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

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

77 low volume
#1

While waiting for parts for my 87 I finished up my 77. All excited I fired it up. No volume until I touched the volume control shaft, top of the 1st rf tube (24), or the coil #5. Checked coil resistance 6.2 ohms from cap of 24 to gnd. matches other coils, volume control pod, ground connections, and voltages, all look ok. Ran a jumper from 24 cap connection on coil to ant. got a little better, but not as good as if you touch it. Some stations you can hear faintly, but others not until you touch. Tried swapping tubes, no difference. Probably something simple staring me in the face. Frustration got the best of me at this point. Any and all ideas welcomed. Thanks ahead of time, Richard
#2

Check for continuity in both windings of transformer #2;
Both sections of coil #5;
All three sections of coil #9 and #10.

Check for B+ on plates of both RF tubes. If missing on either plate, it's a coil winding associated with that tube.

(I assume you already replaces all the wax-paper caps and any out of tolerance resistors.)
#3

Hi Chuck, Thanks for the reply. #2 from volume center tap to gnd. 20.9 ohms, gnd. to tab for coil #5- 6.2ohms. Coil #5 center tap 6.2 and 6.1 ohms. Coil #9- 45.7, 6.3, 1.5 ohms. Coil #10- 48.5, 6.2, 1.5 ohms. B+ voltage on plates 154. All capacitors and out of tolerance resistors were replaced. Also before replacing anything there was a wire bridge on the bc resistor connecting H & J. I removed it since I could not find it on any schematics or updates. The resistor tests good between H & J 2,054ohms. specs. 2,000 ohms. Also a 24k dog bone resistor was in parallel with resistor #12 a 100k. I also remove it. Both seem to have been added a while back. Thanks, Richard




Users browsing this thread:
[-]
Recent Posts
The list of my radio & TV collection!
Yes, Michael. But strangely enough, I managed to keep the original veneer. I must admit that I don't really like it, so ...RadioSvit — 02:21 PM
The list of my radio & TV collection!
Good radio. I bet there was a lot of veneer fixing.morzh — 02:16 PM
Philco 46-480 Electronic Restoration
>> it is because I am retired and a little demented. You have just the right amount of it. No perfectly sane p...morzh — 02:14 PM
The list of my radio & TV collection!
Old Zenith 5S-29 tube radio. First turn-on after repair and reception quality testing. Demonstration of the operation of...RadioSvit — 01:27 PM
Philco 42-345 Restoration/Repair
Welcome to the Phorum, osanders0311!  Regardless how far you intend to restore this set, first priority should be replac...GarySP — 11:51 AM
Philco 46-480 Electronic Restoration
Joseph, it is because I am retired and a little demented. My problem is that I wanted to own a collection that spans th...MrFixr55 — 11:29 AM
Philco 46-480 Electronic Restoration
Wow, here I am with only two restored radios. I’ve got to boost those numbers! If you can’t run with the big dogs, you m...jrblasde — 10:04 AM
Philco 46-480 Electronic Restoration
Hello MrFixr55, That will for sure keep you out of trouble! Last Sunday was spent mostly doing yard work anyway the we...radiorich — 09:50 AM
Philco 46-480 Electronic Restoration
Throw in all the Audio equipment that has to be kept in a bedroom (my office)L. 8 portable self contained PA speakers, ...MrFixr55 — 07:40 AM
Philco 42-345 Restoration/Repair
Looking at the pic supplied by Rod B, you can duplicate the missing loop antenna. 10 gauge copper wire can be used to m...MrFixr55 — 01:20 AM

[-]
Who's Online
There are currently no members online.

>