[Hallicrafters] Re: Hallicrafters Digest, Vol 20, Issue 18

[Jerry Forwood]

>>Date: Mon, 12 Sep 2005 18:10:34 -0400
>>Joe W2KJ wrote:

>>From: "Joseph Trombino Jr" <w2kj at bellsouth.net>
>>Subject: [Hallicrafters] HT37 problem----solved?
>>First I tried a couple of 12AU7 tubes with no joy...then I tried >>two NOS 12AX7's with no joy and then from among the NOS 12AX7's I >>tried another pair and lo and behold I can null the carrier and can >>hear good SSB in a monitor receiver.

>>I can't explain why this is happening....I originally checked the >>12AT7 tubes in my B&K 747B tester and they indicated GOOD....and I >>swapped out the original tubes with NOS 12AT7's and still couldn't >>null out the carrier.
>>Why is this happening????  The tube called for is a 12AT7 not a >>12AX7...why didn't the several 12AT7 tubes work???
>>And why do only two out of four NOS 12AX7 tubes work???
>>I checked all of these tubes on my tube tester previously and they >>all indicated GOOD.

***
Could it be that all the in and out movement finally worked through the crud on the tube socket contacts?
***
>>OK...so now it appears that only one of the balance pots appears to >>nulling the carrier....the other pot does't seem to do anything yet >>the carrier is fully suppressed.......man, do I hate these old boatanchors (grin)
***
Maybe the pots need cleaning also?
***
73 de Jerry, KØEJF