[Amps] rocky point effect, barnacle bill
Sat, 24 Aug 2002 15:11:08 -0700
> I truly just don't know but I think I remember seeing a rectangular piece
>in the hv circuit [near the plate choke] that looked kinda like glass. Maybe
>that was it. ?
Rectangular power resistors are ceramic. They tend to make schrapnel
when they open. Wirewound glass-coated resistors are round. They can
withstand more joules of overload than similar rectangular ceramic
resistors. Glass-coated WW resistors are not as capable as
energy-discharge resistors but the cost is under 10% as much.
> The diode went from a trace on the qsk board to a ground trace. I
>should write these things down. I think it failed open but again I can't
> From what I remember from the manual, I have the feeling this diode
>is meant to fail under a fault condition.
The diode would not fail if it was rated at 200A-pk and a suitable glitch
resistor was used to limit fault discharge current to 200A. This upgrade
would have added about a dollar to the cost of mfg the amp and reduced
the chance of gold-sputtering from the grids.
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,