Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Hello Kiriakos,
You're right, it doesn't make much sense. So, I thought I would find the temperature sensitive part. I heated up a metal rod and went around touching stuff. Some little changes but what I would expect. You suggested cleaning the board. Yeah, right, I thought. That's going to make a difference. The board looks really clean.
Anyway, I grabbed the isopropyl, a brush and some paper towels and started cleaning the underside of the board. Immediately, I smelled the stink of old cigarettes. I hadn't noticed...

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Well, I had a chance to look more into this and I found that the 20V range is VERY temp sensitive. Even blowing on the circuit board will change the offset from -30mV to -100 or even more. I am really confused by this.
What is different with the 20V range? I will try to add more as I try to investigate further...

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

The resistor divider network is OK. I have gone over that very carefully. I have even measured higher voltages and accounting for the offset they are accurate.
Your idea about the switches is a good one. I will definitely check that! (I will be busy with other things for the next couple of days and will not be able to do very soon. :-( )
I really like keeping this old equipment alive. I am determined to find what is the problem here.
Thanks for your help and interest!

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Hello Kiriakos,
Thanks for the reply. I think you mean C8 and C33. I thought about these, too, since in the documentation it says they store offset voltages to the integrator and comparator. The thing is, the A/D circuitry obviously works because the 200mV and 2V ranges are fine. But, if I can't find anything else I may have to swap these out and see if anything changes.
Thanks again!

Re: FLUKE 8050A searching adjusting tip to set DC at 0000

Hello all,
I found this thread (and site) because a search led me here. The problem here is not exactly what I have but kinda close. Maybe someone can help lead me to a solution. Thanks!
I also have a Fluke 8050A-01 and it works fine except that the 20V and higher ranges have a negative voltage offset. I got this off eBay and expected to have to put new batteries in. I swapped out the dead Panasonic NiCDs (already a replacement) and used NiMH units. (I know that constant trickle charging can kill NiMH so I simply...

Re: New Members - please post your introductions here

Hi all,
I'm Totoro and found the site via a search that referenced a thread. Looks like a great place. I play with Arduinos and audio. I also like old test equipment and keeping that stuff running. My job background is in programming but I've been keen on hardware since I was a kid. I am always learning and hopefully I can share my (limited) knowledge here. Thanks for the opportunity to do both.