EEVblog #791 - Ebay Fluke 45 Multimeter Teardown

[EEVblog]

Dave scored a Fluke 45 on ebay, the world's first dual display multimeter
Does it work?
What's inside?

Service Manual: http://oldradio.tesla.hu/rajzok/muszerek/fluke45.pdf
HD6303 Processor: http://www.cryptomuseum.com/crypto/philips/px1000/files/hd6303rp.pdf

[Moshly]

+1  for the Austen Tayshus (random interlude)

I was just watching that the other week on YT ->

https://www.youtube.com/watch?v=StcXGhuliRk&feature=youtu.be

[Huluvu]

nice Score 

I received mine in a almost new and unused condition which is very impressive considering that this unit was probably build around 2003/4

[retrolefty]

I've had mine for decades now. I've used the RS-232 output, it's simple to interface/convert for just about anything.

Too bad the volt-nuts will pass on the voltage reference used. 

Looks like it might have had a long production run, anyone know the facts. I do seem to recall a $799 retail price.

[Fungus]

Still $100 for a slightly beat-up, "as-is" meter after all those years? Jeez.

(And that's at "Dave" price. Everybody else will have to pay $200.)

[dentaku]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

[Muttley Snickers]

I honestly took it for granted and automatically assumed that he would have acquired a few of these over the years and always had the impression that he didn't think much of them or that they were simply to old. The average price is generally around $200 to $300 and sometimes a lot more, this is why I haven't given them a second look but also most listings either show a dim VFD or the unit powered down and I did keep an eye out for a good one for many years but gave up trying, that may change after seeing this video.

Thanks Dave for a fantastic insight....

Muttley

[Macbeth]

Clearly in need of a new VFD. Unobtanium is my guess?

[Tek_TDS220]

At 31:15 the copyright is 1986, not 1996.    Any chance the display is dim because the high voltage supply has sagged a bit? 

I would have liked a bit of explanation about the AC input buffer.  It looked more complicated than I expected.

I always learn a few things from these videos - thanks!

[Fraser]

I own thee. 8842a bench multimeters. They still have superb accuracy and all are working well. I have not regretted buying them for a second. IIRC I paid around £60 each for my units. I owned the 8842a before buying an 87 III 

The VFD is a weakness in heavily used units. It was still available from FLUKE when I last checked.

FLUKE made some top notch bench meters, the 45 is no different but I have found it to be overpriced on eBay. Personally I would avoid a dim display unit though as it isn't normally the HT, it is the Tube that has degraded. Some people have had success in overdriving the display to 'refresh' it..... Not a reliable process though.

Aurora

[linux-works]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

http://www.retr0bright.com/

[linux-works]

I've had mine for decades now. I've used the RS-232 output, it's simple to interface/convert for just about anything.

Too bad the volt-nuts will pass on the voltage reference used. 

I have 2 of them I bought a few yrs ago when they were below $200 (dirty and took a chance on them but both ended up being just fine).

the voltage ref is not 'volt nut certified' you say?  its not a 6.5digit meter, though; wonder why a fluke design from that (good, old) era is not acceptable to those folks?

the build quality is great; very robust and reliable and not much to go wrong.

if the display starts to fade on me, I'll probably upgrade it with my own display and controller (the rs232 control port on the back is the key and I'll be able to get the data I need and send it to some other device for display or maybe retrofit my own display inside the fluke, should the real vfd not be buyable anymore.

btw, one trick to restore the shine to the plastic display is toothpaste and cotton cloth.  an old tee shirt works great.  use your finger and dab some toothpaste (a fine polishing compound, really) on the display and rub with fingers.  use a cotton cloth (keeping it clean frequently) and use that to polish the plastic lens.  on each bit of gear I've had to do that to, it restored the shine and can remove some surface scratches.  careful over painted areas, but on the smoked bezels, the toothpaste trick is a pretty well known trick.

[steve30]

The Polyputthekettleon capacitors is definitely one of my new favourite quotes .

[Macbeth]

Too bad the volt-nuts will pass on the voltage reference used. 

