Picked up a Gorgar project, nice condition, but not booting currently. I have been following along with Piniwiki and other sources, so here's where I am currently:

MPU appears to be a System 4 instead of System 6 board. As determined in my other post, this should be okay, assuming it was done correctly.

2.5A and 8A fuses were blown and "jumpered" with pieces of household wiring (ugh). Removed that mess, replaced fuses. Then I unplugged everything aside from J1/J2 on the Power Supply board, turned the game on. GI all came on, and speaker is humming a bit. I tested all the voltages, and they're within spec, so that's good.

Checked over the MPU, and found the 6800 Chip was installed backwards (ouch). It was also really loose and one leg bent. I fixed all that.

Reseated all the other connectors, replaced the batteries (no corrosion anywhere that I saw). I verified that 4.6V was appearing on the 5101 chip where it should, and checked that the battery holder is doing its job.

Knowing that 6800 was probably dead because it was in backwards, I figured I wouldn't get much, but tried firing it up. LEDs on the board come on for a moment, then go out and don't come back on. Every once in a while, Gorgar says something like "You Beat Me" when it turns on, but not often. The Credit and P1 displays come on, but are missing various segments. Based on what I'm seeing, it's in Audit mode (the 04 00 on credit is pretty clear, and it's 14### something up on the P1 display).

I ordered a new 40-pin Interconnect Kit (done these on several System 7's and a System 6 before). Also ordered a new 6800 Chip (hoping I don't need 6802 instead? Can someone verify?) I have some spare 5101 chips from other games where I installed NVRAM, so I assume if that is bad I can socket that and replace it with one of my spares for testing.

Any other suggestions while I wait for parts? Thanks!

Yes, I can scroll through the audit stuff with the buttons on the coin door (though with several segments out it's hard to read). Someone cut all the wires to the switch that detects the coin door as open or closed. Should I fix that? Wasn't sure if that was done on purpose, or if that's a bad thing on this game.

I also tried the quick on/off trick, no luck, just keeps going to audit. Wondering if that 5101 is bad... it's getting the proper voltage from the batteries on pin 22. It's a little higher than I expected (4.7VDC), but it's there. I'm going from the repair info section where it says:

"If the batteries are dead, or the battery holder is damaged, or the blocking diode D17 has failed, or there's a bad IC19 RAM 5101 chip, or battery corrosion has damaged the CPU board, the game will power up into "audit mode". "

And following those instructions as best I can.

Oh, tested D17 as suggested. Seems good. On the banded side it's 4.69VDC and on the other it's 4.90VDC. It's supposed to drop off a bit like that from what I read... hopefully it being high isn't a big deal. They're brand new batteries, so I assume that's why it's not in the 4.3 range mentioned in the guide.

Looks like they're cut and twisted together. I see Black/Red and (2) White wires tied together and taped up. Looking at the schematic, I see those wires labeled for "Memory Protect Interlock Switch", right along with the related items like the Advance, Manual-Down, Auto-Up switches.

Separated the wires and tried again, still no luck sadly.

Sadly I do not have a programmer, but know some people that do if I decide to check your stuff out. Thanks

Okay, some updates...

Fixes:
I replaced the 40-pin interconnect, socketed the 5101 RAM position, and added a known good 5101 chip. I also reflowed all of the headers on both boards and replaced a bad transistor I found on the driver board.

Results:
Powered up to the same result, audit mode. Several segments out on P1 and Credit displays, but I know it's audit mode from what segments remain since I can still basically read them.

Then I decided to pull the batteries and try the quick on/off trick... and sure enough the game went into Game Over mode! Weird. The voltages seemed a little high from the batteries to the 5101 (4.69 at pin 22), maybe something was strange with them. But with them out, I can get to Game Over it seems.

The credit switches were all cut from their wires, but I was able to jumper over and add credits. I pressed start and the back left Drop Target Reset immediately fired to reset those targets. Middle drop targets I'm not sure, need to check. Ball did NOT kick out, but flippers work. Pops also work. Scoring seems to work as well. No Sound at all though sadly. I added multiple players to see if the outhole would register and advance to the next player, and it does, so the switch there seems to be good. I'll have to look at the transistor for the outhole kicker and check that solenoid I guess.

