Chattanooga, TN
Only blows f4 fuse when I connect J3 on the rectifier and J3 on SBD.
(Topic ID: 180997)
SDB J3-5 feeds the flipper enable relay. Rectifier board J3-9 feeds the solenoid bus. Two good places to start.
Yes. It enters the SDB at J3-5. Start there and look for a ground. Check for continuity between 5 and the connections on either side. If those are good, move on up the circuit and look at CR20 and the flipper enable relay. If someone redid the connectors on the board or incorrectly did one of ground mods to the back of the SDB that could be your problem.
Another thought is to reconnect the yellow wire at the rectifier board and disconnect it at the SDB and see if it still blows. If so, the problem is in the wire. If not, its on the SDB.
I went ahead and replace cr20 and q15. Still blows the fuse. I disconnected the yellow wire the SBD and left it connects at the rectifier board - fuse f4 blew.
I did the ground mods on the back of the board. Tp1to tp3 and c26 negative to ground and C23 negative to ground.
Quoted from StratDoc:I went ahead and replace cr20 and q15. Still blows the fuse. I disconnected the yellow wire the SBD and left it connects at the rectifier board - fuse f4 blew.
That makes it sound as if the SDB is not the problem. If you disconnect J3 from the SDB and leave J3 plugged in to the rectifier the problem lies elsewhere.
Try pulling 9, 12 and 13 out of J3 and see if it still blows. If not, plug them back in one at a time and see what makes it blow. I hope you haven't pulled all of your hair out yet...
I think I found it. Both A3J35 and A2J9 connect to the sound board module at J1-9 on the sound board. If I disconnect sound board - only thing I had not disconnected and do not know why I did not see it.. I think the transistor Q1 is bad. It is TIP29c. Trying to figure out if I have an equivalent
It was th cindy or pin on the sound board. Repinned and now f4 does not blow.
I am showing no voltage at TP1 on the SDB. It should be reading 5vdc and I am showing .6vdc. I have installed the repair kit from BigDaddy so transistors, etc have been replaced. The voltages coming off the rectifier board are all within spec.
That 12vdc goes through Q-20 and a few other components to make your 5VDC at TP-1. Trace the power along the path and see where it stops. And be careful, there is deadly amperage present on that board.
Quoted from StratDoc:Yes, tp5 registers correctly.
and this comment --
I have voltage a c23 and c24. Nothing on the other side of q20. It is a brand new transistor and continuity checks out okay and it does not test that is is shorted to the heat sink.
These both suggest 12V coming into board but not getting to Q20. No voltage on either side of Q20 --> broken trace or no connection to Vin pin of Q20.
I believe this is where Mk1Mod0 was going with posts #64 - 66.
Q20 was part of a rebuild kit from BigDaddy Enterprises. I will check traces and pull the transistor. I will reinstall without the heat sink to see if I get volts. Maybe it is touching the heat sink and my multimeter is not picking it up. I will post back later what I learn.
Q21, Q22 and Q23 are part of the high voltage circuit. Ignore those until you get the +5V running.
Q20 -- only thing that will work there is a variation of a 323 type TO-3 package regulator. Q20 is actually an integrated circuit, not a transistor.
I replaced q20 and now have fairly close to correct voltages on the SDB. I have 15vac at tp5, and 4.95vac at tp1 and tp3. Tp2 is 153vac and tp4 is 254vac. The MPU is also showing close to correct voltages tp1 4.87vac and tp2 14.8vac. I have remove the battery - at some point there was corrosion and someone cleaned it up and replaced a lot of the board and added a new rechargeable battery - but the led does not light at all. I replaced the led and it still does not light. If I am getting correct volts at tp2 it should light??
Do you get the quick flash or nothing at all? A good start would be to carefully remove the eprom and rom chips and set them back in maintaining correct orientation. There is probably some corrosion on the legs and reseating them will help. You're getting close!
Shawn
Should have 5VDC at TP1, 11 at TP2, 21 at TP3, TP4 is your ground and 5 at TP5. If these are not close, we'll have to back up until they are.
Look at the schematic for the MPU and see where the TP3 gets its power and start tracing from there.
Will do. Off to work so will pick it up later this evening. It traces back to the transformer a2j3 12 solid gray wire.
At some point I think Twobit scores out of Austin rebuilt the board. It has a couple of plastic authentication locks/rings attached to the MPU board and $250 recepits attached by string to the MPU.
Quoted from StratDoc:I replaced the led and it still does not light.
No flash at all that I can tell. I turned the lights off and could not see anything.
Did you install the LED the right way around? (LEDs are directional). When you power the MPU board the default state for the LED is ON. The board needs to be somewhat functioning to initially switch the LED off and that's what you normally see as the first flicker.
