[TenTec] Titan 425 Filter Caps and Noisy (Vibrating) Transfomers

[Jim Brown K9YC]

I just got off the phone with the guy at Ten Tec who works on the 
Titan 425's. 

I asked him about replacing all the caps if one is bad, which 
someone here or on another list had said was necessary. He said no, 
that is NOT necessary. Simply watch the plate voltage, and if you 
see it dropping, or if you get reports of hum, look for another bad 
cap and replace it. 

BTW -- it's pretty easy to check these caps with an old-fashioned 
ohmmeter. Hang the meter across each one for a few seconds to charge 
it, then reverse the meter. If the cap is good, you should see lots 
of charge and discharge current (that is, a low R value for both 
connections). If it isn't, you'll see a high value. Looking at one 
compared to the others will make the bad one stick out like a sore 
thumb. 

To quiet a noisy transformer, he says they shove a non-conductive 
shim between the windings and each side of the transformer core. 
I've got a noisy one, and I'm going to do that. 

One other point of information. R2 on the power supply rectifier 
board is shown on the schematic as 470 ohms. For a while, they were 
building them with a 20 ohm 25W resistor. He said it is now 10 ohms 
25 watts. The resistor is part of a surge protection circuit. 

73,

Jim Brown K9YC