Displays are definitely weird. Player 4 is perfect. Player 3 is dead. Player 2 is semi-functional, but unreadable, and Player 1 is missing the bottom row and top right segments. I swapped the Player 4 and Player 1 displays and the same issue appeared, so I assumed it was the main display board or the connector. Cleaned and tested the connector, no change. Then I swapped Player 1 into the Player 4 position (since I knew that came up good) and it showed the exact same segments out, so I'm thinking the display itself is bad (I noticed small electrical spark/flickers in the display glass near the bottom). But if it's the display, I don't know why the 4P display didn't work in the 1P position? Strange.

To Summarize:

- 40-pin and 5101 (now socketed) replaced, all headers reflowed, transistor replaced on driver
- Removing Batteries allows on/off method to get me to Game Over
- Can manually credit up and start game, ball doesn't kick out, Flippers/Pops/Scoring seem to work.
- No Sound
- Displays P1, P2, P3 and Credit are having issues. P4 is okay.
- Still waiting on my new 6800 chip. Tried 6802, no luck.
.

Edit: Suggestions welcome. Wondering if there's anything else I should do while I wait for that 6800 chip? I am surprised it boots at all knowing that chip was probably messed up by someone putting it in backwards for a while!

I forgot about that! Thank you, and YES it does work! All the sounds, and all the speech just came out.

Also, just tested resistance on the outhole coil... it's 0.9ohm, so pretty sure it's in need of replacing. The transistor I replaced? You guessed it, it was for that coil and was toast. Guessing it went, and then the coil locked on, because it's cooked too.

The coil in there is one I don't recognize... guessing someone tried to replace it and didn't do so well. Originally a SA-23-850-DC was used per the manual. Looks like I need a AE-23-800 as the newer replacement. Someone put a "Quality Coils" 04-1293 in there... which I've never seen before I don't think.

As for other coils, I just tested everything I think, and they seem good. Knocker is disconnected, as is the coin lockout, but the rest seem ok. Pops, Flippers, magnet in the pit, eject hole on the left mid area, all good. The drop target coils are good, but the middle one is getting jammed halfway up (bad sleeve I think, checking that soon). So it's pretty much just the outhole right now.

So I swapped in the SA-23-850-DC coil from my Space Shuttle outhole, and it still didn't fire, which was odd. I checked the associated transistor again (Q15) and it's good. That's the one I found that was cooked/broken. Q14 (the small transistor above it) seems fine too. Thoughts on why it might not be firing beyond that? Not sure how to test/check it... I've always replaced the transistor and/or coil and boom it works.

I have a logic probe (haven't really needed to use it much though so I'm pretty new at it), and no test ROM... are you referring to the ones mentioned by pincoder? It looks like, per the schematic, Q15/Q14 go through IC1 7408 and the PIA marked IC5.

Also, I did check and both solenoid wires do have continuity back to the board... I was hoping that might be the cause, but nope.

I've got a bunch of 2N4401's from another repair, so I'll change Q14 too for good measure even though it tests good.

So if I was just going to replace the chip, you mean the IC1 7408?

Okay, I'll try Q14 and see if I have any luck. I tested from the coil wires back to the board, and it's got solid continuity. I reflowed the pins on the headers, but I haven't done new connector pins yet. Maybe I'll re-pin the specific pin associated with this coil, just for the hell of it. Going to do them all eventually anyway.

I replaced Q14, and was about to put the board, back, but decided to test Q15 again... and it was bad! I have a feeling the incorrect coil someone installed (which was bad, burned and simply not supposed to be there) may have caused the issue. When I originally replaced Q15, I tried the game out with no luck. I had not realized the coil itself was bad at the time, so I'm guessing that it caused the new transistor to fail.

So I replaced Q15 again, and this time used the knocker coil (which was detached anyway) to replace the bad outhole kicker coil (same coil). And sure enough, it works! So now the game will start and kick out a ball, play through and game over properly. Sadly, the magnet stopped working, so I'll have to look into that.

Current Issue List:

- No Sound During Gameplay, however sound test button on sound board causes all sounds to play properly
- Displays P1, P2, P3 and Credit are not displaying properly (partial segments or dead). P4 is okay.
- Still waiting on my new 6800 chip
- Magnet no longer triggering when switch is hit, however when I ground the transistor on the board, it does work
- Right Slingshot kicker not firing when switches are hit, however when I ground the transistor on the board, it does work

I'll check all of that and report back.

