Amen. After fixing several issues, including the filter cap issue, myself,
I sent the bias switching to TT c/o Paul Clinton, who got it fixed right in
pleasant surprises of cost and time.
Some time in the future, I'll buy another 425 for stn-2, now that I know
what to check out. Theyre good boxes for my uses.
73, Dave, N3HE
----- Original Message -----
From: "Jim Brown K9YC" <k9yc@audiosystemsgroup.com>
To: "Ten Tec List" <tentec@contesting.com>
Sent: Wednesday, October 31, 2007 2:18 PM
Subject: [TenTec] Titan 425 Filter Caps and Noisy (Vibrating) Transfomers
>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
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|