KWS-1 Debug: Day 1

L – R: Siglent 1202X-E, KWS-1 with MFJ-267, Fluke 117, Hickok 533A. Not shown – Heathkit IG-102 Signal Generator

Nothing better on a gorgeous Spring day – (after an especially intense work week) to have some nice coffee and then to get crackin’ on getting the Collins KWS-1 transmitter back on the air. I’ll do it – damn it!


The simple, but effective Heathkit IG-102 Signal Generator

I called Howard, W3HM this morning and he guided me through debugging the KWS-1 problem. But I did do my “due diligence” and make sure that these things were OK – that they “cleared QA”:

  1. No blown fuses
  2. All tubes in Power Supply are good
  3. Relays in Power Supply are good
  4. My re-capping job is 100% good – without a doubt
  5. I very quickly learned how to use my new oscilloscope

That last one meant that I had to take a Heathkit IG-102 Signal Generator out and plug it into my scope – because I had no idea what I was doing. Thank God Howard has patience with me – but boy – did I learn so fast. Also – thanks to Bruce, AH0U, who gave me the Signal Generator . . .

I checked the VFO in the KWS-1, and yes, the VFO voltage changes when I turn the Carrier control on the KWS-1.

There is a signal on the Grid, Plate and Cathode of the 6CL6 Driver Stage – which means that it seems like the Driver Stage of the RF Deck is getting what it needs. Why there is no RF Output is still a mystery, and the latest theory is that it is a keying circuit. Howard also had me pull a 4X250B final amplifier tube and check the negative bias – but using my DVM probe on the center pin in the socket – and then turning the PA Bias knob on the power supply, and sure enough – it went from -97 to -41 volts

Two friends believe that the problem is in the RF Deck – and in the keying circuit. They both think something got jarred during shipping from Howard to me.

No – I don’t have the answer yet, but I feel the huge education really is the best part of this journey. I learned a lot today and feel really great. I’ll get this bugger on the air soon – I feel I am really close!




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