[TenTec] Corsair I refurb project

[Bill ACITO, W1PA]

Think I located it.
Finally had a chance last night to 
1) check the ALC diode on the SWR board -- it’s ok  
2) open up the PA module and take some voltages/transistor checks
Check both drivers and PA transistors using meter diode and resistive checks and no  power – look good.
Connect the power to the PA on the solder lug with the electrolytic and 
go to check diode drops on the PA board--  no 13.8;  none.  huh?
Check the outside of the lug – 13.8. Check the PA board – none. Repeat. 
Check the inside nut of the lug. None.  huh?
Let me say that again: one bolt, head outside reads 13.8, nut inside PA reads 0v.  
Tilt head to side like confused puppy.
Power off, disassemble.
>From what I can tell (and suspect), either at build, or on a previous repair, a “black metal” (anodized?) nut and screw were used 
to secure the lug to the PA cover. Over time and temp/current cycles, the nut corroded, and the subsequent current heating slightly 
melted the inset plastic spacer. Material and corrosion filled in between the solder lug and the nut on the inside cover, 
and isolated the lug from the nut and bolt threads... no 13.8.   Could have pushed me over with a stick.
Replaced hardware.
Unfortunately, in the process of diagnosing, I cracked the 100 ohm bias trimmer inside the module. I am waiting on the 
replacement before I close it up and apply power.
Cross your fingers.
Bill


>>On transmit with drive turned down, rig goes from drawing 1A to about 1.4A...   bias on finals seems ok.
>>Putting an ammeter in line with the drivers, no current (supposed to be 4 to 8 mA)...  bias adjust has no effect.
>>Looks like I lost the MRF476's, or the passives around them.