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: 1 Guest(s)
[-]
Recent Posts
Heathkit Sweep Generator TS-4
Ron Instead of Quick reply, go to New Reply, then go to the title of the very first post, and change the title text the...morzh — 02:00 PM
6TPZ and 5TPO Radio Help
I am not a specialist in car radios. I suspect they might use vibrators to convert 12V to acceptable tube voltages, so ...morzh — 01:58 PM
6TPZ and 5TPO Radio Help
Welcome to the Phorum, R3Sons! I have very limited experience with car radios other than installing custom radios back ...GarySP — 01:08 PM
462ron
OK, I need to rename this thread to say..Eico 368 TV/FM Sweep Generator instead of the current title..Heathkit Sweep Gen...462ron — 12:49 PM
6TPZ and 5TPO Radio Help
Hello, I have a Philco (Ford) 6TPZ and a 5TPO radio.  I replaced the electrolytic capacitors in both.  I have the SAMS m...R3Sons — 12:29 PM
The list of my radio & TV collection!
Hello Peter, Thank you for posting that !! Sincerely Richardradiorich — 09:40 AM
Eico 232 VTVM Schematic
It's a microwave antenna. ?;-p?. I substituted 1N4002s off the 6.3 vac winding for the 1.5 volt battery. Uniprobe is the...RodB — 05:50 PM
Eico 232 VTVM Schematic
Try BAMA for a schematic. Looks like a replacement power source for the D battery has been installed. The tube may be...Chas — 04:51 PM
Eico 232 VTVM Schematic
Is that a battery holder?morzh — 04:43 PM
Eico 232 VTVM Schematic
A friend gave me this Eico 232 VTVM and I'm having trouble locating the schematic for it. This one seems to be a later v...RodB — 04:17 PM

[-]
Who's Online
There are currently 5355 online users. [Complete List]
» 1 Member(s) | 5354 Guest(s)
Avatar

>