FLUKE 5100A Display issue

[Crambone]

I have a 5100A that when powered on nothing lites up on the front display but when you power off it blinks for a split second. I can’t find any info as far as service manual, schematic….
I’m wondering if the 5100a and 5100b share any similarities?
I would like to find some voltage specs especially for the power rails….
If anyone has any inside or info (document) to share it would be greatly appreciated.

Drew

[bdunham7]

They're very similar and AFAIK the modules interchange, but IDK what specific differences there are.  IIRC user Runco990 had one of these with a similar problem and the issue was that there is a 555-based oscillator on the PSU board that drives the display multiplexer and his had stopped oscillating.  Just use the 5100B service manual until you manage to locate the 5100A version.

[Runco990]

Yep, my 5100 damn near killed me trying to figure THAT one out.  Check the 555 on the bottom right corner of the power supply board first.  It is the clock for the display.  I soldered a wire to the output so I could get a probe on it without an extender.  Of course, check all fuses and voltages on the Power supply board before digging in deeper.  As far as I know, most of the 5100A and B are interchangeable.  I have swapped most boards and all work.