Re: {Collins} 30S-1 restoration

Hi Dexter,

Accessing the shelf is a pain in the butt.  However, I have found that with the main power transformer and rectifiers removed I could unscrew the shelf attachment screws and tilt the shelf enough inside the cabinet to gain access to do component work/replacement.  On bigger jobs, like you are planning, I would lay the amp down on its back side and work facing  down into the cavity ( I even raised up so that I didn't have to bend over too far :-) ).  It is not too bad and far easier than removing the RF deck.  Carefully clean all of the relay fingers with deoxit while you are at it (but be very careful not to bend the small fingers on K203).

Good luck...

73 de Mike

-----Original Message-----
From: Collins [] On Behalf Of Dexter White
Sent: Monday, December 29, 2014 11:31
To: collins@xxxxxxxxxxxxx
Subject: {Collins} 30S-1 restoration

Sometime back, while transmitting under power, I experienced a shutdown due to the main fuses blowing.  Poking around inside, I noticed that the bias transformer was charred badly.   In addition, I noticed that the plate transformer (version A with wires coming out of the winding) had a bare wire showing on one of the leads to V-201. 

I obtained a NOS plate transforment, T-201, from eBay (version B or C with binding posts) and tested it on my other 30S-1.  It works as designed.  I’ll install it in place of the original transformer which i sold.  

I’m now ready to replace some components on the shelf assembly (544-6880-000) in addition to the aforementioned bias transformer, T-203 which I obtained new from Hammond Manuf.

I’m planning to replace CR206, CR207 and CR208.  While I’m doing this, I might as well replace C209 and C210.  C203 looks like it has been leaking so I’ll replace it also.

Here’s the questions for the folks with experience who have gone before me:

1. To begin the process and make it easier to get access to these components, I’m planning to take off the upper cabinet assembly; is this step necessary, yes or no?  I’ve already tried to turn the shelf to gain access to T-203 and it looks tricky. 

2. Are there any other components that should be replaced (besides the ones that I’ve listed above)?  

3. When connecting the NOS plate transformer T-201 to V-201 and V-202, are there any special requirements for the connecting wire other than the voltage/current rating?

4. Any other suggestions?


Dexter White

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