Looking for power supply manual(s)

Hi all.

Last weekend, I picked up from my favorite electronics junkyard one of these power supplies - an ECI 20500B:


Made by this company:


The picture in the auction above is virtually identical to my supply (except mine is missing the outer casing); I have verified that it seems to work properly; I had to fix a few minor issues (new binding posts, a new power switch, etc) - but it appears to work OK and no magic smoke was let out!


I am pretty sure it is an “obsolete” product; I contacted the company about it, looking for manuals (specifically the user and the service manuals), but I have yet to hear anything from them. I am mainly wanting to have this information for any future service needs, as well as to know the proper specs of the device, and to make any adjustments (there are a few trim pots on the PCBs inside, but I don’t know what controls what, and I am not going to fiddle with them until I do).

By my best guess, it has a limit of 1.5 amps MAX; at least, that’s what the inline slow-blow fuse after the main transformer (there are two; one goes to the switch and the DC convertors, the other is connected to this fuse and hook up to two legs from an AC transformer via a couple of resetable panel breakers).

There’s a fixed 5VDC output, plus a variable 0-25VDC output with setable current limits and current monitoring via the digital 7-seg LED display.

While these are the specs I know, I have found that I can’t crank the current up all the way to 1.5 amps; it will only go up to about 1.45 amps; plus it will only go up to about 24.6 or so volts on the adjustable supply. The AC output seems larger than what the front panel says its rated for (by a few volts). IIRC, the 5VDC fixed output is fairly spot-on, but I might need to re-check that.

If anyone here has a copy of these manuals, I am willing to pay a reasonable price for them or for copies.

Thank you for taking time to read this…


Oooo, nice catch.

With a 1.5A fuse, I’d guess that it’s actually rated at 1A or so: even with a slo-blo, you don’t want to be operating equipment at/near the fuse rating continuously.

With a 1.5A fuse, I’d guess that it’s actually rated at 1A or so

Well, that’s making the assumption that the fuse was never changed, and when it was it was changed with the same type fuse. These power supplies seemed to be a part of an educational lab; they are all (the place I bought it from had several; I chose the one most likely to work) in ugly shape (and I have to guess that the users of them were either tarded or careless; many have burns and melted areas from soldering irons - in places where the iron shouldn’t have been near, and you can almost see it was done deliberately).

I would really like a manual with the detail needed to know what is set right, what isn’t, what the fuse rating should be; in short everything I need to know about the power supply. If 1.5 A is meant to be the “top end”, that could explain why you can’t set it to go that high with the controls (you can only get “close”). Still, a service manual would be helpful, especially if it needs to be calibrated in some manner.

I am probably going to contact ECI directly, since they didn’t seem to care about my email…

Had such good luck last time, I went back and picked up a second; this one has a similar switch problem that I will have to fix (but I found some nice switches, too).

I am still looking for manuals; no reply from ECI to my queries (I will probably telephone them next week).

I also managed to find some L298s (got 5 for $1.50 each), and some TO-220 case 3055 MOSFETs for 75 cents each (10 or so)… I love Apache Reclamation here in Phoenix; you never know what will turn up (interesting find this week: a defibrillator machine that wasn’t too old - didn’t buy it, but it wasn’t there last week!).


I sent another email to ECI earlier this week, but got no response, so I called their toll-free number this morning and spoke with a gentleman there; he said he was going to mail me both manuals for the power supplies.

He also told me that the original cost for those supplies was $595.00 (US) each! I guess I got a pretty good bargain @ $25.00 each!


Today I received the manuals! ECI is -amazing-! It isn’t often that you find a company willing to supply -real- manuals to their obsolete/discontinued products. I managed to get both the user manual and the maintenance manual (with full schematics). Read my “thank you” article about this at my website:


Once again - a big THANK YOU to Energy Concepts, Inc!

:slight_smile: :slight_smile: :slight_smile: