[Hallicrafters] update SX-101 resistors

[Jim Wilhite]

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