NEVER replace one or two diodes in a string. You will be asking for trouble.
You should always replace the whole string of diodes with the same type and
preferably from the same reel/lot. Use any 1000V 1 amp diodes.
The capacitors in the SB200 can easily be replace on the same board that is
in there. Most of what are available today are the snap in type with
different pin spacing than the old caps in the amp. However if you spend a
little time looking at the board you will find that you will only need to
drill one small hole for each cap so that the pins will fit. They end up a
little offset from original as you use one of the old holes for each cap.
Each cap is rotated so that its new hole will fall on the circuit foil below
and can then be directly soldered to the board.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Kathy Bookmiller
> Sent: Thursday, March 24, 2011 11:46 AM
> To: amps@contesting.com
> Subject: [Amps] SB 200 blown diodes in power supply
>
> I know many of you probably consider a SB200 as a driver for your real
> amps, but for us QRPers, it is as good as it gets:)
> I just blew a diode in HV chain. Now one friend I respect says I should
> put in the Harbough board, soft start, etc. Trouble is, that's money I
> don't wish to spend if I don't have to. Put in new board is easy to say
> when you have money, but us poor underpaid nurses....
> Taking a look at mine, I noticed there are 3 diodes already replaced in
> the two strings by placing them under neath or on the bottom of the
> board. When I first looked at it, I thought they had been vaporized:),
> so this isn't a new problem.
> I'm hoping to find something at Radio Shack I could use and just change
> out the newly blown diode, maybe even using the trick the previous owner
> employed of just putting in the new one underneath to save taking it
> apart to get at the top of the board.
> So was wondering what you guys think or your experiences with the SB200.
> I just acquired it last summer and otherwise has worked really well when
> I've needed it.
> 73,
> Kathy, RN
>
>
>
>
>
>
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