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Philco model 70 rebuild - by Tim P.
#46

Ok, alignment done (at least attempted). The good: It has REALLY brought it to life! It is MUCH louder. The IF was way off, and so was the LF osc. The bad: I still have issues in the higher freq's. Here is what I have so far. It seems much more selective and sensative below 110 on the dial. Above that, all I get is noise, motorboating and oscillations, depending on the location of the tuning cap.

It also goes microphonic at certain points. (That is, in the problem area - does NOT do this below 110 where things are working properly) I am guessing the HF oscillator is going out of whack at that point (I can about play the piano tapping the tuning plates). I have also checked for shorts on the cap. None found so far. I also could NOT get the #4 adjustment to go tune right. I have a lot of noise when adjusting, and it had a very weak signal (much more than low freq'). It just didnt respond like the others. Have to crank up the RF generator pretty high to hear. The others, I set the gen about as low as it will go. I have improved it a lot, but it still isnt right. I pulled the screws on the side with the adjustments and cleaned the contacts, put the screws back in. Seemed to help a little. When I get below 110, it kicks back in and I get stations and 'normal' static.

Mike, does your HF osc adjustment cap #4 have a small metal washer between the nut and tha cap? Mine does, the other 2 (#5 & #6) do not. Also, the tuning cap has bent out plates on the end. See my pic. You can also see the washer. This seems to be where the problem area is. I feel everything from the IF on out is working ok.

Here is a shot of the tuner - see what you think. Any help appreciated. Bout ready to call "Ghostbusters" Icon_confused
   
   

If I could find the place called "Somewhere", I could find "Anything" Icon_confused

Tim

Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44


Messages In This Thread
Philco model 70 rebuild - by Tim P. - by TV MAN - 01-29-2014, 10:46 AM
RE: Philco model 70 rebuild - by Tim P. - by TV MAN - 02-21-2014, 11:58 AM



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