Regarding the displays - it's really strange. If I put the P1 display in P4 position, it still has the same issues. However, if I put P4 in P1 position, still has the same issue. Very strange. I am worried that the driver board is killing displays in that position some how. Thankfully putting P4 back made it work again.

Answering some of your questions after testing:

No, oddly enough it isn't now, so I will check the switch closer and see if it's dirty or having issues. The Magnet DOES activate during the Solenoid test, so it is still functioning.

Does [the right slingshot] fire in coil test?

Yes, it does

Does the coil test make sounds for coils 9-13?

When I cycle through the solenoid tests, no sounds are heard at all. It just fires the respective coils. Does solenoid/coil test mode normally include sound effects?

9-13 don't do anything sadly

1-6 fire as they should
7-8 are "N/C" and not used from what I can tell
9-16 nothing happens
17-19 are the Pops
20-21 are the Slings
22 is "N/C"

So I get the sounds with the sound board test switch, but not during the 9-13 in test mode. Thoughts? Thanks

I checked the switches in switch test for the magnet and the right sling, neither are registering. I'll have to look closer at those switches and wiring later today.

Regarding the sound situation, does the fact that I'm getting nothing during test on solenoids 9-13 indicate a chip issue? I was planning on replacing the 7408 if the outhole didn't start working, but now it is so I'm not sure if I should go that route. 6800 should arrive soon, but I don't know if that could be part of the problem?

The wiring for the coin lockout and knocker we both cut when I got the game (pretty common I've found some the lockouts can sometimes get noisy and people detach them I've found. The knocker coil I stole to replace my bad outhole coil, so I don't have one there to test right now.

I grounded the tabs on the transistors for a bunch of the coils the other day, and many of them did nothing (I'm guessing in the 9-16 range), but I'll double check that and see. Would grounding then cause the sound to play?

Okay I'll test it and report back ASAP. Could the issue be chip related, or are you thinking just wiring?

Grounding those transistors didn't do anything, so no luck there. I already reflowed all the headers on everything CPU/Driver related, but not on the sound board, so I could try that. Though would the sounds play using that test switch if those connectors were not working properly? I could always start repinning connectors, though it seems odd that all the sounds would be non functional together at once like that.

You can also ground the resistors on the sound board (R5-R10) to test the sound board sound inputs while bypassing the connectors

Could you elaborate a bit on this test? Do you mean use the same ground I was using on the solenoid transistors and connect it to one side of the sound board resistors? Not sure what you mean, so I don't want to blow anything by grounding something I'm not supposed to! Thanks

EDIT - I just tested for continuity between the Driver board connector 2J9 and the Sound board connector 10J3. All good. I extended that and tested from the Q33, Q35, etc. transistors, and they make it all the way to the 10J3 connector as well, and even tested past that to the resistors on the sound board, finding continuity. So I'm thinking the wiring/connectors are good. Thoughts?

Sidenote: Regarding the right slingshot not working, I decided to test continuity between the switch (Orange-Green) and the driver board. It was good to the connector (2J13, Pin 8), associated resistor (R5), and associated IC (IC7 Pin 12). Mystery continues. After doing the continuity testing, suddenly the right slingshot is working. Perhaps I fixed something that was loose or shorted.

I tried it... didn't hear anything. Is there a specific time I should do it (Game Over vs. Test mode)? If not, then I haven't had any luck as far as I can tell. So the test switch doesn't really help much, since it will still play sounds even if there are issues with the IC5 or PIA? Interesting. So rather than thinking the issue is over on the Driver or CPU, you're thinking Sound board then, based on your post.

.

Additionally - I did more switch tests, and it looks like all of the 3rd column in the switch Matrix (Green-Orange) isn't working. Column 6 (Green-Blue) might be out too... I need to check that. Last time I ran into that it was just a transistor, hopefully I get lucky and it's that simple.

I believe IC10 is the PIA, and if I'm correct, sadly it's not socketed. I do have a logic probe, but I'm relatively inexperienced with its use, so guidance would be needed.

