Kistler 5134 with corrupted PROM, Firmware Request (FW1.1)

[2nOrderEDO]

Hello there,

A friend of mine was repairing a Kistler 5134 and found out the problem to be a corrupted PROM firmware. He replaced the memory IC with an EEPROM and programmed a more updated version of the firmware (V1.3) from another of these amplifiers we have around, but it seems to be working only partially. There are some menus in which the screen goes black and the instrument locks (we believe it hits an infinite loop in the new firmware).

My friend contacted Kistler to ask for the original firmware file (V1.1), but they said this model is too old and they do not know where it could be. None of the units we have here have this firmware version.

So we want to make a general call here on the forum to see if someone knows where to get this firmware, or if someone has this unit an can read and send the ROM. That would be very much appreciated. I attached a picture of the original PROM IC.

We thank any helping hand :-)

[fenugrec]

Can't help you, but could suggest alternate routes, depending on how bad you want the original firmware :

With a "proper" EEPROM reader, experiment with different supply voltages and readout speeds. Hopefully you can retrieve some, or maybe all data.
Scope data pins to find if there are weak drivers (and could use an extra pull-up/down resistor ), stuck bits,  and so on. Save every dump attempt just in case.
Compare whatever you do manage to dump with the 1.3 image, piece by piece - you may be lucky and find that many sections are identical or very similar. You will need at least a disassembler for this (which CPU ?), or ghidra if you have time for the learning curve.