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I could find no schematic nor data sheet online for what appear to be DC power supplies. There are two terminals on the smaller ones small cardlabeled output +, -, three pins labeled input 1, 2, 3 and a lone pin labeled INH. The larger boards enter image description here are nearly identical except the have an additional smaller transistor and two additional +, - output pins bridged two the first two. large card outputs Please help me identify these. I have a three boards of each type that came with a four 24v AC powered CCTV cameras.24vAC cam panelcamera side view Is a 3 phase voltage requirement possible? Would it be a bad idea to apply 120VAC to two pins? I would be willing to take the risk but don't want to fry any of them unnecessarily. They are labeled: "POWERTEC INC. - Chatsworth CA", for which searches returned no electronics manufacturer. Then below: "WARNING: THIS UNIT MUST BE PROPERLY CONNECTED TO AVOID DAMAGE. PLEASE REFER TO DATA SHEET", no data sheets were included nor found online.

Note that the cameras are 24v AC. The cameras are NOT what I am interested in, I have use for DC power supplies. They are not labeled for voltage. On the big cards the large wired pot is labeled 'E out ADJ' (output voltage?), the twin pots are labeled 'OVP ADJ' and 'I lim ADJ' (What is OVP? Is input variable?). It's larger transistor is an RCA 2N3055 CVV 3F. The small transistor is labeled RCA 13159 2 CHG 3J. It's large cap is labeled 'STM 32-13007-001 39CS15JL93 9000 MFD 15VDC 11C07315 85(deg)C'.

The small cards pots are identical. It's transistor is 'RCA 13002 3 CVFJ 3C'. It's cap is labeled 'STM 39C30HH182 32-13007-009 1800MFD 30VDC 11607221 85(deg)C'.

What is the 'INH' pin?

Thanks for insight!

Jean-Paul McCoy
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  • Welcome to EE stack exchange. Can you try to take a better picture of the top side of one of the boards? It might help people figure out what is what. The current picture is blury. – user57037 Mar 14 '18 at 07:34
  • It looks to be a non-isolated line powered HV DC supply. But its too hard to tell which pins are line and neutral. – Tony Stewart EE75 Mar 14 '18 at 07:35
  • It would be much easier to identify power requirements for the CCTV cameras and get modern power supply than to deal with these hand-crafted DIY-style old stuff. And can't you have your phone camera not to shake that much? – Ale..chenski Mar 14 '18 at 07:35
  • looks like late 70's technology, high risks of failure from wrong connections but looks like they used AC ground for DC ground. – Tony Stewart EE75 Mar 14 '18 at 07:45
  • it Looks like a DC regulator, possibly a battery charger for connection to a transformer. one of the three input pins may be for a ground connection., a clearer photo would be nice. can you stabilize your camera somehow? – Jasen Слава Україні Mar 14 '18 at 07:53
  • what is written on the large capacitors? and the TO3 transistors? – Jasen Слава Україні Mar 14 '18 at 07:54
  • probably 500V 1mF and large linear regulator parts with trimpots – Tony Stewart EE75 Mar 14 '18 at 07:57
  • I suspect that the input pins are for connection to a 12-0-12 V transformer, but we'd need to see the traces on the other side of the PCB. Are is the video equipment actually related to the power supplies, or did they just happen to come in the same cardboard box? – Andrew Morton Mar 14 '18 at 10:24
  • The post is a bit older - but maybe .... You can find 4 of these PSU - boards e.g. in the Moog Modular 35 or 55 synthesizers. 930A power supply for several voltages. The Service Manual for Modular Moogs shows the schematics, setup and and in and out connections. cheers – Wal Nov 07 '22 at 12:58

1 Answers1

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E out ADJ - voltage output adjustment [think EMF].
OVP ADJ - (output) over-voltage protection adjustment.
I lim ADJ - (output) current limit adjustment.

The 13002 transistor is equivalent to an NTE130 which is equivalent to a 2N3055. A search for "2n3055 power supply circuit" gives lots of results.

At a guess, INH could be "inhibit," as in switch off the output. But from its location, it could be some signal that the PSU is getting input power (input high?).

Another guess, in view of the 30 V-rated capacitor, is that the three input pins are for connection to a 12-0-12 V transformer (i.e. centre-tapped), or maybe 6-0-6 V.

I suspect, unless you know otherwise, that the video equipment is not related to the power supplies.

It would be a very bad idea to apply 120 V AC to the input.

Andrew Morton
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