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Re: [Amps] Clipperton L

To: AMPS <>
Subject: Re: [Amps] Clipperton L
From: Alek Petkovic <>
Date: Sat, 22 Jul 2017 07:33:20 +0800
List-post: <>
Yes. The HV probe is the first thing.

Then, change out those metering resistors as well, while you're at it. Make up the 3 megohms with a string of smaller value, appropriately rated resistors.

It may bring your voltage reading back up to normal. If this is the case, then you merely have a soft set of 572B tubes.

73, Alek.

On 22/07/2017 6:41 AM, Jim W7RY wrote:
I would suspect the electrolytics. But without proper test equipment your just guessing. As suggested, a HV probe. And most good DVMs have a capacitor checker built in.

Good luck
Jim W7RY

-----Original Message----- From: Kelly Taylor
Sent: Friday, July 21, 2017 9:46 AM
To: Russ Williams via Amps
Subject: [Amps] Clipperton L

Update: just checked the transformer primary: appears to be fine (both halves).

Put it back together and turned it on again, and was surprised to see Vp now at 1700 volts, then realized that was in SSB, so it's still 1kv low.

At 1700 volts, I can get about 600w on 40,20 and 15. Which, accounting for efficiency, is probably right about what you can expect for 1kw DC.

So am I right in thinking all signs point to the HV circuit? Something in the voltage doubler? Could a leaky bypass cap (which is upstream of the ‘fuses’ (a pair of 1 ohm resistors paralleled and in series between PS and plate choke) drag down the voltage?

(In case you’re just arriving in this thread: yes, the primary circuit is wired correctly for 120v; no, the circuit board has not been rewired to accommodate 811s, no fuses blow and no smoke has been released (yet).)

73, kelly, ve4xt
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