One last try here.
I replace the u25 with a socket and then installed a NVRAM6116. All the solders look good to me. I checked continuity. I do not think I damaged any traces or pads.
But as soon as I turn the game on, I get a "1" on the MPU LED. Which is a U25 error. I pulled the board out again, and everything I did look ok to me.
I am at a loose as what to do next. Right now the board is sitting on my work bench.
Ideas ??? please
Quoted from JethroP:Can you provide clear close up pics of the socket/repair?
20201227_141951 (resized).jpg20201227_142023 (resized).jpgYou should clean that up with some flux remover and an acid or tooth brush so we can see it better but there looks like some damage was done to pads and possibly some of the adjacent traces. Also what type of NVRAM did you install and do you possibly have another to try to ensure the chip is good? Of course be sure it's installed in the proper polarity.
Quoted from bobukcat:You should clean that up with some flux remover and an acid or tooth brush so we can see it better but there looks like some damage was done to pads and possibly some of the adjacent traces. Also what type of NVRAM did you install and do you possibly have another to try to ensure the chip is good? Of course be sure it's installed in the proper polarity.
Used Pinitech Nvram6116, Chip is new Yes it is installed with proper polarity. I cleaned it up some. maybe you can see better.
20201227_151743 (resized).jpg20201227_151747 (resized).jpgIt looks like some of the solder joints are cold. Also, you said you checked for continuity from the socket to the trace on the backside? How about checking pin to pin, or pin to adjacent traces? How about the topside of the board....What does that look like? Are there traces on the other side as well? Picture the other side perhaps?
Quoted from JethroP:It looks like some of the solder joints are cold. Also, you said you checked for continuity from the socket to the trace on the backside? How about checking pin to pin, or pin to adjacent traces? How about the topside of the board....What does that look like? Are there traces on the other side as well? Picture the other side perhaps?
Yes I checked continuity from the socked to the trace on back It was good
I check continuity pin to pin and pin to adjacent pin, no continuity
20201227_161254 (resized).jpg20201227_161314 (resized).jpg20201227_161329 (resized).jpgQuoted from Eagle509:Yes I checked continuity from the socked to the trace on back It was good
You need to see if you have continuity from the traces on the back to the traces on the front. The best way to do this is by testing from the new socket pins to other chips that connect to this ram chip.
For example check U-25 DO pin to U-26 DO pin. Then U-25 AO pin to U-26 AO pin. And so on.
Capt (resized).PNGQuoted from GRUMPY:You need to see if you have continuity from the traces on the back to the traces on the front. The best way to do this is by testing from the new socket pins to other chips that connect to this ram chip.
For example check U-25 DO pin to U-26 DO pin. Then U-25 AO pin to U-26 AO pin. And so on.[quoted image]
Seems to be some issues with what I just tested. Thou not sure I really understand the schematic
so let me tell you what i found in layman's terms
Below is a pic of the u25 socket, on the left side i did not have continuity on Pins 5, 8 and 11. On the right side pin 4.
so now what do i do??? I really appreciate the help
20201227_175510 (resized).jpgQuoted from Eagle509:Below is a pic of the u25 socket
Just so you know, you installed the socket backwards. The notch on the socket should have been facing the "B" cap.
Which way did you have the chip installed?
I had the chip oriented the same direction as the other chips on the board.. I just didnt even notice the notch on the socket
Pretty sure at least some of the issue you have is continuity thru the board from top traces to bottom side. Follow GRUMPY advice:
You need to see if you have continuity from the traces on the back to the traces on the front. The best way to do this is by testing from the new socket pins to other chips that connect to this ram chip.
For example check U-25 DO pin to U-26 DO pin. Then U-25 AO pin to U-26 AO pin. And so on
ok i did all the above. Progress. It came up. I set it to free play and it took it. Comes up in attract mode, but does nothing further. I ran all the diagnostic test, all prefect except for the coil test. Nothing happens at all.
So close, but so far.
Now what ???
Just color me stupid. I have no idea how to "Check the blanking signal"
I think I maybe over my head. But it seems so close to working
The blanking signal is a safety for the displays and the coils. It keeps them turned off until the CPU booting process is finished. Once the CPU is booted the blanking signal is active and will stay active as long as the program continues to run. You can test this a few ways. If you read the manual on the seven segment display that is on the CPU board, it will tell how to let the CPU test the blanking and show the results on the seven segment display. Another way is to measure the voltage on the test point on the CPU labeled Blanking. Let me know what you find.
Coin door open, pushed switch SW2, board displays an "8" then changes to a "0" and a beep. Ran the coil test again, nothing activates. But during the coil test, the flippers do work, if that means anything.
