[Amps] Clipperton L soft

Russ Williams hrd998cc at yahoo.com
Thu Jul 20 21:51:26 EDT 2017

Is it possibly running on 120 volts but wired for 240?


      From: Kelly Taylor <ve4xt at me.com>
 To: amps at contesting.com 
 Sent: Thursday, July 20, 2017 3:06 PM
 Subject: [Amps] Clipperton L soft
Hi all,

Just trying to diagnose a weak Clip L. 

Here's what I see;
On CW, the Vp meter shows 700 volts. 
The transformer, when isolated, reads five ohms to the low-power tap and eight ohms across the entire secondary 
The filter caps each start out showing short then gradually charge to then read the 100k of the parallel resistor. 
The diodes read low resistance forward and out of range reverse.
The "fuses," two delicate resistors in series with the plate choke, and the choke itself, read very low in resistance
Thinking I shouldn't trust the internal meter, but wary of servicing it live, I checked the values of the three resistors in series acting as a divider for the meter (each is off by 30%). The meter shunt resistor, again, isolated, reads within one per cent of spec. 

I don't want to drop $300 on tubes only to find nothing's changed, and don't want to drop $100 on a Harbach kit only to find it was just the tubes all along. 

Someone's been inside here before me; the electrolytics are not factory and there's some not-entirely-professional soldering, but the connections all seem fine electrically. 

Is the off-spec condition of the meter dividing network just a diversion from bad tubes?

There's no evidence of any component having let out its smoke. 

73, kelly, ve4xt 

Sent from my iPhone
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