Two Side Notes/Questions:

1) The "DS1" switch at the top of the sound board, to the left of the test switch, do the dip switch settings on that matter? One of mine is "on" the other "off".

2) Good news! I was messing with the connector for the switches, and wiggling the Green-Orange wire within the connector a bit made all the switches work again (including the Pit magnet, and drops). So I'll re-pin that connector and we should be good there.

I just found out Fuse F1 on the Sound Board was blown. Thought I checked both, but it's definitely no good. Rummaging for a 4A slow blow right now.

EDIT/UPDATE - Replaced the fuse... no change strangely. I'm thinking I should pull this board and reflow all the connectors, repin it as well.

A few questions if you don't mind... setting on the probe (CMOS/Pulse?) and if I remember correctly, I need to hook it up to a Ground and +5V?

UPDATE: So I did as I said above using the TP on the sound board. Pin 4 on IC5 just constantly showed "1" (High I assume) and no change really when I grounded R9. There was a very, very slight flicker of low maybe, but the 1 stayed on constantly red on my probe. On Pin 13 of IC6, same thing, only always "low" ("0"). I could be doing this wrong of course, please let me know if so. I did notice that there is a very small amount of static buzz that happens for about 1/2 second when I ground the R9, coming through the speaker, like it's trying to do something.

Here's something that could be important - I never tested the voltages on the Sound Board before. I just did using the Test Points on the board. The +5V is good (reading 4.97VDC), the -12VDC is showing a little high (-13.30VDC). My concern is that the +12V is showing low at 9.97VDC. Could that be the issue?

I just changed both the DS1 switches to "ON" (previously Switch 2 was ON and Switch 1 was OFF) and I'm getting some sounds now. I started a game, and got several "thud" sounds before the ball kicked out. I tried several targets and switches, and they all emitted a simple "tone" when triggered. Not the normal sound effects the game should have, but it's something and I didn't have that previously. I can make a video if it helps, let me know.

"The sounds all work in the sound test though?" - Guessing you mean when I press the sound test button? Yes, they all sound like they work to me. It cycles through a bunch of them, then all the Gorgar voice lines, without issue.

I had to stop testing for the evening since my whole family went to bed, and apparently the volume control pot is stuck on the current volume, which is loud (turning it in either direction does nothing). I'll see if I have a spare to replace it with.

I believe the simple notes thing you mentioned is indeed where I'm at after changing the DS. I'll mess with it some more in the morning and let you know. I'm re-pinning the switch connector before bed.

By the way, shout out to Rochester, I went to school there years ago. My sister still lives in the area.

Interesting update...

So today I took out the Sound/Speed boards and reflowed all the headers. I re-pinned all the connectors as well. When I reconnected everything, my sound was completely gone (no speaker hum, test switch on the sound board didn't do anything anymore). Then I touched the volume pot inside the cabinet, and just my fingers touching the metal dial made the whole system "buzz". After messing with the cabinet volume pot for a while, suddenly sound game back very quiet, with heavy buzz/hum. Turning the volume up or down changes nothing.

I started a game out of curiosity, and I actually had some in-game sounds. Gorgar speech worked when I triggered the magnet, and switches/targets produced a sound. It seems like all targets (behind rubber switches, rollovers, stand up targets) all make the same sound right now, but it's something, and Gorgar is talking a bit. Sound test switch still does all the sounds/speech like before. Thoughts?

The volume pot in the cabinet definitely looks like it might be an issue. It's labeled "1000 ohm", but tests as 2000ohm. And I thought these games used either 5kohm or 10kohm? I have a spare 10k, but I'm pretty sure that's not going to work. Can someone tell me what the correct potentiometer value would be?

After removing the 10J4 connector from the board and Jumpering across pins 1 & 2, I get max volume as you noted. So the volume issues are definitely the pot, which is fine I'll replace that once I know what the proper value is for it.

I'm getting the following now during gameplay:

- Gorgar does not speak when a game is started. Instead, there is a "pew pew pew pew" sound effect before the ball kicks out.
- Heartbeat sound effect working (which changes and speeds/slows during gameplay)
- Gorgar's voice works when the Pit is triggered
- Sound effect for the A+B+C rollovers x bonus award when all three are triggered sounds correct to me
- All other switches/rollovers/targets seem to share a single sound effect currently (sort of a buzzer sound)
- The only exception is one slightly different sound for the switches behind the drop targets.
- Spinner/Pops have no sound effect
- No sounds are emitted when the ball drains and bonus is counted

I haven't re-pinned the connector on the driver board, I'll do that next just in case.

