AKSWL wrote:
Is there a soild state replacement for the rectifier tube 5U4 in a
HQ-145xc?

Seems I remember such a tube being available for around $20 from an
internet source.

73

John

Many, if not most, of the smaller (read: 5Y3, 5U4, 5V4, etc.)SS
replacements do not have a dropping resistor molded inside the unit.
I/we use a series of SS replacements up to and including the 3B28 and
4B32. The latter two SS replacements do have the resistors owing to FAA
purchase specs, however. Just be sure and include resistors in your
replacement design. As far as filament "stripping", as alluded to by
another posting, some say its a big deal. If the unit is not being
turned on and off many times a day, every day, I can't see it being a
problem.
The simplest thing to do is get an old octal tube base and solder in two
1N4007's. If it pleases you, fill it up with some Home Depot epoxy or
the like, just like the commercial jobs. Remember to hook the diode
outputs up to the correct DC output filament pin, as the Hammarlund
schematic indicats. Leave the other pin vacant, of course. While your at
it, try and keep the a.c. input voltage down to where the mfgr says it
should be, or a few volts less. High line voltage can really add to the
spectre of failures of vintage equipment



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