Since the flippers work, and you get a 8 on the display, sounds like you have booted. Are the score displays working? Have you checked F-2 and F-4 fuses on the power supply.
displays work, F2 and F4 on the power supply both blown. Replaced, game started, but no flippers. checked fuses and F4 had blown again. and that was my last 2.5 amp fuse
When I first turned it back on after a few years of sitting , the displayed said "adjustment Failure". I opened the coin door, went thru the menus and set it to free play. The game played except the top Jet Bumper did not work, and the left sling shot was super week.
I replace the batteries, went thru the process again, setting to free play. But the setting would not save.
So then my repair attempts commenced
1. Replace the coils on the Jet Bumper and Left slingshot
2. Replaced resistors Q75 & Q77
3. Replace transistors Q74 & Q76
4. Replaced 7402 chips at U45 & U50
5. Unsoldered U25, replaced with socket
6. Installed NVRAM 6116 From Pinitech
7. Replaced all the fuses with correctly sized fuses.
And you know the rest.
Do you have a DMM?
If yes, do you know how to use it?
If no, you will need to purchase one or send board out for repair.
Ok, lets start with why the fuse is blowing. Most likely a coil is locking on. Here is how you find out which one.
Start by disconnecting the control wire for every coil in the game. If you look at the solenoid page in the manual it states that connectors 1J11, 1J12 and 1J19 control all the coils. Once you remove these 3 connectors the coil/coils can not lock on any more unless there is a pinched wire that is grounded. Take the black lead from your DMM and stick it under the ground braid so it makes a good connection. Set DMM to ohms, and use the red lead for testing. There are 22 solenoids in the game so there are 22 TIP122 transistors that need to be tested. There is a group of 8 above 1J11 another group of 8 above 1J12 and a 3rd group of 6 to the right of the yellow relay. Touch the red lead to the metal tab of each one of the 22 TIP transistors. They should all read .600 megaohms or higher. 6000 ohms and lower is a problem. Note any that read abnormal. Now turn on the power, start a game and retest the TIPs the same way and note any abnormal readings.
I disconnect the 3 connectors, set the DMM to OHMs, only transistor I'm getting any reading on is Q75, its 2.5.
So am I missing something here or do I have a disaster?
I can pull the board again tomorrow and check each transistor. Or is just time to call it quits for now?
Quoted from Eagle509:I disconnect the 3 connectors, set the DMM to OHMs, only transistor I'm getting any reading on is Q75, its 2.5.
So am I missing something here or do I have a disaster?
I can pull the board again tomorrow and check each transistor. Or is just time to call it quits for now?
You may have to scratch the metal tab with the probe to make good contact. If you are getting an OL reading on the meter that is fine as long as you are making good contact with the metal tab.
As far as Q-75 goes, was this with the power on or off? 2.5 ohms is bad, but if it was with the power on it maybe another component causing the issue.
Quoted from dmacy:Just wanted to add that grumpy is extremely helpful and will help you narrow down your issue.
And the patience of Job!
Quoted from Eagle509:it was with the power off. I haven't tested with the power on. Will do that in the morning.
Since the power was off, then Q-75 transistor is bad. Since you changed this before, there must be something else bad causing the transistor to go bad. Like a bad or backwards diode, a shorted coil, a bad predriver transistor, a bad nor chip or a misadjusted kicker switch.
Also post a pic of the kicker coil.
Tested the transistors with the power on, game started, 3 plugs not attached.
Q75 5.7
Q6 15.02
All others 0.0
Below is a pic of the kicker coil. The coil is newly installed. I believe I replaced Q75, before I replaced the kicker coil. So the old kicker coil may have caused Q75 to blow. I do have some spare transistors
20201230_092944 (resized).jpg20201230_093000 (resized).jpgif it isn't one thing, its something else. I replace to coils, bought from Action Pinball. When I installed them, I soldered the wires back on, if the same orientation as the old coil.
But it seem Pindel, you are correct, the diode on the new coils is reversed on the new ones. Go figure, they came like this
So I assume that i need to just switch the wires on the 2 coils that I installed.
Yep. No biggie. That’s how you learn. I knew absolutely nothing when I started. I screwed up a lot of stuff but got an education that is valuable.
Quoted from Eagle509:if it isn't one thing, its something else. I replace to coils, bought from Action Pinball. When I installed them, I soldered the wires back on, if the same orientation as the old coil.
But it seem Pindel, you are correct, the diode on the new coils is reversed on the new ones. Go figure, they came like this
So I assume that i need to just switch the wires on the 2 coils that I installed.
On the kicker coil, leave the wires as they are. Cut off the diode and install a new one, but this time you will have the silver band facing the red/ white wire.
This is why F-4 was blowing.
You will also have to replace Q-75 too.
other coil is the same way. I will have to try and locate some diodes locally, or will have to order online. If online I will be at a stopping point for a while.
Q9 should have been 576
I found a couple diodes I can use for the 2 coils. Will do that tomorrow, plus replace Q75 and Q76.
Then we will see what happens next. Should I leave connectors 1J11, 1J12 and 1J19 disconnected when I power it back up, to insure F4 doesn't blow again
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Kent, WA