[winchdoc]

Greetings all-

I've been a part time lurker for some time here, and I'm looking for some Diagnostic ideas.

I have a 5VC750 with the Acramatic control. It has lived in my garage for the last 20 years as a hobby CNC mill. It has been pretty reliable all this time especially considering it's 1984 vintage.
I have kept it going, repairing a drive board, changing out a spindle drive, etc.

Here's the new problem-

Power failure caused memory loss. it's happened before. Simple remedy load all the exec tapes.

When attempting to load 1st tape I get "load error 1" (data transmission error)
I ran the tape reader diagnostic for the acraread LS tape reader. It PASSED
I was able to swap a different (working) tape reader and still get "load error 1"
Of particular note, the DGN led on the MMU board lights when the "load error 1" happens.

so, I'm pretty sure the problem is further downstream of the tape reader.

I performed all the CIP-based firmware diagnostics outlined in the TAG book, everything PASSED.
Including the MMU test.

My question, Where do I look next?


Doug Boyd

[machinehop5]

...Wild Guess. not sure about how the 900 Acramatic memory was stored back than but, there maybe a Dallas Chip somewhere on one of the PCB that has failed. I've seen dead batterys cause a Voltage drop/pulldown enough to not allow memory to operate correctly.
https://www.classic-computers.org.nz...ttery-chip.htm