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trs-80 model 1 video issue

tdog557

New Member
Joined
Aug 11, 2014
Messages
4
Hello everyone, I recently acquired a trs-80 model 1 that is in good condition. It was in storage for a very long time and theres an issue with it. When I boot it up, some of the characters on the screen are replaced with random ones and I get a scrambled ready prompt. It seems like the computer itself is fine because it is able to process commands even though the output is all scrambled. When I typed "print mem", it responded with 3583, so Im guessing that the ram is fine. I have attached screenshots that will better explain my issue. Any advice is appreciated.
 

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TRS-Ian

Veteran Member
Joined
Sep 10, 2011
Messages
1,036
Location
Melbourne, Australia
Is this a Level 1 or a Level II computer? Did it previously have a lowercase modification made? I ask because if you remove the lowercase mod and don't restore the trace cut then you get a screen like this...

Maybe post a photo of the motherboard in the area around Z29.

Cheers,

Ian.
 

tdog557

New Member
Joined
Aug 11, 2014
Messages
4
Thanks for the reply, it is a level 1 computer without any modifications made. Im not very familiar with this computer, so I havnt gotten a chance to take it apart yet, is the anything I need to know about taking it apart?
 

tdog557

New Member
Joined
Aug 11, 2014
Messages
4
Thanks for the advice, I was careful with the cable. I have attached some pictures of the board around Z29 if it helps. Just to be safe, I also reseated the chip at Z29 but the issue is still there.
 

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Last edited:

tdog557

New Member
Joined
Aug 11, 2014
Messages
4
Hello everyone, I recently took another look at the board and found what appears to be mold on the chip at Z11. Could this chip be causing the issue, or could the problem be with another chip? Ill post a picture of Z11 to better describe it.

DSCN1121.jpg
 
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