HW100 nightmare

[Robert Groh]

Well, Dick, you are sure going to know your HW-100 back to front by the time you get done!  Frustrating now but (I hope!) satisfying in the end.

73
Bob Groh, WA2CKY




________________________________
From: Dick KF4NS <kf4nsradio at VERIZON.NET>
To: HEATH at LISTS.TEMPE.GOV
Sent: Wed, March 17, 2010 3:17:43 PM
Subject: Re: [HEATH-TEMPE] HW100 nightmare

Just a quick update. I actually made some progress finally. The trouble with the instability in the HET OSC was cured by simply replacing V19 12AT7 again, with a Motorola instead of the no-name one in there that tested great. A good example of the tube tester not being the ultimate determination.

To quiet down the chattering relay every time I tried to load on any band, I replaced the relay amplifier V12 IEC brand with a PRO/COMM and now I can tune all bands except all 10M bands which still only give 10W out if I am able to load it at all.

While looking into all the suggestions I decided to check everything again in the finals. Everytime I touched V8 (not the juice, hi,hi) the plate current pegged the needle. I turned it over and found pin 6 (cathode) to be intermittent. I cleaned the socket again and bent the pin terminal inward and that problem is solved.

I still cannot get the plate meter to read correctly. I must leave the bias adjustment full ccw to get the -65vdc in receive and -62vdc with the rig keyed with no drive. I replaced the two bad meter resistors and the 2 cathode resistors. Something is really screwy in that darn bias circuit.

I have checked and double checked all the areas that are common trouble for 10M. The other bands all load without any frequency error but on 10M I cannot even read a constant frequency and the relays chatter constantly. I checked the B+, LV and bias while the relays chatter and all dip just a bit using my VTVM.

That is all for now, I am still re-reading all the bulletins. Receiver section still works great.

73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow! 
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