Topic: Can't fix 'em all  (Read 2347 times)

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Offline Womble

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Can't fix 'em all
« on: June 06, 2010, 10:14:28 AM »
Seems like a guy I know has fallen for the "batch of faulty boards going cheap ruse", they are all landfill fodder, stuff thats been stored in a shed or garage for years. These places are generally just as damp as the outside world, either cold damp down south, or humidity damp up north. You might as well put the boxes out in the yard with an umbrella over them,  the effect is the same - corrosion.

Got an original Strider board which has all the signs of storage-in-a-shed, namely it is rusted to buggery, what's interesting is it is not obviously in bad nick at first glance. Rusted boards can sometimes be fixed but only if its in the very early stages.

When plugged in this board did nothing, I got the same scan lines on the cab screen that I get when I power the cab up without a board connected.

As its a CPS1 board it has a ROM board (B board + C board) and the motherboard (the A board). I have a few working A boards floating around so I put the ROM board on the new A board and fired it up. The game briefly started with major gfx corruption then black screened on me. Plugging a known good BC board into the rusty A board gave the same "no board attached" result, the A board is totally dead.

Started to pull the ROMS on the B board and the fault was obvious, the ROM legs are so badly rusted that they are no longer connected to the chips, the sockets are just as bad too.





Most of these chips are probably still working, until they are pulled for testing or disturbed. Then the rusted legs will just give way. So there is no way to test them as most will not survive being removed from the board. Most are so far gone they probably would not stand even the slightest vibration or knocks.

The A board has died a similar death, not only are a lot of the tracks under the laquer almost black with oxide the tiny pins on the large custom ICs are red with rust at the point where they enter the chip...



..these are much much thinner than the pins on an eprom so these probably died a long time ago.

The same goes for the TTL chips, Texas Instruments chips seem more rust prone on this board than any other type, but this chip is probably dead too.



The board probably worked fine when it went into its shed, sadly it was quite dusty which makes things worse, the dust gets damp and traps the moisture right on the board, just where you don't want it to be long term.

With a wrecked A board, and virtually every EPROM and socket on the B board ruined, there is nothing worth salvaging.

Also in the box was a bootleg Wonderboy, this does boot and sort of runs until the game demo starts, then it crashes. Although it runs the graphics are a mess and the screen is very unstable. The real killer is rust again, this time its mainly under the lacquer which tends to go unnoticed. In theory once the board is made and lacquered the copper tracks are sealed away from the elements, but it seems they are not totally protected from time and damp.



The good green tracks in this photo are obvious, as are the bad black ones, this does not mean they are open circuit, only that they are well on the way to failing. A fair few tracks I tested seemed to be dead, it can be hard to tell as the solder points are also pretty oxidised so getting the continuity tester to work can be hit and miss.

Either way, this board is covered in oxidised tracks that I could spend countless hours buzzing  through, if I managed to find all the bad ones the other 400 odd ones are all on their way to failing, so tomorrow, next week, next month perhaps, the board will fail again.

Once the rust starts there is no way to stop it, especially as it is physically larger than the track material it replaces so it cracks the lacquer off in tiny areas, letting the air in to make things worse.

Two boards scrapped, the same cause, storage in damp conditions, they were probably both working perfectly until they got relegated to the shed. It doesn't take long for this to happen either, think months rather than years.
« Last Edit: June 06, 2010, 12:08:25 PM by Womble »
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Offline porchy

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Re: Can't fix 'em all
« Reply #1 on: June 06, 2010, 01:02:57 PM »
its a damn shame that some people let boards get into this state.
those cps1 pcbs are a bitch to fault find on too

Offline Womble

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Re: Can't fix 'em all
« Reply #2 on: June 06, 2010, 03:37:23 PM »
Unless it's a no sound fault, 9 times out of 10 it's a dead Z80!
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Offline AndyRCM

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Re: Can't fix 'em all
« Reply #3 on: June 06, 2010, 09:37:41 PM »
arrrggghhh doesn't it anger you to see stuff like that - what a crying shame! :(

A
"I could see the faces of those who led pissing themselves laughing" - Funeral Pyre by The Jam

Offline porchy

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Re: Can't fix 'em all
« Reply #4 on: June 06, 2010, 09:40:38 PM »
arrrggghhh doesn't it anger you to see stuff like that - what a crying shame! :(

A
It sure does

Offline Womble

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Re: Can't fix 'em all
« Reply #5 on: June 07, 2010, 02:13:02 AM »
Bootlegs I have no great love for, usually very badly made, this one is no exception, also not a great fan of Strider either. Am happier to scrap it than to fight with it. I must admit I am losing my love for fighting badly damaged boards, also find fixing other peoples boards far less engaging than fixing ones I bought  myself. Possibly coz they sent god awful games to me, ones I would never even bid on.

I really dont get why Wonderboy is so highly rated.  ???
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Offline porchy

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Re: Can't fix 'em all
« Reply #6 on: June 07, 2010, 04:13:08 PM »
Bootlegs I have no great love for, usually very badly made, this one is no exception, also not a great fan of Strider either. Am happier to scrap it than to fight with it. I must admit I am losing my love for fighting badly damaged boards, also find fixing other peoples boards far less engaging than fixing ones I bought  myself. Possibly coz they sent god awful games to me, ones I would never even bid on.

I really dont get why Wonderboy is so highly rated.  ???

there are a lot of games that i own that i dont really rate that highly but they remind me of good times so get them for nostalgic purposes, Wonderboy actually being one of them. Paraphrasing on what you said, Wonderboy is quite pants

Offline AndyRCM

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Re: Can't fix 'em all
« Reply #7 on: June 07, 2010, 04:13:42 PM »
oooo I quite enjoyed Wonderboy . . . although it was the Amiga version I played . . . ;)
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Offline Womble

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Re: Can't fix 'em all
« Reply #8 on: June 08, 2010, 05:32:29 AM »
Torn between selling the one I just fixed, or keeping it as a worker for comparative purposes for future WB repairs. They are a decent cash cow if the faulty ones can be got cheaply enough. Can make between 50 and 100 quid on a WB repair, one of the very few boards where there is any money left.
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