Tandy TRS-80 Model II Issues

[dkarguth]

I am trying to restore a TRS-80 model II and have run into this problem.


(sorry about the garbage picture, the phone camera wouldn't cooperate with the CRT refresh rate)


When I power the system on, it displays this flickering screen with the message "Boot Error MF". I know that this means it has a memory fault, but I have tested all the RAM in the RAM card, and replaced the single faulty RAM chip with one from the other card. (it was a 32k system with another 32k card installed.)
I realize that the boot error could be due to an addressing problem, but the flickering is what has got me stumped.

So far I have done the following to the machine:
-Recapped the PSU, CRT driver board, backplane, and all the logic cards.
-Cleaned the card edges and connectors on all the cards and backplane
-Tested all the RAM chips, and replaced faulty chip
-Reseated all the DIP ICs
-Removed all the cards apart from the CPU, Video card and Memory card, and still get the error. (the error is the same when the memory card is removed)
-Rearranged the cards in the backplane

Nothing so far has helped at all with the issue, so at this point I'm stumped.
I'm new to TRS-80 systems, so I have very little knowledge of their common problems or failures. This machine is a particularly important one due to the low serial number, and I would like to see it restored and working.
Any help anyone can give is appreciated.

 

[pski]

Welcome to the Model II, the system collected by the masochists of the TRS-80 world!

I would next check your power supply voltages at the card cage. You might have a weak 5v. The M2 Technical Reference Manual has the pin out for the 80 pin connectors. Also, you mentioned rearranging the cards, but the cards need to be in a certain order. The ref manual and Notes and Jumpers has the details.

 

[memotronics]

I am trying to restore a TRS-80 model II and have run into this problem.

View attachment 1065407
(sorry about the garbage picture, the phone camera wouldn't cooperate with the CRT refresh rate)


When I power the system on, it displays this flickering screen with the message "Boot Error MF". I know that this means it has a memory fault, but I have tested all the RAM in the RAM card, and replaced the single faulty RAM chip with one from the other card. (it was a 32k system with another 32k card installed.)
I realize that the boot error could be due to an addressing problem, but the flickering is what has got me stumped.

So far I have done the following to the machine:
-Recapped the PSU, CRT driver board, backplane, and all the logic cards.
-Cleaned the card edges and connectors on all the cards and backplane
-Tested all the RAM chips, and replaced faulty chip
-Reseated all the DIP ICs
-Removed all the cards apart from the CPU, Video card and Memory card, and still get the error. (the error is the same when the memory card is removed)
-Rearranged the cards in the backplane

Nothing so far has helped at all with the issue, so at this point I'm stumped.
I'm new to TRS-80 systems, so I have very little knowledge of their common problems or failures. This machine is a particularly important one due to the low serial number, and I would like to see it restored and working.
Any help anyone can give is appreciated.

I'm getting EXACTLY the same thing, with the same garbage on the screen and BOOT ERROR MF

Did you ever get yours working, and how ?