[Milsurplus] TCS-8 has gone SK

[Falls, Jim]

My beloved TCS-8 receiver has gone silent and I need advice as to where to start digging. 

Symptoms came on from one day to the next and this may be the root of the problem: I used an ARC-5/R-23 the other weekend during the CW contest (11-4-06) as a Q-5er. Worked very well. I looped 3 turns of bare phone wire (3/8 inches max) around the plate pin on the 1st IF tube, plugged it back in carefully and ran the insulated remainder out thru the louvers on the side of the case up to the R-23. 

I (now) realize I had B+ on this wire (D'oh! It's the plate, after all). Maybe a short to TCS chassis if the wire got yanked? 1st IF amp tube tests OK. 

I probably should've just kept the wire insulation and gone w/capacitive coupling, right............? AAArrrggghhhh! 

Anyway - here are the symptoms:

1- Originally, the problem was intermittent, very weak AM signal. I could pick up occasional stations in CW mode when I'd wiggle the band switch. If I moved the tuning crank, or tapped the front panel, the signal would vanish and I'd have to wiggle the switch again. Cleaned all band switch contacts, found an intermittent tube in the CW OSC section (this rig has a 2 tube add-on box, one of which is a 12H6) and replaced it w/a good one to no avail. 

2- I am getting audio out - I can hear faint clicking as I move the bandswitch; faint hum from the PSU at full volume. 

3- NO noise whatever when I tap the antenna lead against the ANT jack or move from AM to CW or use the RF GAIN control. 

So far, I have checked both IF coils for continuity (Thanks, DX'er) and they appear to be good (unless an adjustment cap is now shorted). Haven't pulled the covers yet.
Cathode and screen resistors on 1st IF tube measure within tolerance.
I may use the R-23 to see if I'm getting 455 IF out of the transformers as before. Maybe it's further up/down the line.

Schematic for the TCS-13 (Thanks, WS#19!) shows 3 caps across the main tuning cap gangs. Two of these appear to be micas (C224, C225) the other one (C219) is cylindrical (1.8 in. diam) w/radial leads. Could these be the problem if shorted? 

Seems like the AF is working, just has nothing to amplify....... 

A little knowledge can be a BAD thing sometimes.

:=(
Jim Falls
KG6FWT
Eureka, CA