[Heathkit] HW-101 Low output on 40 meters

[Bwana Bob]

Miles:

Don't forget to peak the 40 meter heterodyne oscillator coil. It must be 
peaked in transmit mode. If it is a little off-peak, the receiver will 
work fine, but the transmitter will have low output.

			73,

			Bob WB2VUF

Miles Anderson wrote:

> This is a tale of two HW-101s -- one of which I have used for years in my
> own station (Rig #1) and the other of which I inherited from my
> father-in-law when he became an SK (Rig #2).
> 
> I had kept Rig #2 in storage for years, never operated it, and never knew
> much about its history except that my father-in-law built it from the
> original kit. I have no idea whether it ever worked according to Hoyle,
> though the builder's manual shows that he followed all of the tune-up steps
> and checked them off.
> 
> When I fired up Rig #2 for the first time into a dummy load, I got good
> output on 80 Meters, but everything above that was just about zilch. I went
> through driver coil the tuning procedure, and this brought the output on 20,
> 15 and 10 Meters up to par. Try as I may, I can't get the output on 40
> Meters above 70 watts.
> 
> The rig is entirely stock except that my father-in-law was never able to get
> a tin on the two steel shield partitions in the driver compartment. I had no
> better luck than he, so I replaced them with sheet brass, soldered to the
> comb rails on both ends, to the ground plane with a piece of tinned braid
> and soldered to the center pins of the tube sockets. I have also torqued
> down the screws mounting the driver board and the 6146 sockets to the
> chassis within an inch of their lives.
> 
> I have tried everything I can think of. I swapped the 6CL6 driver and 6146s
> from my good transmitter. I have double-checked the wiring, cleaned the
> contacts on the bandswitch, and even measured the capacitors in the tuned
> circuits. I have checked the other caps for leakage and double-checked the
> resistance values.
> 
> I have been careful in tuning the driver grid and plate coils, and the slugs
> pass through an actual output peak (so I know they are neither all the way
> in or all the way out). I used a VTVM with an RF probe to measure the signal
> level at the 6CL6 control grid, and it is actually higher than my working
> transmitter. Increasing the drive to the 6CL6 doesn't help. I get maximum
> output with the microphone gain control set about 2/3 open on all bands.
> 
> The only other thing possibly out of line is that the panel meter deflects
> negative when the switch is in the ALC position and the transmitter is set
> to TUNE. My other rig doesn't do this, but this rig does it on all bands.
> 
> I seem to have a problem in the 6CL6 driver stage, the PA or the
> coupling/switching between them.
> 
> Any suggestions?
> 
> Miles Anderson, K2CBY
> 16 Round Pond Lane
> Sag Harbor, NY 11963
> 
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