Philco 37-84--no sound - Printable Version

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+--- Thread: Philco 37-84--no sound (/showthread.php?tid=4555)

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RE: Philco 37-84--no sound - sjhs1962 - 05-08-2012

(04-22-2012, 07:56 PM)7estatdef Wrote:  Half a meg is way too high. Volume is the wrong value. What you need is something around 10 to 30 k. This should work fine.
Terry
ps Did you get your -15v back on pin5 of the 6K6 which should be a 6F6

Here is latest update. I changed volume control to 25K. Volume was very low again. Then the AC switch on/off malfunctioned. I put back on the old VC switch. For some reason, I can't align this set. I get both RF and AF coming thru, but can't seem to get passed output meter reading. Instructions say to put meter on plate and cathode of output tube and set output meter to 0-30 volts. I get 250 volts when I do that. When I hooked up to voice coil, I got loud static! Confused???
Another issue is that radio works...when I keep the metal adjustment tool on the screw of the first trimmer. When I pull the tool off, I lose the signal??? Any thoughts greatly appreciated.

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RE: Philco 37-84--no sound - codefox1 - 05-08-2012

(05-08-2012, 10:45 AM)sjhs1962 Wrote:  

(04-22-2012, 07:56 PM)7estatdef Wrote:  Half a meg is way too high. Volume is the wrong value. What you need is something around 10 to 30 k. This should work fine.
Terry
ps Did you get your -15v back on pin5 of the 6K6 which should be a 6F6

Here is latest update. I changed volume control to 25K. Volume was very low again. Then the AC switch on/off malfunctioned. I put back on the old VC switch. For some reason, I can't align this set. I get both RF and AF coming thru, but can't seem to get passed output meter reading. Instructions say to put meter on plate and cathode of output tube and set output meter to 0-30 volts. I get 250 volts when I do that. When I hooked up to voice coil, I got loud static! Confused???
Another issue is that radio works...when I keep the metal adjustment tool on the screw of the first trimmer. When I pull the tool off, I lose the signal??? Any thoughts greatly appreciated.

Something really wrong here. I use a VTVM to measure modulated AC voltage across secondary (speaker) winding of the output stage. Digital meters will drive you nuts when trying to do alignment.

Also use an isolation transformer when working on transformerless sets and of course update your signal generator to 3-wire grounded state.

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