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Philco Model 81 Help - Printable Version

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+--- Thread: Philco Model 81 Help (/showthread.php?tid=13883)


Philco Model 81 Help - adiubald - 01-20-2016

Hi All,

New member- first time poster.

I have a model 81 that I have rebuilt. Replaced all caps, resistors and rewound the ant coil (primary side).
The speaker cone is in bad shape but it plays.

The set is working and I can get a local station in my basement- so I am not too far from finished.  
I have been making voltage measurements on the tubes to confirm everything is in spec and I am having a problem reconciling the 42 output tube with the rider voltage chart for this radio.  Specifically, the control grid CG to cathode K. The rider manual calls for 2.3 V.  The 42 tube data sheet calls for a control grid voltage of -16.5 to -20 v. I am measuring about -17 v from CG to K (ground).  Not sure if I have a problem or not.

My plate, screen and filament voltages are in spec. (riders chart).

thanks for the help,

Anthony

RE: Philco Model 81 Help - Kenneth F. Besso Jr. - 01-20-2016

  I say ,,,you are in the range between -16.5 to -20,,,sounds good to me

RE: Philco Model 81 Help - klondike98 - 01-20-2016

Welcome to the Phorum!
Icon_wave

If its playing well the voltage reading seems good to me. An alignment might be helpful as well.

RE: Philco Model 81 Help - Paul Philco322 - 01-20-2016

Anthony, you live in the same town as one of our members, Morzh! Good luck and welcome to the land of Philco.

paul

RE: Philco Model 81 Help - morzh - 01-20-2016

Tony

Where in Jackson are you?

RE: Philco Model 81 Help - Arran - 01-21-2016

 Perhaps it was an error? The control grid voltage should never be positive on any audio output tube that I know of, maybe it was supposed to be -23 volts rather then 2.3 volts? If it was actually 2.3 volts the output would sound like garbage if it worked at all.
Regards
Arran

RE: Philco Model 81 Help - adiubald - 01-21-2016

(01-20-2016, 10:56 PM)morzh Wrote:  Tony

Where in Jackson are you?

Hi Morzh,

I am on Autumn Avenue, between Diamond and Cobain roads. About 3 minutes from the Justice complex.

RE: Philco Model 81 Help - adiubald - 01-21-2016

Thanks for the help!

It does need an alignment (IF and the dial). Unfortunetly, the dial is brittle and in alot of little pieces. I ordered a replica replacement. When that comes in I should be able to do the dial and other alignments.

Yes, I'm in Jackson- near diamond road about 3 minutes form the Justice complex.

Also, I used to attend the NJARC meetings in Freehold with my grandfather until they moved to Princeton and Wall.

thanks again,

Anthony

RE: Philco Model 81 Help - morzh - 01-21-2016

Not too far, 6 minutes maybe. I am in a development by St Aloisius church, on Bennets Mills.

RE: Philco Model 81 Help - adiubald - 01-22-2016

(01-21-2016, 08:46 PM)morzh Wrote:  Not too far, 6 minutes maybe. I am in a development by St Aloisius church, on Bennets Mills.

Yes, I know that area. My Kids went to St. Al's.

-Anthony