I will PM you a link to a short video for reference.

Thoughts?

In the coil test, I now get sounds on 9 and 10, but nothing on 11-13. The sound I have for 9 is the sound I'm hearing for just about everything right now (switches, targets, etc).

I re-pinned the connector on the driver board. Now I get a sound at 13 as well. Still nothing on 11-12 though.

Grounded the transistors, and it matches what the coil test is doing. I get sound on Q31, Q33, Q39 ... Nothing on Q35, Q37, which correspond to 11 and 12.

Not sure what you mean? Continuity? Or logic-wise?

I'm also wondering why everything seems to be playing the same sound effect. I would think that if something sound-wise wasn't working, it would just play nothing, but instead they almost all sound the same.

10J3 Pins 4 & 5... grounded them, no sound. Also tried the corresponding resistors, same result. I checked continuity, and it's good from the transistor all the way through to the sound board, and associated resistor, so it looks like connectivity is good. Sounding more and more like a chip issue on the Sound Board?

Okay, here's what I got. My probe setup was: CMOS - PULSE - Clipped to +5V/Ground

10J3 Pin 2 goes to IC5 3->2 = Probe shows High ("1") solid lit before grounding, and when Pin grounded the light goes out
10J3 Pin 3 goes to IC5 5->4 = Probe shows High ("1") solid lit before grounding, and when Pin grounded the light goes out
10J3 Pin 4 goes to IC5 11->12 = Probe shows High ("1") solid lit before grounding, STAYS SOLID on when Pin Grounded
10J3 Pin 5 goes to IC5 9->10 = Probe shows High ("1") solid lit before grounding, STAYS SOLID on when Pin Grounded
10J3 Pin 7 goes to IC5 14->15 = Probe shows High ("1") solid lit before grounding, and when Pin grounded the light goes out

So the two items that do not have sound (Pins 4 & 5), also have different behavior on IC5 than the ones that do have sound when grounded. Not sure if I tested that correctly, but that's what I did, and those were the result.

Sorry for my lack of logic probe skills and terminology. Feel free to correct me!

Basically nothing happens on either pin associated with those sounds/transistors/connections. And I know I have continuity to everything, so I guess that makes sense. So order that chip (4050 Buffer), socket, and replace and see what happens?

Thanks zacaj

Ordered CD4050 non-inverting IC Buffers and some sockets. Under $7 shipped so I can't complain... but I do have to wait until next week sadly.

Pincoder provided a bunch of info/thoughts, should I run around with that too, or just wait for the 4050 buffer and do that before going too crazy? I can work on cleaning the game and maybe trying to sort out the display issues in the mean time I guess.

Displays are the other major issue. Not sure what to do there, but if it's bad I might just invest in a new set since they're not crazy expensive. Not sure where to start on those; I've fixed bally displays before by reflowing, etc, and some System 11 display repair, but these I'm not sure about. I have a feeling the master display board is in trouble. I see some cooked resistors I think. I'll have to look closely, take some pics, and share.

Everything else I think is relatively minor... here's a basic list I have going:

- Adding batteries causes the game to get stuck in audit mode. Taking them out and using on/off quick trick gets game to go into attract. Will order NVRAM to eliminate this issue.
- Volume Pot is bad, need to replace. Need to know proper value for replacement.
- Credit switches both disconnected, but can me manually jumpered to add credits. Will repair.
- GAR drop targets don't always register and are a little sluggish (cleaning needed)
- Knocker coil disconnected (removed coil and used it as outhole coil, which was the wrong coil when I got the game)
- Left pop bumper a little sluggish, will clean/adjust
- One-way gate entering play from shooter was missing, just got that in the mail and it's fixed
- Magnet trigger switch needs to be pressed in pretty far to trigger, will adjust
- Memory protect switch on coin door disconnected, but wires twisted together and all seems okay, figure I'll leave that alone for now.
- Power Supply is original, will rebuild it, although all output voltages are currently good, so I will wait until I fix sound/display first.

