[Amps] SB 200 blown diodes in power supply

[Glen Zook]

Replace the diodes with 1N5408 which are cheap from Mouser and have a much better safety level than the original diodes.  Mouser does not have a minimum order.

http://www.mouser.com

You will have to increase the size of the holes in the existing circuit board to accommodate the larger diameter leads of the 1N5408.

However, you need to determine why the diodes "went".  Probably due to failing electrolytic capacitors.  You can get suitable capacitors from Mouser at reasonable costs.

Glen, K9STH

Website:  http://k9sth.com


--- On Thu, 3/24/11, Kathy Bookmiller <wb2aio at yahoo.com> wrote:

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.