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THE AM BULLETIN BOARD => QSO => Topic started by: KC4VWU on September 10, 2017, 06:33:10 AM



Title: Tiny Monster P/Supply
Post by: KC4VWU on September 10, 2017, 06:33:10 AM
One of a few acquisitions from the Shelby hamfest. Another gigantic enclosure to add to the overflow of BA test equipment on the work desk. Would have been nice if they had added another section for adjustable heater voltage, definitely has the room for it! Just couldn't resist, 500VDC and 150mA. Guess I do have the option to add my own "A" and "C" sections.


Title: Re: Tiny Monster P/Supply
Post by: WBear2GCR on September 10, 2017, 08:47:37 PM

Looks like a simple lab supply, maybe never made as a commercial product, and just for in-house use?
The caps do not look that old, maybe they have been changed?? Or the entire guts replaced in an older
enclosure??


Title: Re: Tiny Monster P/Supply
Post by: KC4VWU on September 11, 2017, 01:14:41 AM
I've seen a couple others on the online auction site, so it was sort of mass produced. Just really surprised by the size of the cabinet compared to the circuit. Too much BA sized test equipment on the (small) workbench now, this will just add to it. Maybe I'll use it for the time being until I can commit to building my own. It would be nice to have an adjustable filament supply and decent bias supply all in the same enclosure. Had my mind on doing some tube testing/gettering with it. I've had my lesson on rotating in pulls to working equipment at a hefty price to pay; no fun!


Title: Re: Tiny Monster P/Supply
Post by: PA2HGJ on September 12, 2017, 10:36:27 AM
I've got a similar power supply, it came from a local hospital. This kind of supplies where usually used for electrophoresis purposes in laboratories. That's why there is only HV and no filament supply.

Regards, PA2HGJ


Title: Re: Tiny Monster P/Supply
Post by: W3RSW on September 12, 2017, 02:41:10 PM
I surmise He just changed out the caps from old USA made 20 uf Aerovox's to the new 47 uf ones.  ;D
Old cap and handful of terminal strips lurk nearby, not to mention the four now vacant mounting holes spaced just about the length of the old caps just below the rectifier socket.


Title: Re: Tiny Monster P/Supply
Post by: KC4VWU on September 12, 2017, 09:33:54 PM
Yes, I forgot to mention that I had replaced the filter cap, only one 20mf @ 600VDC. It was mounted in the same place with one of those nylon p-clips. I don't try to re-form electrolytics, just replace them. Hope the Chinese replacements will live a while!

There is a IP-17 around here somewhere that I need to get started on, but the price was so right on this supply that I couldn't resist bringing it home.  I think I may add a fixed 6.3v filament and adjustable bias supply using some back to back L.V. transformers and adding a digital readout for that.


Title: Re: Tiny Monster P/Supply
Post by: Opcom on October 26, 2017, 11:51:14 PM
Did a search for electrophoresis power supplies and sort of jotted down the general characteristics of a few compared to the regular old tube type regulated lab supplies.

These have precision and stable setting of voltage and current modes, some up to 4000V and some up to 2A depending on model.

The DC power output is usually no more than 250-400W. They are not plate supplies for that big amp.

They seem as 'good' for hobby uses as the increasingly rare and costly 60 year old rackmounted tube monster.

The biggest difference seems to be that the DC wattage limit on electrophoresis supplies is often less than the product of the maximum voltage and current ratings.

pros and cons of some electrophoresis HV power supplies when used for the electronics hobby:
  • Digital voltmeters
  • Precision of 1V setting or 0.1mA setting.
  • Remote control RS232 or whatever.
  • automatic electronic protection against shorts or overloads
  • More plastic, less iron and glass. Lighter weight.
  • Flyback or other switching regulator.
  • Output timers (up to 6 hours) which may have to be be bypassed
  • GFI-like detector, any leakage to GND cuts off DC. "feature" needs bypassed.

It is usually simple to find the wattage by a googl search for specifications, and see if a unit is useful for one's needs.

Below were found on a casual ebay search. There must be hundreds of them for sale.
Non-working/untested range from $20-$100 and working from about $60 up to $500+ for working or calibrated digitally controlled units.

examples:
  • Beckman Duostat 320800: 0-500V, 0-50mA
  • Beckman R-120: 0 to 500 vdc, 0 to 100 ma
  • BIO-RAD MODEL 200/2.0: 0-200VDC 0-2A, 200W.
  • Bio-Rad 1000/500: 0-1000V, 0-500mA, 250W.
  • BIO-RAD POWER PAC 3000: 0-3000V, 0-400mA, 400W. ($50 broken)
  • BIO-RAD POWER PAC 3000: 0-3000V, 0-400mA, 400W. ($450 guaranteed)
  • E-C APPARATUS EC452: 0-500V, 0-500mA. (looks same as Fisher)
  • FISHER BIOTECH FB-452: 0-500V, 0-500mA.
  • FISHER BIOTECH FB-420: 0-250V, 0-250mA.
  • Fisher Biotech FB 600: 0-4000V, 0-200mA, 200W.
  • LKB Bromma Model 2197: 0-2500V, 0-250mA, 100W.
  • Pharmacia LKB EPS 500/400: 0-500V 0-400mA 200W.
  • Pharmacia ECPS 3000-150: 0-3000V, 0-150mA, 150W.
  • Stratagene Feathervolt 2000: 0-2000V, 100mA, 100W.
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