Some other things... but that's off the top of my head.

Just did some swapping around... interesting results:

Before Swapping

- P1 Display bottom segment and upper right segment out
- P2 Display same issue as P1
- P3 Dead
- P4 Working perfectly

Swaps/Results

- P3 Display Dead at all connections
- P4 plugged into P3 cabling, works perfectly (so P3 cabling and output is good!)
- Plugging P3 or P4 connector into P2 makes P2 work, so display good. Something is either wrong with P2 cable/connector or master display output for P2
- Plugging P3 connector into P1 display made it work, but bottom segment flickered
- Plugging P4 connector into P1 display similar results, but bottom segment almost completely out
- Plugging P3 or P4 (known good displays) into P1 connector causes same issue (missing bottom/top right segments)

Conclusions:

1) P2 and P4 Displays are Good
2) P3 and P4 Cabling/Connectors/Output are Good
3) P3 Display is Dead
4) Some sort of Problem with P1 and P2 cabling/connectors or Master Display output for those two displays.
5) P1 Display is likely damaged due to issues with Master Display Output?

EDIT - The fact that both P1 and P2 are missing the same segments makes sense. Checking schematic, they share the same path through the board for the same segments, using R2 ("b" segment) and R4 ("d" segment), then through IC9 pin 12 and 17 respectively for each of those segments.

Adding pic of R4 (4th from the left)... looks cooked.

Master_Dispaly_R4 (resized).jpg

Haha! Good point. I might end up needing all new stuff anyway. But I should be able to sell all the working parts from mine I guess, to help pay for it. I'll replace those resistors and see what happens!

I had (3) spare 10k ohm resistors, so I replaced R2, R4 and R5. R11 is showing 16kohm resistance and needs replacing, but it's semi-functional as-is so I had to leave it for now.

I reconnected everything and turned it on - all the Displays worked... for a few seconds. Then the same segments started to flicker a little, and go on/off and then out. I checked the resistors, and they're still good, but I have this feeling that even though they were bad, they got that way because something else may have contributed to the problem.

Any suggestions? I'm worried if I leave the game on, it will just burn the resistors out again.

I found a separate thread that referenced the same issue I'm having, and the feedback was that one (or more) of the displays is likely bad/shorted, which can cause the resistor(s) to keep burning out and failing. Since I knew that my P1 display was flawed, regardless of where it was plugged in, I unplugged it completely. Sure enough, now there are no display issues. The display (which I'm guessing is shorted or something similar), was causing the issue and resistor failure from what I can tell.

So for now, I have moved my P4 Display to P1, and it's working well. My P2 Display is good now too, as is my Credit Display!

My P3 (which was dead) and my original P1 (which I now know was causing my board failures and issues) are unplugged.

The problem now is that sourcing two working original displays might not be easy. For now, at least I have Two good displays and Credit Display... so progress.

One is completely dead and the glass has a break in one corner, so I'm thinking de-gassed? The other (the original P1 display) I can sometimes see little "Sparks" near the pins inside the glass in a couple spots, so I'm thinking it's shorted inside the glass.
Probably no way to get to that sadly, but I'll look.

It's too bad these are so expensive to replace.

IC5 removed, new buffer chip arrives today, with a socket, so I'll install that as soon as it arrives and report back. If that doesn't fix it, what's next, PIA chip?

Haha, fingers crossed. Mail is due to arrive within the hour. I'm literally sitting here waiting for it!

Sadly, no luck. In fact, I lost the sounds I did have with the previous IC5 chip. I assume I got the correct one... but maybe not? I ordered a 4050 Buffer per the parts list. I was sent a CD4050BE . Wondering if that's the wrong chip? They said it was "non-inverting"...

The one I pulled from the board says CD4050BE too and looks original.

Thoughts?

EDIT - Just tried another one of the chips I got (I bought 5x just in case) and this time I have similar sound effects to what I had before, but speech is not working on the pit again. I have one new sound that I think might be correct (targets being hit), but things still aren't quite right. I put the old chip back in, and I get my original results. First new chip, zero sound in-game. Second new chip, one new sound, but speech is gone. I could keep trying chips, but this is getting crazy.

