[Hallicrafters] Hallicrafters Digest, Vol 102, Issue 21

[Tom OBrien]

Hi, I would first disconnect C20 (0,003 uf) check voltage pin 7 of v3 & pin 5&6 of v2 if v2 voltage is around 110V  & v3 is around 68V,
than replace C20 if not than check R17 (330 ohms). and I would replace CR1 with Sel Diode, and get rid of the Selimun rectifier. 
Good luck........Tom.....WA6EAN
 

> From: hallicrafters-request at mailman.qth.net
> Subject: Hallicrafters Digest, Vol 102, Issue 21
> To: hallicrafters at mailman.qth.net
> Date: Thu, 26 Jul 2012 12:02:22 -0400
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> Today's Topics:
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> 1. Need S-120 trouble shooting help (John Gindlesberger)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Thu, 26 Jul 2012 11:53:53 -0400
> From: John Gindlesberger <jhgphd at gmail.com>
> Subject: [Hallicrafters] Need S-120 trouble shooting help
> To: hallicrafters at mailman.qth.net
> Message-ID:
> <CAGYPZJHDhnjbwQXC3R5B-M6C6B+1rhqh9m5a=+Q6ZV0bZpMn-g at mail.gmail.com>
> Content-Type: text/plain; charset=windows-1252
> 
> I recently found a nice looking S-120 and brought it home hoping to
> enjoy a little SWLing, but after putting it on a variac and slowly
> powering it up, there was nothing--no noise or hum. All the tubes
> light up and I checked them in my less than state of the art tube
> tester and they all looked good. Thinking it must be a case of bad
> capacitors, I replaced all the electrolytics and black beauties. With
> the volume turned all the way up, there is now a faint noise and
> perhaps a very weak distorted signal from a local BC station, but
> honestly I?m not sure it?s even a station. So, I began to tracing the
> problem back and this is where I am:
> 
> 1. Voltage coming out of CR1 is 125
> 2. After R21 it?s 120 (130 indicated on schematic)
> 3. After R22 it?s 110 (120)
> 4. After R23 it?s 90 (110)
> 5. At V4, pin 7 has 110 and pin 6 90 (110 on schematic)
> 6. At V3 there is only about 0.25 volts on pin 7, but 68 volts is
> indicated. Going back to R13, on the lower side there is 90 volts,
> but on the other side of the resistor there is the 0.25 volt. I
> thought the resistor might be open, but it checks the correct value as
> do all the other resistors (within 10%) up to this point. The
> schematic says that R13 is part of a ?couplate?, but on this radio
> there was simply a 220K resistor going from T6 to pin 7. I did not
> see C17 which was supposed to be parallel to it. Also, it does not
> look like the radio had been worked on previously.
> 
> I could really use some patient elmering in fixing this one--marginal
> skills, but willing to learn! All suggestions welcomed.
> 
> Thanks
> John
> WA8FNJ
> 
> 
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> End of Hallicrafters Digest, Vol 102, Issue 21
> **********************************************