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Comment by Tom Jardine on November 23, 2013 at 6:37pm

Ha, very good! Actually it is (was) straight, the wide angle lens plays tricks. I can blame it on that anyway. I'll be anxious to hear how you proceed from here with the Berkshire. What model do you have? I wrote elsewhere on this site that I was young and stupid when I took the components our of a blond Credenza with the projection TV. It was somewhat neglected and in the living room of a very eccentric older man who turned out to be dying of out of control diabetes. He was a former banker, then record store owner in Phila, later retired, married to a younger woman who took to the bottle. The large house was filled with LP records and 78's, all three floors, every room. I bought a nice old Rek-o-kut 12BH turntable that I still have as well as hundreds of scarce records and this radio. Lots of interesting memories.

Comment by Timothy Murphy on November 23, 2013 at 5:19pm

Tom-

  Thank you. I do already have that and I agree with your description. That's why I'm looking. BTW, did you ever straighten the picture hanging above your 600b? Bests,

Tim

Comment by Tom Jardine on November 23, 2013 at 5:15pm

The service literature for the Berkshrie has several pages on it, but one would have to have a PhD in mechanical engineering and physics to do anything with it. I've read through it somewhat but it doesn't seem complete. It has numerical references to all the parts, but there is no parts listing. There is a lengthy procedure for repairing it. I don't have a handy way of scanning the document, otherwise I'd email it to you. I'll work it.  Tom

Comment by Timothy Murphy on November 23, 2013 at 3:32pm

Gentlemen:

   That makes 3 very good suggestions. I did not know about the thermal limit switch but it is probably not my problem. I did not know that the keys needed to be held in place and the literature does not mention this fact anywhere. The lack of a latching relay mechanism might have been a clue to me had I thought it through. The tuning knob set screw is in the literature, I am aware of it and I will reread that.

   Speaking again of literature, have you got a suggestion Tom, where to find printed info on the Collins in this set? I have been chasing this for about a year Norman, as you know. The military tech manual was for a very different Collins unit. 

Comment by Tom Jardine on November 23, 2013 at 10:37am

Timothy, is the motor engaged all the time now or trying to run continuously? Underneath the main tuning knob cap, see what appears to be a screw head. That must be tightened all the time except to mechanically reprogram the stations selected by the autotune mechanism. If that is loose while the motor is running for any reason, the autotune mechanism is thrown out of whack. 

Comment by Norman S Braithwaite on November 22, 2013 at 10:44pm

The push buttons on the Berkshire must be held down until the station has been reached.  For the manual function, the push button must be held down until the Autotune has cleared.  The Collins Autotune was designed for aircraft use and gave the allied forces a great advantage during WWII (quick, accurate transmitter tune for preset frequencies rather than tuning up several circuits before transmitting - communication could be completed before the enemy could locate the new frequency).  The RCA Berkshire is the only civilian radio ever built using the Collins Autotune.  I doubt that many changes were made to the Autotune for the small production required for fulfilling the RCA Berkshire requirement.

Norman

Comment by Tom Jardine on November 22, 2013 at 9:55pm

The thermal switch should open the circuit if the motor overheats and close the circuit again when cooled. It doesn't sound like you have that problem. On my radio, if I press the far right button (manual tuning) when I have previously used the automatic tuner function, the motor will drive the pointer all the way to the right and then back to the left and stop. You need to be pressing the manual button for the entire process until the motor stops. It is a very complicated little mechanism. Fortunately my Berkshire didn't have any problems with that except for the motor issue.

Comment by Timothy Murphy on November 22, 2013 at 8:46pm

I just saw the photo. Thank you. I notice the bronze bearing and woven wire cover. This is nearly aircraft quality. Nice.

Comment by Timothy Murphy on November 22, 2013 at 8:41pm

Hi Tom. I do not have the tuner on the bench right now so I'm working from memory. I would press a button at the far end of the keyboard and the motor would run the pointer all the way to the end of the dial and not stop. Then I'd have to turn the tuner off. Or, I might press a key in the middle and I could see the large gear nudge, but it would not turn.

     Thank you for the thermal switch suggestion. Would the switch make a noise when it operated. Does it self-reset? How long is a cycle?

     I understand what you say about removing the Collins assembly for bench work. The entire chassis has a level of interlocking mechanical design similar to a watch. It is not for Alzheimer's patients. I will be using my camera a lot.

Comment by Tom Jardine on November 21, 2013 at 10:15pm

Timothy, when you say it wants to run, do you mean you can hear it humming or trying to go? The motor has a thermal switch that opens the motor when overheated. My motor would run, but cut out almost immediately upon starting. The thermal switch was opening for no reason. I bypassed the thermal switch (after taking the motor apart) and it works fine. I had a dog of a time removing the motor though. I'll post a picture of the motor disassembled.

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