If you see no light/flicker from the LED at power-up, you need to fix it first otherwise you're working blind.
The 21VDC at TP3 isn't required until the last part of the power on self test (7th LED flash). It's actually sourced from the solenoid 43VDC at the rectifier board, so check fuse F4.
To clarify, these voltages you're measuring at the MPU board are DC. You keep mentioning AC 
Quoted from Quench:To clarify, these voltages you're measuring at the MPU board are DC. You keep mentioning AC
Unless they are getting AC, in which case there's a problem... 
Further troubleshooting the LED not even turning on:
1. One side of R29 should have 11+VDC. That powers the LED
2. the other side or R29 should have continuity to the LED
3. You should be able to test the LED with your diode test: black lead on the side attached to R29, red lead on the other side should show no continuity, swapped leads should get some voltage drop (and the LED might even light dimly)
4. R25 carries the signal from the PIA to the Q2 transistor to control the LED. With U11 removed, you should get 5VDC on one side of R107 (and a bit less on the other side). This 5V should then flow through R25 to Q2.
5. If there's near 5V where R25 connects to Q2, and there's 11VDC where R29 connects to the LED, then the LED should be on, unless you've got a problem with Q2.
6. I'd test every component in the circuit against the schematics, and the continuity between them to be certain
. yes, there really would be a problem if it was AC and not DC. I will check the suggestions later this evening. I hate it when work interferes with more important matters.
Quoted from StratDoc:I get 4.89 DVC on one leg of R25 with u11 removed.
Slight typo above, R25 should read R28. With U11 out, measure the voltage on both sides of R28.
Also measure the voltage on the three legs of the Q2 transistor (left pin, lower right pin and upper right pin).
The lower circumference around the LED has a flat part to it closer to one of its pins. This flat part should be facing the right side of the board.
Quoted from StratDoc:R29 has 14 dvc on both legs
3.4dvc at r28 with u11 removed. Less than 1 volt at q2 on all legs.
This indicates a problem with the LED - either it's faulty, soldered in backwards, or has an open circuit on the PCB to one of its legs.
Okay. I will check later this evening when I get home. It is a new LED from BigDaddy Enterprises. It could be soldered in backwards, but when looking at it this morning I could not discern a distinct flat part next to one of the legs. It is flat on both sides. The old LED I still have but it wasn't working either, which is why I changed it out.
Quoted from Quench:Slight typo above, R25 should read R28
Oops! Darn PDF scans...
Quoted from Quench:This indicates a problem with the LED
Curious- why with the led?
<1V seems low to turn on Q2 to me
Quoted from StratDoc:Less than 1 volt at q2 on all legs.
At least one of these legs should be connected directly to ground. When you say <1V, do you mean 0.8V, or something like that? One of the legs should read <0.05V
Quoted from zacaj:Curious- why with the led?
<1V seems low to turn on Q2 to me
All three pins of the transistor were reported as less than 1V. So if the collector pin on the transistor is sitting at <1V the transistor is either fully turned on or lost pull up voltage connection through the LED.
R29 has 14V on both legs. If Q2 transistor is turned on and there's no open circuits, then the LED has 13-14 volts across it meaning the LED is either faulty or installed backwards. The LED should only have about 2 volts across it when switched on with most of the remaining 11-12V sitting across R29.
If there's an open circuit to the LED then hopefully it's visible.
Quoted from StratDoc:It could be soldered in backwards, but when looking at it this morning I could not discern a distinct flat part next to one of the legs.
The picture below shows the LED better than I can explain. The flat side should be facing the Q2 transistor. Check for damaged traces on the circuit board to the LED aswell.
it is one quick flash followed by one longer flash.
I did, no luck. Also tried to resolder the legs of the mount to the board connector and found a missing leg. Should I just order a new one or a whole kit of chips and mounting connectors. or, am I better off biting the bullet and buying an altek board and selling this one?
Quoted from StratDoc:Also tried to resolder the legs of the mount to the board connector and found a missing leg.
Not quite sure what you mean. Can you show a picture?
Just confirming, it was the U7 RAM chip you tried reseating?
Post some clear pictures of the MPU board (back and front) around the U7 chip.
Quench,
Attached are front and back photos of U7. The trace lines where already there from when someone else tried to repair the board. I was not very clear in my last post. I was trying to resoldered the 24-pin socket after reseating the chip had no effect - thinking maybe cold solder joint - when I noticed that one of the socket legs was missing. I went ahead and pulled the socket. Some of the bad solder work on the back is mine and some of it was already there. The RAM chip at U7 looks newer than original.
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