Dig Dug Garbage at startup

wantdataeast

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I pulled every single socketed, ic chip and carefully cleaned each leg cleaning both ic's and sockets with Deoxit.

Getting this garbage on screen at startup.
 
Check your +5 voltage at the board and the AR2.

Maybe swap out the CPU if you have one.

Jason
 
I was getting the RAM 0L error prior to clean the IC legs. It went away on my last bit of start ups, but now is back

So I am getting the RAM 0L at start up which according to my manual (TM-203 4th printing) indicates bad RAM at location 4K which in my manual is marked 137211-001 mine current chip is marked TMM2016P.

Is that a likely / possible culprit for my startup problems?

Also, voltage at the AR-2 board it 12.25 VAC and I am getting 5.08 VDC on my MPU(tested from legs of one the 74LS chips)

-New Big blue installed on power brick
-rebuild kit installed on the AR-2 board.
-toasty bifurcated contacts pins replaced at edge connector
 
IMG_7685.jpeg

As it turns out, I had what arcade shop calls a compatible ram on hand. I put it in and I'm still getting same RAM 01 error. That indicates this ram chip at 4K is bad. (again it's brand new ram.) and now I'm getting a ROM 1 error as well. Indicating that I need to replace a ROM at 2 c/d

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1743723109522.jpeg

I'm having a hell of a hard time believing that this brand new ram chip that I just installed at 4K is bad.
 
100ns may be too fast for Dig Dig...
There's really no reason to 'waste' a low power CMOS RAM on something that's not battery backed anyway.
 
Personally, I'd never buy chips from Arcadeshop. Very hit and miss. APAR has been 100% reliable for me when it comes to chips. Cosmetic stuff and switching power supplies are about all I get from AS anymore.

Jason
 
RAM 0L is the very first ram in the test. If it isn't actually the RAM (which swapping them around proves usually) then it is a supporting chip that provides access to it.. A couple of times on that board (for me) it was LS32 @1E - but it can be a lot of things on DD..
 
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Is there a chance that the ROM 1 error is causing the RAM 0L / HL error . I realize it's not the same but garbage on the screen on say a Pac-Man machine sure looks a whole hell of a lot like this. I don't mind throwing a LS 32 chip at it at the 1E position. I have those in stock.
 
I'm not saying the LS32 will fix it, it has in a couple of cases for me.. If you can see errors on the screen, then some code is executing..
There are a number of chips between the CPU and the RAM that can be part of the issue.
A logic probe or scope or other diag tool would be needed to know for sure.
 
Personally, I'd never buy chips from Arcadeshop. Very hit and miss. APAR has been 100% reliable for me when it comes to chips. Cosmetic stuff and switching power supplies are about all I get from AS anymore.

Jason


While you're 100% correct about Arcadeshop's components, that's an old Great Plains Electronics bag. Nice to see one of those labels again.

Ed's stuff was solid. Too bad he retired, I used to love ordering from him. Best packing jobs in the business. And his site (which still exists) was exceptionally well organized.
 
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