[MRCA] FW: R-45/ARR-7 Power Supply?

Sun May 28 11:57:39 EDT 2023

Mrca

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From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> on behalf of J Mcvey via MRCA <mrca at mailman.qth.net>
Sent: Sunday, May 28, 2023 11:55:39 AM
To: Michael Hanz <aaf-radio-1 at aafradio.org>; , mrca at mailman.qth.net <mrca at mailman.qth.net>; W2HX <w2hx at w2hx.com>
Subject: Re: [MRCA] FW: R-45/ARR-7 Power Supply?

You should be able to find some standard type transformer that will supply the B+ and and 6.3V

The 24V can be a separate transformer. It might be hard to find a 18 to 20V AC one, though.
The solution would be to take whatever higher voltage ( 24VAC transformer will yield 33.6V) and regulate that with LM7824 three pin regulator.

All of this is probably laying around in your shop junk box. Very little $$$ involved.

On Saturday, May 27, 2023 at 11:06:23 PM EDT, W2HX <w2hx at w2hx.com> wrote:

Very interesting! Thanks for the tip.

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

From: Michael Hanz <aaf-radio-1 at aafradio.org>
Sent: Saturday, May 27, 2023 10:26 PM
To: W2HX <w2hx at w2hx.com>; , mrca at mailman.qth.net <mrca at mailman.qth.net>
Subject: Re: [MRCA] FW: R-45/ARR-7 Power Supply?

I wouldn't use 270vdc, Eugene.  Halli specified the same voltage as the SX-28() that the ARR-7 was derived from because it was all the data from that they submitted to the guv'ment for contract approval.  But guess what?  There is no push-pull high fidelity amplifier, which is the only reason the SX-28() required that voltage.  Check out the max voltages for the tubes in the ARR-7, and you won't see such a high voltage recommended by the tube manufacturers. It runs much cooler and with more stability using around 200-210vdc plate supply for the set.  Same goes for the AN/ARR-5 VHF set.  Try it, you'll like it.

73,
Mike  KC4TOS

On 5/27/2023 6:13 PM, W2HX wrote:

OOPS, That should be 270 VDC @ 135 mA not 2,700 VDC. Yikes

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

From: milsurplus-bounces at mailman.qth.net<mailto:milsurplus-bounces at mailman.qth.net> <milsurplus-bounces at mailman.qth.net><mailto:milsurplus-bounces at mailman.qth.net> On Behalf Of W2HX
Sent: Saturday, May 27, 2023 5:56 PM
To: milsurplus at mailman.qth.net<mailto:milsurplus at mailman.qth.net>; mrca at mailman.qth.net<mailto:mrca at mailman.qth.net>
Subject: [Milsurplus] R-45/ARR-7 Power Supply?

Hello friends.

I just acquired a nice ARR-7 that was electrically restored and aligned by a very competent fellow (pic attached). He made a 60 Hz AC-DC power supply for it, but it was crazy expensive. So here goes. The specs I need are:

2,700 VDC @ 135 mA

25 VDC @ 350 mA (for scanning motor, which is half the fun!)

6.3 VDC @ 4.0 A

Does anyone know if there is some existing power supply from some other piece of equipment that might have similar specs that I could begin hunting for? I know there is the PP-32/AR but my understanding is that this is a 400 Hz unit (380 Hz to 1,000 Hz).

If there isn’t another commonly available PS that would supply these, I may have to resort to building one. On ebay there are transformers with multiple secondaries but searching for such a beast is very difficult. Any advice on searching for a multiple secondary transformer? And of course, should all else fail, I could make a PS with 3 transformers if necessary.

Any suggestions welcome.

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

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Michael Hanz - KC4TOS

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