[Heath] UPDATE Re: Heathkit HW-100/101 S-meter trouble

[Dick KF4NS]

Gentlemen,
One problem is solved, the constant S9+20, it was due to the replacement of the 2nd IF plate tap I made
to connect to the SB-610. I removed the coax and changed the coupling cap to a 10pf but left the loose
end floating on the bottom of the circuit board and that caused an interaction in the IF circuits and the 
S-meter to jump up.

If only that had been the end of it. After the cap removal I found a new problem. Now I get no AVC 
S-meter
reading at all. Rotating the RF Gain pot swings the needle top to bottom so the meter & RF gain pot is
good. I did all the voltage and resistance tests on all tubes that might affect the AGC/ALC and found
most very  close to spec. I did not dig into xmit-only circuits. Tubes all tested good. Soldered several
connections that looked suspicious. Relay 2 is working fine and cleaned contacts & tested for continuity.
CAL signal goes through on all bands (USB & LSB) as well as my sig gen signal at the antenna input.

I will now concentrate on tracing the AVC circuit back from the IF. If anyone has any idea what I should 
see as a level of AVC voltage compared to increased signal level, please let me know. Heath does not 
cover that bit of info. All I know is the level now is insufficient to move the needle on the S-meter.

Thanks and 73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow!


----- Original Message ----- 
From: "Dick KF4NS" <kf4nsradio at verizon.net>
To: <heathkit at mailman.qth.net>; "Heath puck list" <heath at puck.nether.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Friday, March 16, 2012 10:24 AM
Subject: Heathkit HW-100/101 S-meter trouble


| Ok guys, I am my own worst enemy lately. I can't seem to control my probe. While doing some testing in
| the IF section of my 100 for gain problems feeding my SB-610, I had my DMM probe on the B+ and while
| sweeping it away from the test point I caught it on a wire which caused me to lightly touch ground and
| heard a pop.
|
| Now the S-meter is messed up. Turning on the rig the meter swings to full then back down to zero
(normal)
| then immediately followed by a swing back up to 9 +20 and stays there.
|
| With all the settings adjusted according to the receive voltage chart I read -.8-15.8vdc (variable with
| the RF gain pot)  at the grid of V3 6AU6 1st IF and 289vdc on the plate, all normal. I read .52vdc at
the
| cathode. Swapped V3, tests good.
|
| At the meter pins on any band I read .25vdc on one side .32vdc on the other with no antenna attached.
If
| I touch the grid with a probe there is a loud squeal, no change at the meter. Meter and meter switch
are
| fine. CAL sig ON shows no change is meter reading (maybe cuz it would not normally read that high). No
| burned resistors in the circuit.
|
| What the H_E double L did I do this time? It has to be in the AVC circuitry.
|
| 73, Dick KF4NS
| St Petersburg, FL 33714 USA
| Keep The Glow!
|