[Milsurplus] PRC74 finals/RF transistor type?

[Joseph R. Hogan]

Jim,
Unfortunately those Harris final RF pa transistors have been unobtanium for decades. There is not a direct cross. I was lucky enough to track down a NOS complete RF module to repair mine. A high antenna SWR will damage the PA. If you search online there was a transistor MRFxxx? you could use for a few watts out. Took some circuit mods. Others have talked about a redesigned PA to use a more modern approach using 12 vdc instead of the original 40 vdc boost supply. Hopefully others will chime in to help out.

It is a great man pack HF radio. Worth bringing it back to life.
Modifying it for selectable USB/LSB makes it even for useful.

Ra!ph W4XE

On March 26, 2019, at 12:03 AM, Jim Pruitt <jpruitt67 at gmail.com> wrote:

Does anyone happen to know if there is a common JDEC part number for replacement finals used in the PRC74?  I looked through the manual but it was hard to even find them on the computer screen.  A friend had found some web page (but did not give me the link--only a jpg of the screen shot so no clue where it was located) that said something about original parts from Harris were/are # 703075  and that someone had acquired a repaired unit that had transistor numbers 7230128038C  both of which appear to be manufacturer house numbers.  Can anyone tell me what the PNP final RF transistors are for the PRC74?

Thank you.

Jim Pruitt
WA7DUY
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