comes with matching sets of each). The only other time it wasn't a connector, was a melted trace from someone jumping a fuse - lucky the short didn't cause a fire. First think I did was replace the regulator board.

If you have charred connectors at J1, J2 and J3 of the rectifier board, I'd replace those header and molex connectors too.

1 week later
#48 5 years ago

Well I'm back at it again tonight. Literally the eve of my kiss launch party and sound is completely dead again.

Brand new mpu
Brand new Driver
Brand new lamp board
Brand new connectors.
Capped the S&T board.
Led light will not light. Everything else 100%. I cannot believe how frustrating this old game has been for me

Does anyone have any suggestions? Doesn't seem like they remake this S&T board.

#49 5 years ago

What brand are the PIAs on the S&T? If they're AMI try swapping them out.

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