Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY
Yes, you probably were not feeding in enough signal to activate the AVC. You will need a somewhat strong signal as the 690 has a delayed avc circuit.
The 6J5 AVC rectifier cathode is biased a few volts positive, and the grid (used as the plate) is biased negative, so the IF signal amplitude must be high enough to overcome the initial bias before AVC voltage is generated.
The initial 2.4V negative bias applied to the grid of the 6J5 is what you are seeing on the IF 6K7 grids. It should increase with a strong enough signal.
Messages In This Thread
RE: 38-690 Code 125 - by Mondial - 01-05-2022, 05:59 PM
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
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 |
|
Preliminary work on wife's Silvertone 2014
|
| Hello roy,
that great news glad it worked out for you !!
Sincerely Richardradiorich — 10:50 PM |
|
Preliminary work on wife's Silvertone 2014
|
| Safety caps arrived today. Soldered one in and had a successful first power-up. No magic smoke escaped and it tunes in...glyphmon — 09:53 PM |
|
Who's Online
|
| There are currently no members online. |
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
