[Heath] Problems with HW-101

[Mark V Johnson]

Sounds like it's time to get the scope out. You've eliminated the VFO and
het osc crystals: vfo is OK on 80 and you said the Het Osc crystals are
putting out good voltage when tested at TP1. 

Sounds obvious, but make sure those 2 driver/preselector variable caps are
in sync, or phase. If they are out even slightly, you'll get the problem you
mention. Assume you've checked voltages?

Mark

VE3LU/VE3DJU

-----Original Message-----
From: Heath [mailto:heath-bounces at puck.nether.net] On Behalf Of Kenneth G.
Gordon
Sent: Thursday, December 17, 2020 3:18 PM
To: Heath at puck.nether.net
Subject: [Heath] Problems with HW-101

I am working on an HW-101 for a friend and have run into a problem I have
not seen before. 
I am not sure how to address this, so I am asking for advice here.

But first some history.

My friend bought the HW-101, with an HP-23 and a speaker, at a garage sale.
It was 
complete. He later found and bought a Heathkit desk-microphone at another
garage sale.

I completely rebuilt the HP-23 and it is completely up to spec.

I have cleared many problems with the HW-101. 

The first one was that the VFO would competely stop working after a short
warm-up period. I 
fixed that by replacing the VFO's FET, and replacing the VFO's voltage
regulator. The VFO is 
now stable and reliable.

Then, when I attempted it align the rig, following the manual's directions,
I found that I could 
not find any peak on either the grid or the plate coils for the driver on 10
or 15 meters, and 
the peaks on 40 and 20 were weak. 

The coils on 80 meters appeared to peak correctly.

I replaced the driver and final amp tubes with new ones.Then, when testing
for power output, 
if the rig was cold, power output on 80, 40 and 20 appeared to be close to
spec, but weak, 
but as the rig warmed up, power output would drop to zero.

Replacing the IF amplifier tubes appeared to fix that drop-out problem, but
things are still not 
correct.

I checked the heterodyne oscillator alignment, and all of those appear
correct. I reduced all of 
those to -3.5 VDC at the TP, although the manual calls for lower voltages,
and a maximum 
(apparently) at -2.0 VDC. I didn't think the higher voltage would hurt
anything, so I left that 
alone, as long as all were equal. I also tuned them all down on the slow
side of the peak as 
the manual orders.

Using the calibrator, I can get a reading of well over S-9, like 20 dB over
S-9, on 80, but only 
S-3 on 40, and no S-meter reading at all on 20 and up, although I can hear
the calibrator on 
all bands.

Power output in TUNE on 80 is close to 100 watts, although in the past, on
other HW-101s 
and SB transceivers I have worked on, the NORMAL power output on 80 has
always been 
110 watts. And this power output is only available with the MIC/CW LEVEL pot
all the way up

I can get about 75 watts on 40 and 20, but only 5 to 10 watts on 15 and 10
meters.

I have carefully examined all the wiring and soldering and can, so far, find
no faults in either.

What is bugging the heck out of me is that I cannot figure out WHY I cannot
tune the driver 
grid and plate coils at all on 15 and 10 meters. Everything LOOKS correct
there. All the coils 
appear to be the correct ones, but unless I can get the alignment done
correctly, both power 
output, and receiver sensistivity will be way low.

Has anyone run into a similar problem in the past, what did you find, and
how did you correct 
it?

Ken W7EKB


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