[BC] BC1H rectifiers for Paul

[John Lyles]

Paul
According the the schematic on my website here those are the IPA HV power supply rectifiers for the 807 stages. Since they are supplying ~600 volts DC then 2 kV PRV rectifier diodes in a full wave bridge configuration would be sufficient. It appears that the 1H used two modules that each had a pair of diodes in them, half bridges. To replace these with easily found diodes, go to your local Newark Electronics or Mouser and get 1N5408 silicon diodes and put two of them in each leg, using a total of 8 diodes. You stick four diodes soldered together in a string, all the arrows pointing the same direction. At the center between the second and third diode, connect the wire to the power transformer. Do the same for the second string of four diodes to the second wire from the transformer. Then connect the + ends of the two strings of diodes (the arrows point towards this) to the filter choke input lead and the other end of the diodes to the ground side. Circuit for each string would!
  look
like this:

(+) -----|<-----|<-----(AC from trans)----|<-----|<------  (-)

I see you can get 10 diodes from Mouser Electronics for 16 cents each! 
http://www.mouser.com/Search/ProductDetail.aspx?qs=qpnRKYi16JhwvlEVs0XJGg%3d%3d

You'd have them Monday if you order right now. Probably as quick as anyone can get them to you. 

Another source would be to us microwave oven diodes, which are found at repair shops. I don't know if Abbeyville has those... but they are usually good for 2 kV at least, and a half amp or so. They come in little black blocks, with a + and - terminal. In this case, you only use 4 total diodes for a full wave bridge rectifier. 

Here is my website info on the Harris BC1H1:

http://jtml.info
[click on BC1H and go to the bottom and select schematic for the BC1H or the solid state audio driver version, the BC1H1]

PS, its possible that the capacitor that is the filter in this circuit is going bad also, and that is eating your fuse, as usually diodes go bad fast, they are either shorted or open, not occasionally blowing fuses as yours appear to be. Or that you have an 807 breaking down, or not tuned properly and drawing excessive plate current. 

Best of luck!
John 



> Message: 35
> Date: Fri, 18 Apr 2008 14:32:11 -0400
> From: "Paul B. Walker, Jr." <walkerbroadcasting at gmail.com>
> Subject: [BC] Gates Transmitter Parts Needed!!
> To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
> Message-ID:
> 	<8bce0fe80804181132o71affd7fvdab5f9ec68354ea1 at mail.gmail.com>
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> 
> I am in need of CR42 and CR43 that go in the Gates BC1H Transmitter.
> 
> Mine has popped 4 fuses in 24 hours and my engineer (William Boyd, who is on
> this list boydsirboyd at aol.com) says those are the parts that are needed!