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: [email protected] <[email protected]> On Behalf Of W2HX
Sent: Saturday, May 27, 2023 5:56 PM
To: [email protected]; [email protected]
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