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TRS-80 Model 3 - mice damage, CPU and ROMs removed

Hmm, that's bad luck then. It's going to take ages to fix all those keys.
 
Remember, that your DiagROM has a Jumper that when placed in the Other position
is a Keyboard test of the ROW Column Matrix. You will need to depress a Key
as the program is running and it should show the transition from 1 to zero as
you depress each key.

You should be able to test the address lines as they are toggled and shorted to
the Data Lines for the Row/Column Matrix.

Larry
 

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Robbbert said:
Hmm, that's bad luck then. It's going to take ages to fix all those keys.
Click to expand...
yep. Model II keyboard rebuilds are a tedious and torturous act of frustration.. But you get there in the end.. Its not hard. I have been putting one off for a long time.
 
Larry, I tried the diagnostic ROM for the keyboard test and pressing any key doesn't do anything--nothing changes on the screen. I tried shorting as well, and still nothing. But the diagnostic ROM behaves erratically, in that when testing the RAM or keyboard, it displays the large (32 column) characters, and every *other* column/character is displayed. Every once in a while it displays fine as 64 columns. I just did the RAM test a few minutes ago and it displayed in 64 columns. But twice tonight I tested for the keyboard and it still displays 32 columns--every other column/character. I tried shorting letters G F E D C and none of the zeros changed to a 1.

Note, the attached image for the keyboard test shows the 32 column issue, it's just luck/chance that every other column removed the space in between each letter, but in the 0/1 columns, only 4 (not 8) columns are displayed. Knowing this, I tried to test every letter in the first row (G, F, E, D, etc.) and another row, but none of the zeros ever changed to a 1. Also, not sure why some 1's appear--it's always like that. I assume all should be zero, until a key is pressed.

Note #2. As you can see I'm using an IBM monitor (5153). The monitor's input specs don't match exactly what the M3 video is giving (and there isn't a horizontal size/hold knob), so the first column is out of view on the left.
 

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...forgot to mention, when I use ROM A (not the diagnostic ROM), it shows the Cass? prompt in 64 columns just fine. Not sure why the diagnostic ROM is erratic.
 
I'm traveling headed for Sun City, AZ. When I arrive I'll look into what sets 32 Char vs 64 Char.
It should come up in 64 Character Mode.

Larry
 
Hello all. On my TRS-80 Model 3, I'm looking to replace the black and white wires that come from the power cord and connect to the PSU(s). But I'm having trouble finding the 3-contact (only 2 are used) connectors that connect to the male (two post) connector on the PSU. Since I have two PSU's the first connector 'vampires' off of the hot and neutral wires, then about a 12 inches further, the hot and neutral wires are terminated at the second connector. Has anyone ordered these, if so, where and what is the technical description or manufacturer/part number?

Also, I can't find an 8-pin FFP/flat-flexible cable long enough to replace the old one. It's the cable that connects right above the CPU to a connector at the top of the motherboard. I found one on DigiKey but it's only 8 inches long, and the original is 8.5 inches. The only ones longer are only sold in bulk. Has anyone replaced this cable and where did you purchase it? Thanks.
 
 

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