[Hallicrafters] update SX-101 resistors

[Robert Sauvan]

Great advice Jim,

I do run all of my boat anchors on a regular basis. I fire them up 
whether or not I put them on the air or not. I do that mainly just to 
make sure they are still working. I have a couple I like better than the 
others but love them all regardless. I was curious as to what kind of 
resistors I should use to replace the old ones while I was checking out 
the radio. We have a place in Boulder Colorado called "JB Saunders". 
They have a very large supply of carbon composition resistors like the 
ones in my radio. I have been buying them when needed and they all seem 
to check out fine and work fine. So far anyway."Just Radios" is another 
place I have bought numerous caps and resistors but they have a $25.00 
minimum so JB Saunders works out well for small purchases. It would 
really be nice to listen to a radio that has been restored and the owner 
feels it is good as new. I do feel the radio I have is working great, 
but still think it has room for improvement. I will see how it goes over 
the next few weeks and maybe start picking up some new resistors and 
slowly replace the old ones as time goes on. I know many of the guys I 
speak with say "if it aint broke,dont fix it". I kinda agree, but after 
replacing all of the caps in this radio and seeing how much better it 
runs and sounds, I think a resistor overhaul would be fun and nice to 
see how much improvement it shows. It isnt all that hard to do and 
components that are nearly 50 years old have got to be wearing out if 
not now, certainly in the near future. Im one of those guys that think 
something works good, but I think it can work better. So, with that 
said, we will see how the next few weeks go with this thing and I will 
let you all know how it works out. BTW, would love to qso with some of 
you sometime soon. I will admit, Im pretty much a cw guy, but do like to 
get on phone occasionally just to brag that I am using 50 year old 
equipment. It cause some nice pileups believe it or not.


Thanks-Bob-W0YBS




On 5/31/2014 7:35 AM, Jim Wilhite wrote:
> One last thing on the resistors Bob.  I would use the receiver for 
> about 3-6 months turning it off and on daily and being sure it heats 
> up and cools off many times.  Then check the resistors again.  I have 
> found that they have a habit of checking good then as they heat and 
> cool, drift.  I am not saying they will just that I have seen them do 
> that.
>
> Most of those who exhibit that property were made by IRC.  The later 
> versions of the Allen Bradley do not seem to have that problem as 
> much.   I have a receiver here that the screen resistors in the audio 
> section checked good then after a few weeks of use it didn't sound 
> quite right.  Among the problems, I found those resistors had drifted 
> up in value significantly and at very different values and they were 
> Allen Bradley.
>
> One other thing.  When replacing resistors be careful what you use.  
> You can still buy carbon composition resistors from some suppliers but 
> those I have bought, many are way out on value. Also be careful to not 
> use metal film in places that deal with RF.   If they couple RF from 
> one stage to another they can fowl up the works.  In those places it 
> is best to use ceramic.  If the circuit is purely a DC circuit, then 
> the metal resistors will be OK, but be careful in your choice.
>
> Jim
> W5JO
>
>
> -----Original Message-----
>
> Well,
> I got up very early this morning to dig further into the receiver
> resistor checking. I marked 5 resistors that I felt needed to be looked
> at closer. Actually, only 1 I thought registered a bit high. The others
> were very low. I was told these were probably low due to being in a
> circuit. I flagged them anyway. Remember, this is a learning thing for
> me. So, I clipped all of the resistors out of circuit only to find they
> checked just fine. I ended up soldering them back in. None of the
> resistors looked as if they have ever overheated. In fact it really
> looks good under the chassis. At this time, I dont feel I have any
> resistor issues and am going to leave the radio alone for now. Its
> working great and if something pops up, Im a little closer to knowing
> how to troubleshoot it, and any of my other rigs in the future.
>
> Many thanks to everyones help, I think Im getting the hang of this.
> After you guys have taught me everything I know, then what!!
>
> 73-Bob-W0YBS
>
> .
>