[Hallicrafters] New SR-2000

[Jeff]

Hi All -- I'm the proud owner of an SR-2000 -- SN 452002 843004.

I've got lots of work ahead -- it's cosmetically pretty good, but lots 
of the standard stuff needs to be done.

I'm working with Jim's (K9AXN) technical library and trying to soak in 
as much information.  I brought it up on the variac, and it does in fact 
hear, although not well.  It also puts out about 600 watts RF on low 
power, and reportedly has decent audio.

It's WAY premature to ask for troubleshooting help, since I've not done 
half the stuff I need to do, but I've got a quick question that I'm 
hoping might be answered with a simple "duh, RTFM" or other insultingly 
simple response.  When I hit the PTT on sideband, I see a resting plate 
current of about 250-300 mA.  I see voice peaks drive it up of course, 
but then the plate starts drawing current on it's own until the power 
supply protection trips and shuts it down.  It almost seems temperature 
related, but I can't say for certain.  It also could be a parasitic, but 
it's happening on 40 meters and I don't see any evidence whatsoever of 
overheating or abuse.  I haven't touched the finals or the 
neutralization since the rig came into my possession -- I'm assuming it 
worked "last time it was plugged in..."

Second question -- as I got through the supply, I'm seeing some odd 
stuff.  First, the bias capacitors (C315,316,317) are two 12 mfd caps in 
parallel.  It looks OEM, but why not a single 20 mfd (or 22 mfd)?  
Second, the diodes in the supply are 1N3487. I looked at the datasheet 
for them, and they show as 1500V .5A units, yet they are used in 
circuits with far less voltage and current.  Is a 1N4007 (which I have a 
drawer full of) an acceptable replacement?  Third, the screen filter 
capacitor (C314) in this supply is a 20 mfd, 500v unit.  The Schematic 
indicates an 8 mfd.  Critical? Fin ally, the plate voltage meter circuit 
resistors R313 and R314 have been replaced by what appears to be five 1 
meg carbon comp resistors encased in shrink wrap coming back from R312 
(which has been replaced with a chassis mount 50 watt 15 ohm resistor.) 
My plate voltage reads about 1.2 kV on the meter, so thinking that these 
resistors have drifted high.

I'm starting with the power supply of course!


Advice and war stories welcome!  I'm really excited about this rig -- I 
never thought I'd be able to get my hands on one.

73

Jeff

WB3JIH