Monday, February 13, 2017

More restoration work on HW-100 and V-7 units


I wrapped up all the modifications moved on to replacing the broken rubber belts which couple front panel controls to variable capacitors inside the chassis. Later, when I get a mini jack, I will replace the large phone jack on the front for the headphones so that I can directly plug in modern headphones.

I am still waiting for one vacuum tubes and for the power supply, plus will need to restore the PS before power up. Still, I am working through all the resistance checks listed in the assembly manual.

 I did receive a direct digital synthesizer kit which I can use as a replacement for the VFO inside the transceiver, to produce a more accurate, stable and reliable frequency than the Heathkit oscillator. I will be wiring this up tomorrow.


Two potentiometers on the unit were frozen - they trim the zero and infinite ohms positions of the meter. While I have replacement units on order, I decided to disassemble one to figure out what caused them to bind up.

It turned out to be frozen grease at the point where the shaft enters the front of the pot, under a circlip that holds the shaft in place. When I removed the circlips and forced out the shaft, it dislodged the bad grease and allowed me to reassemble the pot which now had free movement. Electrically they work fine as well.

Thus, I will reinstall these original pots into the meter, rather than the new pots on order, but still need the replacement capacitors to complete the restoration. Those parts should arrive by the end of the week. I have received the probe kit to build the proper probes for use with the meter.


  1. I'm facing the same frozen grease on several sets of Sony floppy drives in a stack of HP-9122 disc (sic) units. I've had good luck with a light spray of electronic contact cleaner, patience, and minimal force; so far no disassembly has been required. Once the parts free up, I use a very small amount of Tri-Flow, a penetrating teflon lubricant that evaporates and leaves only teflon behind.

  2. Re the phone jack, you don't have to replace the jack in the panel, just use a mini-to-phone-plug adapter,