I've got the 30-amp switcher from the RV in line now, and things seem to
work ok.  All output power readings look good on both the TS590 and the
TMV71A.

I appreciate the offer to borrow the meterless RS35, but it's way too pricy
to ship, and not worth the effort, especially since I'm up and running
again.

I'll see what my local fellow hams say about working on my ailing RS35, and
take it from there.

I also still have a few other smaller supplies including the PS53 to run
things separately if needed.

So, lots of options here.

Tom Behler: KB8TYJ

-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Pat Byrne
Sent: Friday, November 27, 2015 9:16 PM
To: [log in to unmask]
Subject: Re: RS35 Transistors

Tom,
I agree with Butch - replace the pass transistors and the driver transistor
and you are probably good for another fifteen years.  If you would move to
Glen Ellyn or Wheaton I have a couple of competent friends who could do
repairs, but the way it is you are too damned far away for a lunch-repair
trip!
And didn't you say you had a 30 amp. switcher - should do all you need with
headroom and fill in until you get the Astron fixed.  I have an extra Astron
meterless 35 amp. supply you would be welcome to use, but mailing would be
pricy!  But it's here if you would like to use it.
PatAt 06:46 PM 11/27/2015, you wrote:
>Butch, Pat, and all:
>
>Well, after last night's test of my RS35 transistors, where I 
>discovered that the two transistors on the righthand side of the supply 
>became much hotter than the left while running the 590 with 100 watts 
>into a dummy load, I then decided to take some more power readings.  I 
>took the readings both with the internal meter on the 590, and with my TW1.
>
>You may recall that, the other day, the readings were 75 watts out 
>according to the TS590 meter, and 58 watts out according to the TW1, 
>and the supply meter read 13.8 volts and said I was drawing around 11 amps.
This time, the
>readings were better, meaning that   My output power readings were much
>closer to full power according to both the TS590 meter and my TW1.
>
>I then asked my sighted XYL to take a look at the meters on the RS35 
>power supply itself.
>
>Even though the voltage seemed to be at a constant 13.8 volts while 
>transmitting into a dummy load at 100 watts, my XYL noticed that after 
>a few minutes, the current readings on the RS35 ammeter began to 
>fluctuate.  They would fluctuate anywhere from 14 amps, to 18 amps.  
>When I checked the transistor heat sinks on the back of the supply for 
>temperature, I again found the same variation--the left-hand ones were 
>nice and cool, while the right-hand ones were almost too hot to touch.  
>Furthermore, my XYL noticed that when I touched the heat sinks, the 
>amperage values on the meter fluctuated as well.
>
>I don't mean to be obsessive about this, but this supply is making me 
>nervous.
>
>I think that I'm just going to bite the bullet and replace it, and then 
>take my time working with someone in my local club to see if we can fix 
>the supply so I can at least have it as a backup.
>
>I really would like to continue being able to run both my TS590 and 
>TMV71A with my rigrunner, so will be sure to purchase a supply that 
>would be adequate for the job.  I know some have recommended another 
>RS35, and I might just go with that, since I would prefer a linear 
>supply.  However, I'm always open to other recommendations if anyone has
them.
>
>In the meantime, I've got one or two  backup options, including the 
>TS53, to at least keep me on the air, both on HF and VHF/UHF.
>
>Tom Behler: KB8TYJ
>
>
>-----Original Message-----
>From: For blind ham radio operators 
>[mailto:[log in to unmask]]
>On Behalf Of Butch Bussen
>Sent: Friday, November 27, 2015 6:09 AM
>To: [log in to unmask]
>Subject: Re: RS35 Transistors
>
>The hot ones are likely good as they are in series with the load, that 
>is why those supplies are called series regulaters.  I'd replace all 
>four from the same vendor so you have sort of a matched set.  Should be 
>able to get those from mouser or some one.  You will also need some silicon
grease.
>When you pull the transisters, watch for the thin mica insolater that 
>is between the chassie and transister.  Some times these stay stuck to 
>the chassie, or heat sink, and some times they come with the 
>transister.  You don't want the transister actually touching the heat 
>sink.  A small bit of silicon grease is used between insolator and 
>transister and between tinsolator and heat sink to help with heat 
>transfer.  I'll have to see if I can find the number, but if I were 
>doing it, I'd go with darlingtons, I think e c g 247 or e c g 249 which are
the same, but higher current.
>73
>Butch
>WA0VJR
>Node 3148
>Wallace, ks.