Fluke 335a

[RoadDog]

So I finally received my 335a. It was a long wait as it got stuck in shipping for a few days.

After letting it warm up for a while and then running through some settings on different ranges it seems to need to be centered. On all 0’s my meter is reading negative voltages and doesn’t read close to 0 volts until setting 0000084 on the ten volt range. On the 1000 range I can increase until 125 volts and a relay kicks at 126 and output drops to nothing.

The 34401 is new to me and no clue about calibration but it agrees closely with my Fluke 45 which was calibrated last spring so I figure it's close.

The calibration seals are still intact on the top cover. No clue what the inside looks like. I’ve read most of the posts here about these so understand I may be in for some work.

Fun piece of equipment though and look forward to digging into it. I’ll post progress pictures and videos as I go along.

[Swainster]

Did you put the "trip" switch to the 1000 position when you tried to go above 125V?

[RoadDog]

Did you put the "trip" switch to the 1000 position when you tried to go above 125V?

No I did not. Suppose I should RTFM

I was so excited if finally arrived and started playing around with it. It's pulled apart at the moment. Haven't dug into it yet. Been busy with work and getting ready for the holiday.

[RoadDog]

Well the Fluke 335 is a drifty old girl. Have to adjust it up in the different ranges to be at/near 0 volts.

I know the electrolytics and tantalum’s are notorious for getting old among other issues. Initially it drifts around quite a bit. After an hour or two it settles down to drifting +/- 10 uV or so. On the 10 volt range its putting out about zero volts with the settings at about 700 uV. If I set all the knobs to zero it’s putting out a negative voltage and it differs on the 10, 100 and 1000 volt ranges.

Still haven’t cracked it open. Pullled the top plate off and pulled it a bit out of the case but didn’t go farther.  Just been playing around and comparing different meters and going through the ranges on the 335. Spent a good portion of this afternoon just watching it drift around and seeing how it acts. None of my equipment is calibrated. The 34401 is new to me and while it seems solid I’ll  send it out to be calibrated some time soon.

The 845 seems to be good. It’s less finicky and settles quicker than the one I used in a standards lab I worked in for a while. It’s an interesting piece though. It’s similar to an 845AB but this one is only labeled as an 845A and doesn’t have batteries or the extra switch settings that the AB has. I’ve never seen one like it in person or online. Looks to be the newer, updated circuits and not the old neon chopper.

Grabbed a manual for the 335 and will bust it open soon and see what I’ve gotten myself into. No clue how I’ll get this thing calibrated down the road once I get it working better but I suppose I’ll figure it out when I get to that point.