Oh I don't know, the Solartron 7081 8.5 digit uses a zener diode as its reference. The volt nuts quite like that meter. I think it's a 1N829?

Daves Krohn Hite voltage standard

 

also uses (the same?) plain through hole zener diode reference and that thing is amazingly spot on compared to a cal lab 3458A (and without a Kelvin Varley divider too!)

[boffin]

Dave; is the dim VF display due to a bad cap on that -30v line?

[Wytnucls]

Advert June 1989:

[Luddi]

direct RS232 output is nice.
I build a simple GPIB -> serial -> USB adapter for my HP 3455 with an ATMega, it has a "talk only" mode so i only have to acknowledge each byte, and they are plain text like the Fluke does.
Datalogging with a 30+ year old meter with basicly unlimited length

[D3f1ant]

I still have a Fluke 45, and until a year or two ago it was in daily use. The VFD screen is still bright, and it was still within spec accuracy. A nice feature if your into audio is DBm and audio power measurements.
My users manual was printed Jan 1989, and there is an errata insert dated June 1989. I think I got in about 1992 or there abouts.

[Tothwolf]

The 8V battery pack makes a lot of sense. From the photo, it looks like they are using 4x 2V 2.5Ah sealed lead acid cells, most likely Cyclon D size (p/n 0810-0004) from Enersys/Hawker/Gates. I've replaced tons of these batteries in other 1980s vintage portable instrumentation, and given their popularity, I strongly suspect that's what they used here. [Fun fact: It isn't uncommon to get a 10-15 year service life from a Cyclon SLA cell in a float charge configuration.]

I wouldn't consider the power supply design all that convoluted either. That particular switching converter arrangement makes a lot of sense given the rechargeable battery option.

[Someone]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

http://www.retr0bright.com/

There are many variations on that idea, I found a useful recipe with 6% H202 in hot water with plenty of washing powder containing Tetraacetylethylenediamine. You leave the mixture out in the sun for a few days and plastics come out happy and white. The advantage is the ingredients are cheap so you can create large baths of it.

[XFDDesign]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

http://www.retr0bright.com/

There are many variations on that idea, I found a useful recipe with 6% H202 in hot water with plenty of washing powder containing Tetraacetylethylenediamine. You leave the mixture out in the sun for a few days and plastics come out happy and white. The advantage is the ingredients are cheap so you can create large baths of it.

Is this 6% solution from the store, or 6% of the brew is H2O2? What powder contains... that mentioned compound?

[calin]

i got a Fluke 45 just few months ago with 40$ from craigslist almost new condition, looks and feels like new to me, with manual and all. This video is right in time . Mine has a super nice bright VFD .. heck I can't balem anything on it.


It quickly became my preferred bench meter especially because it does it just right on many things and yep the RS232 is ridiculously simple to read in a file over time. Simple to use, no fuss .. heck I got a pair of nice ProbeMaster leads just for it that were half the rice of the mete.  I alsso have his bigger brother 5 1/2 digit 8442A and both the 45 and 442A are still bang on on par with new 71/2 Keythley's i have at work. Pretty darn impressive from a Zenner i wold say

[teerosheyal]

Dave, Can you do a video on how to find and buy that kind of equipment on Ebay? I never find these deals you are talking about...

[Someone]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

http://www.retr0bright.com/

There are many variations on that idea, I found a useful recipe with 6% H202 in hot water with plenty of washing powder containing Tetraacetylethylenediamine. You leave the mixture out in the sun for a few days and plastics come out happy and white. The advantage is the ingredients are cheap so you can create large baths of it.

Is this 6% solution from the store, or 6% of the brew is H2O2? What powder contains... that mentioned compound?

Aim for 3-6% in solution (the final mix). As for the washing powder you'll need to do some searching for yourself as the brands and products available worldwide vary considerably.

[Tothwolf]

Since it works so well and there's no repair video needed, maybe you could do a video about cleaning yellowed plastic enclosures.

http://www.retr0bright.com/

Unfortunately, this is only a temporary "fix". The yellowing eventually returns, even if the plastic isn't exposed to light.

Retr0Bright (or RetroBright) treated plastics re-yellowing even with minimal light exposure?