Fluke 97 Scopemeter reset error

[kamocat]

Hi all,
I have a Fluke 97 which has been working happily for many years, but just last week it decided it to act up.
It starts out measuring fine, and then after a few seconds it beeps and warns "** Error *** Please reset the instrument ***"
And then the screen blanks out and flashes the error message with a beep every second.

I have tried a system reset by powering off, holding the LCD button, and powering on. This doesn't seem to have any effect on the issue, although I do believe it does reset because my timescale, trigger, and volt scale are set back to default.

Does anyone have an idea of what might be the issue? The service manual is very detailed but I don't really have another scope to troubleshoot with.
(I found the service manual in the Old Fluke Phillips 97 / 96B thread)

[m k]

Are all modes equally bad?

[KRISTOFFER]

It is a pig of a job but you need to do some continuity checks on the double sided PCB of the top board. Back in the days when these instruments were fitted with ni-cads, the boards would slowly corrode from the battery gasses. I have done a few where everything is fine until you perorm certain functions then they either power off or do stange things. In a nutshell the tracks can supply enough current to get the things up and running, but any voltage drops, when say the processors need more current, and it all goes wrong. You will notice if you get the chance to open a good few of them up, that there are wire jumpers added all over the boards that were not from oringinal production.