[Hallicrafters] SR-2000 HUM PROBLEMS


James Liles james.liles at comcast.net
Tue May 31 21:28:14 EDT 2011


Hi John:
Yes the film capacitors are available in a number of forms.  I try not to antagonize folks but this needs to be said.  The orange dip and yellow tubular capacitors are available from Justradios and all are NON-INDUCTIVE Polypropylene or Polyethylene depending on the capacity!  I have measured their inductance and Q and the Polypropylene .001uf caps are self resonant at about 67Mc.  The ceramic X7R and Z5U .001uf are also self resonant at about 67Mc.  The striking difference is the Q is higher for the polypropylene film caps at self resonance.  The important issue is the common class 2 and class 3 ceramic caps should not be used in a circuit where you care about linearity or stability e.g. an analog or tuned circuit because their capacity varies with applied voltage.  The Hallicrafters engineers made clever choices when they chose caps for applications in the SR series radios.  

Please send the serial numbers as I am an avid collector of the numbers and owner history.  

Kindest regards Jim K9AXN

From: W4AWM at aol.com 
Sent: Tuesday, May 31, 2011 7:42 PM
To: james.liles at comcast.net 
Subject: Re: [Hallicrafters] SR-2000 HUM PROBLEMS

In a message dated 5/31/2011 8:14:05 P.M. Eastern Daylight Time, james.liles at comcast.net writes:
  The white 0v and the black 115v enter the radio and are attached to the transformer and switch both of which have no affinity to the chassis. 
Hi Jim,

Yes that makes it perfectly clear. I do let my tongue get in front of my eye tooth at times which prevents me seeing what I'm saying, Hi

As the codes tightened up in later years someone came up with the polarized cord set which prevented many nasty shocks. At the same time, someone got the idea of cutting the "wings" off of the polarized plug so that it could fit in older style sockets and someone else, maybe the same person, got the idea of using the 3 wire adapter plugs and breaking off the little grounding lug or cutting off the green wire. Some some simply cut off the "U" grounding blade. In the broadcast industry, we referred to these adapters as ground lifters so that we could lift the ground from a piece of equipment which was either causing hum to a mult box which provided many audio outputs from one source or was receiving hum from that source. Not exactly what the designers envisioned, but it worked more times than not. When it didn't, well, we won't talk about that in a public forum but it involved taking matters into one's own hands with a pair of dikes. That normally had a 99% success rate but made the competition very unhappy. I'm pleasantly retired from that rat race but certainly had fun many years ago.

On another subject, I'm the proud (read that broke) owner of four SR-2000s and three P-2000s. Unfortunately I have never had time to get any of them checked out or on the air.  One day I'll have to talk to you and see about getting at least one run through your restoration service. I can probably handle the PS myself but the rig requires more gear and knowledge than I have, plus the fact that I wouldn't want to screw something up.

BTW, I was especially interested in your comments about capacitor replacement in the SR series over the weekend. Someone worked on one of mine and may have done exactly what you cautioned about not doing. Are those caps still available if needed?

73,

John,  W4AWM



More information about the Hallicrafters mailing list
This page last updated 19 Mar 2024.