Fluke 8000a fault

[KD9CJX]

Good afternoon and thanks for reading. Did some searching for this fault and didn't see a thread so I'm going to start a new one. I apologize in advance if it's been answered.

I have a Fluke 8000a with battery option. On startup, I got a flashing "1999" on the display. Decimal point moves when range is changed, but no difference in the display. So I broke out the manual and followed the troubleshooting procedures. When shorting out S4 to TP4, I finally got a change on the display. It jumped around and was erratic, but it was something different. So I changed out the analog IC and related resistors/caps/diodes with a NOS analog IC kit from fleabay. After replacing all components, the 1999 was still flashing on the display.

Discouraged, I let it run for a while while I consulted the manual, eevblog, and groups.io for any answers and didn't get anywhere. When I monitor the period output for 10 mS, it's all over the place. So is there some PLL that is wonky? Could I inject a 10 ms pulse somewhere to see if that brings it around?

This is just a "kicks and giggles" project. Probably already spent too much, but I'm just doing it for fun. I have plenty of bench and handhelds but I'd like to get this one running for the collection.

thanks!

Joe
KD9CJX

[NoisyBoy]

Before doing any more testing, check the batteries, they act as the smoothing cap, the meter will not function properly if they are dead even if you run it from main.

If they are dead, put in a set of good batteries before troubleshooting. Good luck.

[Kleinstein]

From the manual, the Fluke 8000 uses voltage to frequency conversion and a kind of auto zero look. So it is normal that the period / frequency is jumping between two values - that is part of the normal operation. The manual has quite some hints on trouble shooting.

[J-R]

Also, be sure to clean the switches...

[med6753]

Is it stuck in Ohms function? 

[NoisyBoy]

X2

Also, be sure to clean the switches...