Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Philco model 70 rebuild - by Tim P.
#88

Ok, I dont want to get my hopes up just yet, but, I bypassed (subbed) the 70 ohm bias resistor to ground. I am not getting the flutcuations I had before. I do get fluctuations in the current draw, however, now they are smooth and slight. I reconnected the original resistor, and almost immediatly I noted the erratic fluctuations in current draw and volume. I have the sub back in. I am going to test this off and on for the next week before I shout victory or 'onward'...

I have tapped and swapped tubes. I dont think it is the socket. I dont get any change when I move the tube around. They seem good and tight in the sockets. I am getting the same thing on 2 different sockets, with 2 different tubes. The screen and cathode voltages are the only thing these 2 have in common.

Something else I noted is a wire 'whisker' between the open section of the bias resistor between points F & G. I read aprox 500k on this, and it is not on the diagram. Anyway, I will fire back if this has licked this irritating problem or not. Thanks for the advice.

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, 11:46 AM
RE: Philco model 70 rebuild - by Tim P. - by TV MAN - 05-05-2014, 11:03 PM



Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM

[-]
Who's Online
There are currently 1784 online users. [Complete List]
» 1 Member(s) | 1783 Guest(s)
Avatar

>