[TenTec] Two Century 21 problems

[Tom NØJMY]

Well, we may have multiple problems here.  But I did get the audio 
back...for now.  I decided to check and see if there was any sidetone.

With a dummy load hooked up I tapped the leads from the power set switch 
together - had power our but no sidetone.  Don't know what possessed me, 
but I decided to take a listen through the headphones.  Voila, sidetone, 
and after tickling around a little bit I had some receive audio.

So I messed with the selectivity switch again and bingo, full audio!

Pull the headphone plug out - silence.

So, I guess I'll definitely clean that switch, then go after the 
headphone-jack/speaker circuit to see what gives.  I'd like to think 
that it was something as simple as a bad connection at the jack, or even 
if the loud signal from the calibrator just blew out the speaker. 
Things are never that simple, though.

Then I can try out some of the suggestions on my set-screws.

73,
Tom


Mike Bryce wrote:
> Tom...
> 
> for the tuning knob, try this.
> 
> Get a hunk of line cord from the junk box. take the coating off and pull 
> out one single strand of copper wire.
> 
> insert the copper wire into the screw hole, then the set screw. The 
> copper will give the threads on the set screw something to latch onto. 
> If the hole is really bugger up, you may need two strands.
> 
> as for the audio bug,
> 
> Scope the center wiper on the volume control. I bet the selectivity 
> switch may just need a good cleaning. A scope will tell if you have 
> audio at the selectivity control by looking at that center wiper on the 
> volume control.
> 
> if you don't then work your way back towards T2 on the #80356 board. 
> It's possible with extra large signals, you have some bugs in the d2-d5 
> diodes used in the receiver product detector
> 
> BTW... miserable board to get out of the radio!
> 
> 
> Mike, WB8VGE
> SunLight Energy Systems
> The Heathkit Shop
> http://www.theheathkitshop.com/
> 
> O
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>