The Sound Test button on the board still provides all sounds and speech. Driving me nuts not figuring this out. Is the PIA the only thing left? Not sure where to go from here. We know it's not the driver board or CPU since disconnecting the incoming cable and grounding the pins doesn't produce the sounds. Would replacing the PIA and/or capping the sound board have much effect?

Interesting... I'm going to re-read this and see if I can pull that off and report back on the results. Since I have some extra 4050s, it's not a big deal if I screw up I guess. I'll triple-check my work too, but I'm fairly certain everything is making good contact and the socket was soldered in well. I always test things when I install sockets, but you never know.

As for the other post above, sadly since I have a modified System 3 board running all this, the chip is a 6800 and I don't think I can do that 6802 trick anyway. Just realized you meant the 6808/6802 on the Sound Board. Mine is a 6808 socketed.

If I end up ordering the new sound board PIA, I'll probably grab a few other ICs from the sound board as well, just to have them in case I have to keep replacing things to try and sort this out. Hard to believe it's still giving me trouble. But at least I know the CPU/Driver aren't the issue at this point thanks to all the testing zacaj has had me do!

Looking at the schematic, I just want to make sure I'm reading your suggestion correctly. So IC5 pin 4, for example, would be bent out and I would test that and also test IC6 Pin 11 and IC10 Pin 10 ? And I would be looking for all 3 pins to have the same reading when tested like that? Then do the same for all the other IC5 pins you mentioned and their schematic-related pins on the other chips?

Cool, thank you. I will try this in a bit and report back. I really appreciate the time and effort you're putting into helping me with this - and don't worry, I pay it all forward!

Okay, so I ran a bunch of tests. First thing I noticed that I think is important is this:

1) When I had IC5 legs 2, 4, 10, 12, 15 all bent out, I tested each leg with the probe. All read High, and when I grounded the associated J3 pins, they went low as expected. I checked their voltage readings too, all show around 4.9VDC.

Then I did the same test with IC5 fully inserted, no legs bent out. The same results except for IC5 pin 15 which didn't register on the probe as high or low. I grabbed my meter and checked all the voltages on the same legs. They were all 4.89VDC except for Pin 15, which was reading only 2.60VDC. I checked its partner pin, Pin 14, and it had 4.89V. They're supposed to match based on what I've learned from you, so I figure that's NOT good. So for some reason, when IC5 is fully inserted, something goes wrong with Pin 15. I checked this twice, using one of my new chips and the original, same results on Pin 15. It DOES go low when the associated J3 Pin 7 is grounded.


2) I also did all of the tests you suggested, and here's what I found:

With Legs 2, 4, 10, 12, 15 bent out, I tested the associated IC6 and IC10 pins as suggested. They all read High, except for IC6, Pin 10 and IC10 Pin 14 - which are linked, and associated with IC5 Pin 15. I found no reading at all on them with the probe, and testing them with the Meter, I got 0 VDC.

Here's a weird thing - the associated J3 pin (Pin 7) actually produces a sound when grounded, despite the above strangeness.

Thoughts?

Double-checked voltages with IC5 fully inserted, and I noticed that IC5 Pin 12 is a little low at 4.09VDC. 2, 4, and 10 are all 4.89VDC. Not sure if that indicates anything strange with Pin 12 as well, or if that's acceptable.

It makes sense what you're saying about something pulling it down. Since Pin 14 and 15 of IC5 both show ~4.9V when the leg is out, and then suddenly Pin 15 drops to almost half that when inserted while 14 stays at ~4.9V, then clearly something is off there. I'll go ahead and remove IC6 and 10 and pull IC5 from the socket again and do those tests when I can sit down and desolder everything. I guess I should go ahead and just order the chips and sockets too. They're not that pricey and I'll want to socket before putting anything back together either way.

Yes, it's set to 01. I've actually had the heartbeat sound most of the time, so that's working okay during gameplay.

zacaj - I ordered all the chips/sockets/etc. I'll start taking the existing chips out and do the tests you suggested over the next day or so. Everything should arrive by this weekend I believe, so I'll hopefully be able to get this up and running soon. Fingers crossed either IC6 or IC10 solves this! I've got a capacitor order ready to be placed too, figure if this next step doesn't work, might as well cap the sound and power boards since it's not pricey to do it and it's simple work.

