Thread Rating:
  • 1 Vote(s) - 5 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco model 70 rebuild - by Tim P.
#76

Stinkkin intermittents! If anyone has ever dealt with one of these, you know what I mean! Anyways, I still have a volume coming and going issue. Thought I had it traced to the tuner HF trimmer - not. I've had to (more or less) table to project for now, and will be real hit or miss over the next few months as to how much I can get done as I am now 'owned' by my job for the season. About the only chances I will have will be a rainy Sunday afternoon.

I have spent quite a bit of time tracing things out, thinking the problem may be around the 1st detector area. I disabled the osc by removing the 27 tube, and have been connecting the gen at IF freq' to the grids of the different tubes up to the 1st af/2nd det. I get the most noted effect from the 1st det grid, and RF tube. Seems those two tubes work back and forth (one affects the other and vice a versa. ) It is difficult to tell since I think I hear some change no matter where I inject the signal, but it is most noted in this area. Could be that if a tube current is changing (due to a bad connection) it will effect others on down the line. I havent pulled the RF tube yet to run checks without it in the circuit.

All coils check, tubes swapped around, resistors, voltages, etc. One issue in trying to check things is checking plate voltages - kills the signal, then I cant tell if it is acting up when I am watching voltages.

I think I am down to resoldering connections and taking bakelites back out in the area to check my work. Any thoughts?

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 - 04-19-2014, 08:42 AM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Jackson 665 j2 schematic request
FIXED!daveone23 — 03:55 PM
Bakelite crack repair - what is best epoxy?
Thanks everyone. I appreciate you sharing your experience and looks like I'll work with the 24 hr two part clear epoxy....de371 — 10:25 PM
Jackson 665 j2 schematic request
Without a schematic its going to be hard tracing the wire wound spool resistors.daveone23 — 05:21 PM
Jackson 665 j2 schematic request
Looking for a schematic for the 665 j2 multimeter.daveone23 — 04:42 PM
Looking for place to donate unique Philco Philco J-1930 Prototype
>>I'll write to the Henry Ford. I heard, his secretary answers his mail, not he himself.morzh — 12:15 PM
Philco 48-200 alignment questions
Just checked the power cord and I did in fact wire it so the hot side (small prong) goes to the switch.transitony — 11:52 AM
Looking for place to donate unique Philco Philco J-1930 Prototype
Thanks for the suggestions.  I'll write to the Henry Ford.   That would certainly make sense since by the time this prod...jeibner — 11:49 AM
Looking for place to donate unique Philco Philco J-1930 Prototype
For what it's worth, the Henry Ford Museum and Greenfield Village in Dearborn, Michigan may be an option. The obvious ...GarySP — 11:39 AM
Help with Readrite 410 tube tester
Mike and I just had a short discussion yesterday about this very subject. So often it's the connections. Ya gotta have t...RodB — 10:08 AM
Looking for place to donate unique Philco Philco J-1930 Prototype
We have a regional museum here in the Twin Cities called The Pavek Museum. They have an extensive collection of communic...RodB — 09:30 AM

[-]
Who's Online
There are currently 2884 online users. [Complete List]
» 1 Member(s) | 2883 Guest(s)
Avatar

>