Browning receiver/transmitter DIODE PAC'S

[deltaqueenriverrat]

Question what are these diode pacs in each half of the Mark III's what's their function where are they located ?underside chasis? DQRR

[2600]

I assume you are referring to the black epoxy square with three wire leads on it?


Like thie one on the right-hand side of this pic from under the transformer in a Mark III receiver?




This part contains two rectifier diodes in series. You can think of it as one "half" of a full-wave bridge circuit. It's used to implement a full-wave doubler circuit, along with two electrolytic caps in series.

For the last 20 years or so we have been using a pair of 1N5408 rectifiers to replace this part whenever a radio gets all the electrolytic caps replaced. Just cheap insurance. The 3-Amp rated 1N5408 will not be damaged by a shorted part in the radio so long as the right size fuse is in place. The original "block" part was not that stout.

Like this:



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The one in the transmitter is on the underside of the chassis, just beneath the power transformer, on the tie strip nearest the fuse holder.

73

[deltaqueenriverrat]

Thanks 2600, that was the answer I was looking for, the radio I was interested in, the owner said one of the diode paks had failed so he replaced them with orig PD&E Diode parts in both the trans and receiver. Sure do appreciate your expertise here on the forum, DQRR