[TenTec] Corsair I refurb project

[Mike Bryce]

Bill,

I have a few across my service bench. The failure on both of my unit have been the crystals not oscillating. A tweak on the capacitors got one to work, the other one seemed to have a flaky socket as it would intermittently start and stop.

First place to look is the low level driver going into the PA box. There’s a coax cable with a RCA cable  that goes into the PA.

I made a test cable, that I can plug the driver into a load and measure power. You’ll need to see about a watt or so at the output of that cable. If there is no power there, there’s nothing for the high level drivers and power transistors to amplify.

You can monitor PA current too, if it’s high and no RF, shorted driver or PA transistors. 


Let us know what you make out

MIke, WB8VGE


Mike Bryce, WB8VGE
 the heathkit shop
SunLight energy systems
J e e p
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> On Oct 24, 2015, at 10:27 AM, Bill Acito <w1pa at hotmail.com> wrote:
> 
> Must be Corsair week.  :-)
> 
> I have  a new-to-me Corsair I -- my winter refurb project. Good receive (mostly), good condition,  two primary issues:
> 
> 1.
> No RX 160 and 80: freq counter bounces around on  0.180 to 0.190 Mhz on
> these bands. I assume I should be looking at the wafer switches and 
> oscillators? All other bands are fine on RX.
> 
> 2. No power out on 
> TX -- zero.  Scope says I have good output from the low-level driver. Do
> the finals fail open? Do they both go together? Any easy way to check 
> if it's the drivers or the actual finals in the PA module?  I also read 
> that there was a common T/R diode fail that impacted ALC? What were the 
> symptoms of this fail?
> 
> Bill W1PA 		 	   		  
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