Another dead Memotech - Can it be saved ?

About original Memotech hardware.
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Crazyboss
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Another dead Memotech - Can it be saved ?

Post by Crazyboss »

Yes another dead Memotech, not sure whats the story about this. Not sure if this board will be saved or for parts only, for sure some traces have to be fixed, and even that maybe there is a serious shortcut somewhere at the board causing this burned pcb.

VDP looks bad, but ....
VDP looks bad, but ....
burnmtx1.jpg (164.11 KiB) Viewed 4417 times
one PIN is bend, Not sure if it can be saved, but else need to solder a "new" PIN there.
one PIN is bend, Not sure if it can be saved, but else need to solder a "new" PIN there.
burnmtx2.jpg (133.22 KiB) Viewed 4417 times
EPROM looks very bad, looks like something have shorted the pins leaving a mark there.
EPROM looks very bad, looks like something have shorted the pins leaving a mark there.
burnmtx3.jpg (78.33 KiB) Viewed 4417 times
Very bad shape.
Very bad shape.
burnmtx4.jpg (69.54 KiB) Viewed 4417 times
Looks like somone soldered here with a HAMMER?
Looks like somone soldered here with a HAMMER?
burnmtx5.jpg (109.79 KiB) Viewed 4417 times
More HAMMER soldering.
More HAMMER soldering.
burnmtx6.jpg (200.73 KiB) Viewed 4417 times
Removed all the diodes, and tried to clean up the PCB, broken and burned traces.
Removed all the diodes, and tried to clean up the PCB, broken and burned traces.
burnmtx7.jpg (106.12 KiB) Viewed 4417 times
I think this MTX can be saved but not sure its worth, maybe this one will be for parts.
I think this MTX can be saved but not sure its worth, maybe this one will be for parts.
burnmtx8.jpg (167.96 KiB) Viewed 4417 times
//CLAUS - Webmaster at www.mtxworld.dk
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Dave
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Re: Another dead Memotech - Can it be saved ?

Post by Dave »

The short answer is, YES, it can almost certainly be saved.

The real question, is, is there any point? I would usually say that it is always worth saving an MTX, but if you just have the bare PCB, without the case, particularly the keyboard, and without the power supply, there is probably little to be gained by spending a lot of time on this board. If a complete MTX fails, then it would likely take less effort to repair than this board. If you have a lot of free time though, then I suppose that it would be a nice challenge to get it working.

I would just keep the board in its current state in case I ever needed a bare board, at that point, I would work on it. In the meantime, I wouldn’t rob it for parts though.
Martin A
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Re: Another dead Memotech - Can it be saved ?

Post by Martin A »

The bent pin should be saveable, if you go slow and steady with the pliers.

With the board already modified to take the 2564 EPROM, if you DO decide ressurect it, then making the extra changes to fit a slightly more modern (ie only 35 years old) 2764 EPROM (or even newer 27C64 or 28C64 EEPROM) might be an idea.

Though if you want to stick with the 25xx I've got a 3 rom set of 25xx's here of unknown quality if you want em.
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Crazyboss
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Re: Another dead Memotech - Can it be saved ?

Post by Crazyboss »

I did a bit more testing, it seems like the Z80 and the VDP was dead, i checked the parts in another memotech. But the CTC. The VDP got very hot very fast, so I guess it was shorted.

The pal board kind of work but gives gray scale picture, sometimes i get colors, but weird bars and sometimes some red shadows. I checked the service manual, but didn fix that. So for now that memotech board is in the parts-bin. I guess the 2564 roms, are the same kind they use at the C64, I saw someone did an adaptor. But i guess there might not be space for that, but right now that mtx board is the last on the list to be saved.

It acutally came from a complete memotech, so I have the case, keyboard etc. The keyboard is very bad too, 5 keys dont give any thing, some started to work after some time.
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