System 11B CPU board, please help!

AE35

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Hi all!

This is the last day I'm working on my System 11B CPU board from my
Earthshaker....then I'll give it the fire axe(or my wife will) and order a
reproduction.

I don't even know where to start. The board started with being flaky, sometimes
booting, sometimes not. When you played for a while the game would freeze with
a bright burning segment on the display.

As of now, I've changed the PIA U41, the blanking 555 and transistor, the CPU's, the
74154 and checked resistors at R55 and R56 and changed the caps at C30 and C29

My PSU in the game outputs 4.95V, but when checked on the board it's 4.92-ish.
When running the CPU board on the bench, with a PC power supply, the voltage
is 5.5V without load on the PSU, and when connected to the CPU board it's 3.9V or
4V. That's quite a drop. This is measured on the CPU U15 and the testpoint.

Changing that PIA was horrible and I've spent way too much time on this board:(

By the way, the board does have battery damage!

Thanks for your time, I really appreciate it!

Sorry for the blurry image! As you can see only the +5V lights up!
temp5volt.JPG
 
I have repaired a LOT of those battery damaged Sys 11 boards. The design left little room for repairability (of course, obsolesence is built in), putting many parallel traces UNDER the battery pack (which leaked in the direction that would cause the mmost damage). To boot, the traces are super thin, which leaves little if any connectivity left after the corrosion takes hold.

I would have offered to work on your board, but given it's alreday been worked on, I am shy to do so. Nothing against you personally, but once things are reworked, they are even weaker - and hide defects that take a LONG time to find. I recommend you save the headache and get yourself a new one....

Chris
 
Hi all!

This is the last day I'm working on my System 11B CPU board from my
Earthshaker....then I'll give it the fire axe(or my wife will) and order a
reproduction.

I will pay shipping to save it from that fate :p

I don't even know where to start. The board started with being flaky, sometimes
booting, sometimes not. When you played for a while the game would freeze with
a bright burning segment on the display.

As of now, I've changed the PIA U41, the blanking 555 and transistor, the CPU's, the
74154 and checked resistors at R55 and R56 and changed the caps at C30 and C29

Why did you replace all that stuff? Acid damage?

My PSU in the game outputs 4.95V, but when checked on the board it's 4.92-ish.
When running the CPU board on the bench, with a PC power supply, the voltage
is 5.5V without load on the PSU, and when connected to the CPU board it's 3.9V or
4V. That's quite a drop. This is measured on the CPU U15 and the testpoint.

That IS quite a voltage drop. If something is drawing that much I would expect it to get hot relatively quickly. Have you tried the old "feel the chips" strategy?

Changing that PIA was horrible and I've spent way too much time on this board:(

Yeah... that's always fun.

By the way, the board does have battery damage!

How bad? If it's bad you might as well fix that now too.

I would start with a test ROM and just the CPU. Get that booting and build out from there. That's easier said than done with boards that have soldered PIAs but I would start with as little as possible on the bus, get that stuff working then add the rest, testing as you go. If everything is locked up and it's drawing current like crazy something is dead, near death or possibly just plain screwed up from the repairs you've already done. Could be a RAM, PIA, etc... could be acid damage or could be a combination of a bunch of things.

The most direct approach is going to be with a test ROM and starting with the least amount of potential problems possible that could cause the CPU to not boot. Once it's running the test ROM you can test everything else. It sounds like a lot of time and effort but you'll find that a systematic approach to this kind of repair will be far more direct and effective than trying to solve the problem as one big chunk.
 
"Nothing against you personally"

I understand perfectly! extensive work was done on it when I got it...and
then I added repairs:)...and then it's just too much.

Any thought where I can get a new one? I just checked the Rotten Dog
prices...at 300USD that seems somewhat high.

I'm just frustrated that so many things seem to go so wrong....I read about
guys getting a 200USD defective Twilight Zone, and then "it was just the fuse"
Maybe that's a little stretched, but I never have the 'resolder header pins" fix
succes-stories

I just fixed a Xenon, and EVERY board was bad.....every one of them.

That's my sob-story:)
 
Boards with previous work - ACK! I am working on a WPC-89 MPU right now that had chips replaced for no apparent reason, including the ASIC socket. The guy who sent me the board told me he exchanged a working one for it (!). The processor was shot, the ASIC was shot, rework had been done, and a data line was shorted to ground through a '374. Five hours later, still not working.

Yeah, I feel for you. Sorry. The rule nowadays (after 11 years in the hobby) - most games/boards that are circling around WILL be in the worst possible shape, or will be populated with a bad boardset in every way. I recently did a Williams Stellar Wars like this -ALL the boards were bad. The pond has been fished really hard, and what's left is kinda slimy.

Not sure what to tell you. Wish I had a board I could offer. If you would like me to take a look at it, I'd be happy to.

Chris
 
Hey Lindsey! The test-thingy etc. is out. That is simply too much for me...I've
gone sour on the board. I'm not going to try and socket the remaining six PIAs:)
That would take me 4 days straight lol

Nothing gets warm...at all...

Chris, where are you in the world?:) I'm in Denmark.
I also have the horrible MPU from the Xenon, and the awful MPU
from my Bally Star Trek. It seems like you get to accumulate stuff in
this hobby:) I got a Tomcat home, that had water damage...I think I
made a good call parting it out; otherwise that would have been a
life-project too:)

I love Xenon, but had I known that it would take me a year to fix it,
I would found another machine.

My wife calls this my quitter-phase.
 
AE:

I am in Texas, USA. Don't I know about collecting! Over the years I have been in several warehouse raids, and took a LOT of stuff home. I have used boards of all types, extra games, factory testers, hundreds of coils, miscellaneous parts. It gets crazy - I have really tried to thin out as time goes by. Don't own any dedicated vids, but I do have a Pole Position waiting for me in storage. I also had a Galaga and Kangaroo at one time, and knew a lot of the local vid guys.

Funny part about my Xenon - it is a re-import, as is my Centaur. You guys have good stuff!!

I saw your ".de" suffix and figured you were in Europe. Quitter phase? In pinball there is no quit - it's all about the suffering...lol.

Chris
 
I once sent a previously reworked board to Coin-Op Cauldron. It was returned with a tag that read "Faults in previous repair". Nothing more, nothing less, no suggestions, no recommendations, nothing.

While nobody else has ever told me that this has happened to them, I believe it still worth mentioning because it applies here. I truly believe they would not touch this board, and I'd sure hate to see it sent the whole way from Denmark to be turned around again without resolve.

I can't speak for what Ed would accept or not, but he certainly knows his stuff!

Chris
 
i have a few wpc- 89 boards chris

im also getting some nos asic chips

and ive been accumulating components to bullett proof wpc boards

one thing i dont have and is the BANE of my existence.....i dont have any wpc sound boards


ae, i HAD a set of sys 11 boards that worked but my buddy scarfed them pretty quick!

being that your in over the water id recommend the rottendog, at least it has a good warranty...
 
I can see that Ed Cheung sells them too, I'll shoot him an email.

If anyone else has one lying around, let me know:)
 
I can see that the british reseller of the Rotten Dog boards only
want a little more than 400USD for a System 11 reproduction board. Lol
Then add shipping.

I'd rather put the machine into storage than pay that. That's ridiculous.

http://www.pinballdisplays.co.uk/
 
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