Fluke 407D Power Supply

[MartinJM]

I just joined this Forum and noticed a topic posted last year regarding the Fluke 407D Power Supply.

I was interested in purchasing this unit, but could only find very high priced versions from instrument companies. Any suggestions on where to find a decent one when you are on a "hobby" budget?

Thanks in advance.

 

[gootee]

Maybe keep an eye on http://www.govliquidation.com .

- Tom Gootee

http://www.fullnet.com/~tomg/index.html

-

 

[BHBennett]

Howdee. I actually have two of these (I can only locate one at the moment) and I am going to restore it. BUT ... I cannot find a legible manual anywhere. Does anyone have such, or at least a schematic? The one on BAMA is a 407, not the D version, quite different. It is more or less working but I want to do a full restoration. It's one BEAST of a critter. Thanks!

 

[ArcticBrew]

This is whre I got a scematic. Download is free for non-commercial use.

http://www.rainers-elektronikpage.de/Sonstige-SM-und-SM---Infos/FLUKE_407D_Service-Unterlagen.pdf

I have one 407D and 2 407DR. I bought the second 407DR for parts. Of the 2 working supplies neither can hold a steady voltage above 350v with signficant current draw.

I replaced all the tubes, fixed burnt out resistors and other minor repairs but, that was insufficient. Only thing left to do is replace large caps. I since acquired other supplies that are suitable for my testing and have not gotten back to these repairs.

I will be curious to learn about your results.

Steve

 

[ArcticBrew]

http://www.rainers-elektronikpage.de/Sonstige-SM-und-SM---Infos/FLUKE_407D_Service-Unterlagen.pdf

 

[BHBennett]

Thanks Steve. I did manage to find the manual, lost amongst my own piles of all things. I had no idea I ever had it so it probably came with some long forgotten auction box purchase. At any rate I'll post my results... waiting on the caps right now, expect them monday. I usually post on the ARF forum, not here, so hopefully I'll remember to update both.

 

[Tubelab_com]

Of the 2 working supplies neither can hold a steady voltage above 350v with signficant current draw.

I can get about 450 mA out of mine at any voltage up to 550 volts (the fine dial doesn't work) before it goes bonkers. If I stick a 100 uF motor run cap across it's output it can feed a big tube amp that sucks about 600 mA on peaks and 350 mA average without hiccup. Mine still has all the original parts in it including the 807's and bumble bee caps. I got it on Ebay maybe 10 years ago for $25 plus $45 shipping. It was from a surplus dealer / metal scrapper in "untested" condition. The meter switch was loose and had been twisted around until one of the wafers broke. A little JB weld fixed that.

 

[BHBennett]

I'm going to guess that if you replace the bumblebees, you'll find it working a lot better. Also, there is no reason at all that the electrolytics should still be any good lol. My caps just got here today so stay tuned .. I'll be working on it this weekend.

 

[Tubelab_com]

Right now I'm of the mindset that if it works, why mess with it. It's been abused quite a bit since I got it 10+ years ago and I haven't had the cover off since I got it. It will go into some kind of motorboating condition when asked to supply far more current than it's rated for. A big fat cap across the output fixes this. Sooner or later I may need to rebuild it, or maybe I'll have something better before I need to crack it open.

I also have a Knight KG-664 for lower voltage and current experiments. I got it for $25 at a hamfest at least 20 years ago. It worked fine until I left it in unheated storage during a winter where we saw temps in the -10 to -15 F range. Upon reawakening, it promptly spewed electrolytic goo all over it's insides. Autopsy revealed 4 RCA black plate 6L6GC's inside, so they got swapped for Chinese tubes. All the electrolytics and a few other parts that didn't look so well got replaced, and it soldiers on.

I also have a HP 6448B which is an old style 60 Hz switcher (slow to react) with 1000 uF internally across its output. It is capable of 650 volts at 1.7 amps. With that power plus the stored energy available in the output caps experiments can turn to shrapnel real quick.

I am currently working on a Sorensen DCS 600-1.7 (modern SMPS) which when finished should be capable of reducing the need for blast shields over my test boards!