Williams Defender Video/Sync issues

I was just fixing a Defender board the other day and I ended up replacing the 7474s at 3J and 3L. I had a good 12Mhz clock but no CPU clock. Board was watchdogging. The clock was getting lost between the 2 7474s. I was in the same state, no video and all 4 LEDs were on solid.

YMMV
yes, that's why I always suggest replacing those first lol

Ken Graham wisdom years ago indicated that they were pushed to their limits. except now they're over 40 years of age, not just 30 years, so it may happen more. I find it intriguing how many of these games just had 4116s swapped around 800 times and the rest of the boards are still untouched otherwise.
 
32 is High all the time? Are you seeing any other activity on the CPU? Address lines, Data Lines? What do you see on 34 and 35?
Yep, It is not budging stuck on high and the data/address lines pulsing
 
I have my JAMMA adapter rigged up to use composite sync. and I added a 7404 to it in order to make it negative sync. it was an experiment I did tapping my JROK TV encoder into it. lol the composite sync pin of the video header is the NC one in the drawing set. but everyone be mindful these output positive sync natively. there's a jumper on the board you can change to make it negative sync but that's obviously not practical for my needs tapping in different boards.
Yes, I have my experimental jamma adapter with a 7404 but considering just adding the circuit for complete conversion since some of williams boards were not consistent with their sync design. This way I can make a standard on my adapters for any williams board.
 
I was just fixing a Defender board the other day and I ended up replacing the 7474s at 3J and 3L. I had a good 12Mhz clock but no CPU clock. Board was watchdogging. The clock was getting lost between the 2 7474s. I was in the same state, no video and all 4 LEDs were on solid.

YMMV
I wish that was the case for me.. The clocks are all good.
 
I wish that was the case for me.. The clocks are all good.
Too bad it was not something easy there. Brad is right about not randomly replacing parts, need to find the part(s) that is preventing the program from
running.
 
Too bad it was not something easy there. Brad is right about not randomly replacing parts, need to find the part(s) that is preventing the program from
running.
I took that to be in reference to me suggesting replace row 7 7474s. which is fine. whatever. 97% of all games that had no CPU reset I found the 7474s to be bad. it's been a long time but I'm certain I was able to deduce this by piggybacking. out of all the boards I've fixed that had no CPU reset I think I only had one where one of the reset transistors was bad. and about a couple months ago I had one of mine with an actual bad 6809.

if nobody wants my insight from my past experiences fixing games then stop tagging me in your threads and PMing me. I wasn't aware this was a contest to see whose knowledge of the Williams force is the strongest.
 
I took that to be in reference to me suggesting replace row 7 7474s. which is fine. whatever. 97% of all games that had no CPU reset I found the 7474s to be bad. it's been a long time but I'm certain I was able to deduce this by piggybacking. out of all the boards I've fixed that had no CPU reset I think I only had one where one of the reset transistors was bad. and about a couple months ago I had one of mine with an actual bad 6809.

if nobody wants my insight from my past experiences fixing games then stop tagging me in your threads and PMing me. I wasn't aware this was a contest to see whose knowledge of the Williams force is the strongest.
Oh, Mecha I do really appreciate your experience and knowledge of these boards very much so keep spilling out as much knowledge as you can because there isnt that many of us left to bring these guys back to life anymore.
Also, I am one of those tech/engineers that want to not only see stable operation of these boards but be able to hang in there for another 15 to 20.
 
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Do you have a spare 6809E you can throw in there to rule that out?
Yes already did that.. It is weird for sure since some of the SA for the defender isnt complete I am not sure if its a correct sig in some areas I am checking even when comparing to the stargate signatures.
 
Update, I am moving on to another board that has some life with a continuous rug and looks very clean. I was pushing on the rams and the rug was changing a bit while I pressed on them.
After closer inspection... some of the chips would almost fall out when flipping the board over. So, for the moment I am replacing those sockets with newer dual swipes and installing the 4164s and see
where it lands after that. Ill post a pic of board soon. FYI this board will use the same rom board also.
 
Yes already did that.. It is weird for sure since some of the SA for the defender isnt complete I am not sure if its a correct sig in some areas I am checking even when comparing to the stargate signatures.
If it's identical hardware that you are testing, then I would say yes they would probably match.
 
I took that to be in reference to me suggesting replace row 7 7474s. which is fine. whatever. 97% of all games that had no CPU reset I found the 7474s to be bad. it's been a long time but I'm certain I was able to deduce this by piggybacking. out of all the boards I've fixed that had no CPU reset I think I only had one where one of the reset transistors was bad. and about a couple months ago I had one of mine with an actual bad 6809.

if nobody wants my insight from my past experiences fixing games then stop tagging me in your threads and PMing me. I wasn't aware this was a contest to see whose knowledge of the Williams force is the strongest.
I can agree with this as I to have this happen but in this boards case its not. I have had only one where some of the transistors had broke legs. Keep sharing the knowledge because not every board has the same issues I have found since working on these.
 
If it's identical hardware that you are testing, then I would say yes they would probably match.
I have to review my notes but I think that the decoder 74ls139 is where things have different signatures.
 
I took that to be in reference to me suggesting replace row 7 7474s. which is fine. whatever. 97% of all games that had no CPU reset I found the 7474s to be bad. it's been a long time but I'm certain I was able to deduce this by piggybacking. out of all the boards I've fixed that had no CPU reset I think I only had one where one of the reset transistors was bad. and about a couple months ago I had one of mine with an actual bad 6809.

if nobody wants my insight from my past experiences fixing games then stop tagging me in your threads and PMing me. I wasn't aware this was a contest to see whose knowledge of the Williams force is the strongest.
I have to echo how much I appreciate your knowledge. Reading your posts has given me deeper insight into the Williams hardware. Other than one cranky board, I have been able to fix all my project boards... the ones worth saving anyway.
 
Update on this ongoing saga lol 😆
Here is a pic of another board I pulled from the stack that had rams almost falling out of socket. I am currently replacing the sockets and putting known good 4164 in its place to see if that will get us past the endless rug before I start poking around elsewhere
 

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Those traces by the RAM look suspicious..
looks like a flux spill lol I would go over that with rubbing alcohol and toothbrush, should take it up

also the MPUs are interchangeable between Rev. B-Rev. D (BS.BA capable), it's really only the rom board that dictates what the game is. hence the importance of rom ribbon cable health.
 
So, I am just getting started on the Socket/ram replacement for this board, just wanted to get it out there to show the Serial and its current condition. Wow.. I did not know that about Rev D. Ill have to grab another rom card and try it out.
The Defender rom cards I have all of their sockets replaced and one has original roms that still work.
So just to clarify My PSU,s are in check for correct voltages and the rom card works on a known working MCU.
The issue that this board currently has is a continuous rug, but lets see what happens after some new ram installed :)
Ill post a new pic once I finish the ram update
 
So, I am just getting started on the Socket/ram replacement for this board, just wanted to get it out there to show the Serial and its current condition. Wow.. I did not know that about Rev D. Ill have to grab another rom card and try it out.
The Defender rom cards I have all of their sockets replaced and one has original roms that still work.
So just to clarify My PSU,s are in check for correct voltages and the rom card works on a known working MCU.
The issue that this board currently has is a continuous rug, but lets see what happens after some new ram installed :)
Ill post a new pic once I finish the ram update
wait. are you trying to run Defender? cause that only works with Defender boards. Stargate and later won't work. :x
 
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