Fluke 845AB Needle Porn

[@largepimping]

Stepbro, your needle is perfectly centred on zero.

[@tgsoapbox]

LOL

[@tarheels100]

Best thumbnail ever.

[@tgsoapbox]

Got to love the KZbin AI - Updated....

[@tarheels100]

@@tgsoapbox They nailed it! 😂

[@DrFrank-xj9bc]

quite noisy. looking forward to repair of chopper Neons.

[@tgsoapbox]

Thanks, Dr. Frank - I see over on EEVBlog that people have used Barthelme 82305 neons as direct replacements (I'd like to try and keep the unit as original as possible) but I can't seem to find any - Suggestions on a source or other replacement?

[@zdzisiek1979]

🙂👍

[@harrybond007]

What exactly is the problem?, no commentary no nothing?

[@tgsoapbox]

This was just a video showing the needle bouncing around due to the noise in the photo-chopper circuit - Really just a celebration of the D’Arsonval movement

[@harrybond007]

@@tgsoapbox OK, I was watching your video because I recently picked up a Fluke 845AB at a hamfest for next to nothing, it appears to work to some extent but it's not very accurate and the meter is very erratic. I guess this is a common problem, I'm not sure I even know where to start attempting to repair it. It's dated May 1969, mechanically it's in good shape.

[@tgsoapbox]

@@harrybond007 Dr Frank pointed out that he posted to this thread over on eevblog - www.eevblog.com/forum/metrology/teardown-fluke-845aabar-tweaks-and-mods-(and-repairs)/?all - about the neons and capacitor replacements that addressed the noise in his 845AB. I did a Neon update and showed that in a later video but I haven't yet looked at the caps in the unit. It'd be worth checking out that thread for insights into what might be going on with your meter.

[@harrybond007]

@@tgsoapbox thanks for the link, that is a great resource, I did search online but never found that, are these units still useful?, still used today?, the used ones on eBay are listed at high prices, even if not tested?

[@tgsoapbox]

@@harrybond007 Sort of, really depends on what you're doing. If you have an 8.5 digit meter then in most cases you can just move on from these - Though in one of the threads on EEVBlog they have a discussion about current bias and how these null meters are still better than the current 8.5 digit ones for metrology purposes. I had a chance to acquire one for a fairly inexpensive price along with a Kelvin-Varley divider so I thought I'd just go do it and see what goes - I am a noob when it comes to these units as well. Good luck.

[@xufocom]

+/- 1 uV - its normal (in specs)

[@tgsoapbox]

Thanks, I do think it is out of spec as that wobble is on the 10uV setting in zero and operation (with nothing plugged in).