Re: {Collins} Collins 32S-3 Repair Success, took a long, long time!

I removed the band switch shaft in order to take off the coil shields.
As careful as I was with the wafer settings, I still managed to screw it up!.....

It took me quite a long time to get them back in sync. Next time I will mark the wafers BEFORE I remove the shaft.


-----Original Message----- From: Chuck Curran
Sent: Thursday, March 06, 2014 8:55 PM
To: 'Ben'
Cc: collins@xxxxxxxxxxxxx
Subject: Re: {Collins} Collins 32S-3 Repair Success, took a long, long time!


I cannot comment on anything but the one radio that I have experienced this issue with, all other Collins gear I have worked on and repaired never had this problem.

My issue started with a problem with intermittent crystal oscillator function, sometimes the oscillator provided a signal most of the time nothing. I putzted around for several hours, then simply clamped my scope probe on the output of the crystal oscillator tube, and proceeded to turn the band switch around. It became obvious that the crystal oscillator was not functioning on a consistent basis. OK, I should not have used a scope probe, now I have a fully functional HP 410B that does a better job measuring RF voltages.

So, after a few more hours of reviewing the problem, I thought the band switch shaft was slipping, the set screws were not holding it in proper alignment.

This was a false conclusion. It did nothing to fix the problem. So, I put my little headlight on my forehead, and started rotating the band switch, while watching the first wafer, which is the crystal oscillator wafer. The switch would turn, and after a bit, the rotating element of the crystal oscillator band switch element would finally also start to rotate, much later than the initial movement of the band switch knob. The ID of the crystal oscillator band switch rotating element was badly worn, for whatever reason. That was the cause of the first element of this problem.

I was quite pleased, thinking I had a solid grip on the issue. (FOOL!!) However, how should I now lock the band switch wafer rotating element into position, relative to the other four wafers? I just dabbed on some RTV silicon cement. Now I had the correct crystal oscillator signal output on every band (YEA), but the Driver Plate trimmer caps did nothing on all bands. So, I went back in and found that actually, all of the band switch segments from the mixer, RF amp and Driver plate were off. The point I picked to glob on some RTV to the crystal oscillator wafer was simply wrong. It aligned only the crystal oscillator band switch section, leaving the other four out of position. OK, us beginners have to learn the hard way-----

I then aligned the other four wafers which were all in sync, wafers 2-5, then tweaked in the crystal oscillator wafer into position to match the other four and put a touch of RTV on the crystal oscillator section. Now 100% are in alignment and the radio was easy to run through the standard RF calibration procedure, with lots of grid drive at the end of the story. Amazing how well the transmitter works when the band switch is in alignment as Collins Radio intended----

This was a wonderful experience, I feel I learned quite a bit. At the same time, it was nice that the other S-Line products, nine to be exact, had what I would call "basic" issue, nothing as demanding as this particular transmitter.

This 32S-3 is in great physical condition, nice cabinet and front plate, so now I will be selling it, I don't need three 32S-3 transmitters!!

On to the newly acquired 75A-4 and also the KWS-1!! Receiver is already perfect, so now to smoke test the KWS-1! Ah, that is next week, need to run a new power circuit to twin common shaft autotransformers to provide a 220 VAC power source, normal line voltage here is around 240 VAC.

My wife thinks I need consoling-----possibly with multiple Doctors?

Chuck  W9KR
Cedarburg, WI

-----Original Message-----
From: Ben [mailto:brloper@xxxxxxxxx]
Sent: Thursday, March 06, 2014 5:18 PM
To: Chuck Curran
Cc: <collins@xxxxxxxxxxxxx>
Subject: Re: {Collins} Collins 32S-3 Repair Success, took a long, long time!

I'm always curious how wafers get out of alignment. I know to remove the shields the rod comes out, is it a case of someone fiddling with the wafers are removed

The proper function of man is to live – not to exist.” — Jack London

On Mar 6, 2014, at 5:13 PM, "Chuck Curran" <ccurran@xxxxxxxxx> wrote:


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