Small update - Still waiting on parts for the sound board, but in the mean time I decided to strip the game down, clean it, replace the rubbers/bulbs, and give it a nice waxing. Also took apart the drop target mechs, cleaned everything up so they make better contact and drop smoothly. In the process, I found out they weren't making great switch/wiper contact. After cleaning and such, the game plays better. Now when all 6 drops are down, Gorgar actually speaks like he should saying you hurt/beat him, etc. Pretty cool.

More to come as soon as I get those parts!

Edit: Adding a pic for the curious. This was just before the final cleaning/waxing I believe.

Gorgar_PF (resized).jpg

Interesting, thanks mof! I'll have to check those out during gameplay. Your game plays really fast and snappy. Curious what your slope is, approx? I need to make some adjustments, as mine is only around 5.2 degrees or so right now, and I'm guessing it should be in the 6-7 range somewhere. I haven't rebuilt the flippers yet (figure I should get the sound fixed first), so they don't play as snappy as yours just yet.

Sound Fixed!!!

Socketed and replaced IC10 and IC6 today (after testing as zacaj suggested and finding no resistance issues, etc). Sound works perfectly now! Not sure which it was, but I have this feeling it was the NAND gate (IC6). I'm not going to swap around and find out, I'm happy with it working.

Thank you to everyone for their help, especially zacaj for his repeated advice and assistance through all the posts in this thread. Many thanks!

Now I need to find a couple of 6 digit displays (or go LED), rebuild the flippers, and I should be set. mof , I played a few games and sure enough noticed what you mentioned about those posts/lanes. Seems like one side is worse than the other on mine. I'll have to take a look. I assume you rebuilt your flippers - did you stick with original coils and just do a standard rebuild kit?

Going to mark this thread as solved, and start another if anything else pops up. I can't say it enough - thank you all.

Me too, I was just curious because your flippers in the videos were sharp and strong, they looked great.

Thanks for your help too frunch, as always.

Nooooo! The sound just stopped working again! zacaj I'm not sure what happened. I played maybe 20 or so games, perfect sound. This morning, started a game, and all it said was the "Gorga..." (rather than the full Gorgar Speaks line) and then all sound died. Ball kicked out for play, but NO sound is working now. When I press the test switch, all sounds are still good. What the heck happened? Is it possible something just killed the chip(s) again? Maybe I should recap this whole thing in case my voltage tests aren't solid enough?

Argh.

Edit - came back a few minutes later, tried another game, sound worked for about 10-15 seconds and then went out again. Come on Gorgar... cut me some slack.

I only changed 2 caps so far on the sound board. I have the rest sitting in my GPE cart. Think I should go ahead and do that? Wasn't sure if that could cause it.

Okay, I'll order those and the power supply ones too for good measure. Generally money well spent anyway, and not tough to do.

As for chip swapping, the IC10 PIA I only bought one new one of since they're $9+ each. IC6 NAND was $5 so same thing. I could swap in the old ones one at a time, but I know at least one of those two was bad so I don't know if that's a good idea!

Just turned it back on, ran it through the solenoid/sound test on the coin door and everything was fine. I left it on one sound effect for a minute or two looping just to see if it would cut out, and it didn't. So I started a game, played several minutes, the sound stayed on just fine. Looks like I have an interesting mystery.

Only thing I did since getting the sound to work was put batteries back in. I had trouble with those before, and had to use the on/off trick with no batteries installed because whenever I had batteries in, the game was stuck in audit. That's no longer a problem all of a sudden, because the game boots to Game Over now with batteries installed and remembers the high high score and credits.

As for chip prices... To be fair, I was ordering stuff from Marco and got them there... probably cheaper other places for the NAND at least.

I actually realized that the IC5 buffer chip I put back in the socket is the original. Since we figured out the problem was downstream from that, I simply put it back in. I guess I could try one of the extra buffer chips I bought (I have 5) but I doubt that will change anything. Maybe I'll pull all the chips and test like you said, see what I can figure out.

pincoder I'll send you a message - I don't have access to a nearby burner, the closest one I know that a friend owns is 2 hours there and back driving, so it's likely cheaper to have you send me one!

Removed the batteries, played several games, sound still going. Not sure if it was related, who knows. I'll give it a little more time and see what happens.