HW-101 Strangeness

[Richard H. Arland]

Richard H. Arland wrote:

> Hi Gang:
>
> I'm in the middle of  reclaiming a HW-101 from the junque pile. Looks
> are deceiving.

> My current problem concerns the receiver breaking into oscillation on 15
> meters when trying to align the Driver Grid and Driver Plate PC boards,
> using the crystal calibrator signal (as outlined in the manual)

Many thanks to all of you who responded. Here's the latest in the HW-101
saga:

I pulled the IF board up from the chassis to put lock washers between
the ground foil traces around the perimiter of the PC board and the
chassis to insure good bonding and grounding. Someone had alread beaten
me to this trick!!

I reflowed the solder on the ground foil trace all around the board.
Then I bolted things back together using lockwashers between the PC
board and the chassis. (I also cleaned off the chassis in case there was
any build up of mung that might cause a poor bond.)

One glaring problem was that the +300VDC B+ wire coming onto that board,
and which also furnished B+ to the Driver Grid and Plate boards, was
cold soldered!  This might have been the problem all along (although I
don't see why 15 meters would have been the only band affected). Anyway,
time ran out before I could fire things up this afternoon, so it will be
Monday before I can have a go at the alignment again.

One thing that I did find by pulling the boards out of the radio, there
were a LOT of suspect solder joints. These were all reheaded to reflow
the solder "just in case".

This is only the receiver alignment...I can hardly wait to start on the
transmitter!

Thanks again to all who corresponded with ideas and support.

73 Rich K7SZ

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