Steve: The 6A10 is an excellent choice. I have been ordering components
from Banggood and have yet to have a problem. I just received the following
diodes, and have not put them in service yet. 2 A, 20 kV
PRHVP2A-20 High Voltage Rectifier Diode for less than $3 US.
They have other rectifiers, but no 6A10s.
http://www.banggood.com/search/rectifier-diode.html
--73, Mike, WV2ZOW
On Fri, Jan 29, 2016 at 12:25 PM, Jim Thomson <jim.thom@telus.net> wrote:
> Date: Wed, 27 Jan 2016 20:31:48 +0800
> From: "Steve Ireland" <vk6vz@arach.net.au>
> To: <amps@contesting.com>
> Subject: [Amps] Shunt resistors for a bridge made of 6A10 diodes in
> Alpha 91b
>
> G?day
>
> I am refurbishing the power supply board in my Alpha 91b and am going to
> replace the KD202P diodes which make up the bridge with 6A10 diodes (1000V
> 6A and only A$1.95 each).
>
> The original bridge had strings of five KD202P a side, with shunt
> resistors across each diode of 500K 1W. The stud mounted diodes are looking
> pretty burnt around the retaining washers/bolts, so it is definitely time
> (and I have a strange earth leakage fault).
>
> Please, I?d really appreciate some advice about what value of shunt
> resistor to use on each of the twenty 6A10 that will make up the bridge?
>
> PS The replacement encapsulated bridge rectifier sold by Alpha/RKR designs
> (5kV, 2A) is US$150, so this the reason for looking for a cheaper solution.
>
> Vy 73
>
> Steve, VK6VZ
>
> ## Dont put ANY shunt resistors across a 6A10. They don’t need them!
> It’s a series circuit, and the current through each leg of 5 diodes
> will be identical..whether frwd biased or not. Shunt resistors to
> equalize something that is already equalized went the way of the do-do bird
> years ago.
> I have been using 6A10 diodes for a long time now. They don’t requite any
> shunt components..and that includes stuff like .01 uf disc ceramic caps.
> You might want to use
> 6 diodes per leg, if they will fit. The wire leads out each end of the
> 6A10 ....IS the heat sink for them, so leave em on the long side if
> possible. They are typ 1250-1400
> piv when you test them. The 6A10 is a superb diode. I use it for
> everything from B+ supplies to safety diodes, and also strings of them for
> bias on GG amps.
>
> Jim VE7RF
>
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