On 01/08/2014 05:19 PM, Charlie Cunningham wrote:
Well, here in Raleigh, I've seen it go a good bit more than 5% high at
night. Still, I wonder if Bill could just put some higher voltage
electrolytics in there, tune for "maximum smoke" and "let 'er rip" - and
count on the key-down sag to keep the 6146s safe? ( Maybe I spent too many
years around electric utilities) I think that +/- 5% guideline is honored
more in the breach than in the observance. In the meter business "480
high-line" was 530 VAC!
73,
Charlie.K4OTV
Hi,
So far I haven't found the line voltage lower than 125 Volts and in
early afternoon it was at 130 volts. The transmitter was working and no
problem with the finals at all before I did the recap. I did the power
supply recap in all three power supplies because the low voltage supply
was getting really hot. I'm not sure what the high voltage was before
the recap so it may not be all that much higher now. The DX-100 worked
before. Somebody suggested using a Fluke DMM. Maybe that was inspired by
my comment about the front panel plate voltage meter. I don't have a
Fluke and I am not worried a bout a few millivolts. I did use a VTVM
when I wanted to know. The panel meter turns out to be close enough.
Two or three hams have mentioned the neutralizing circuit for the
finals. I would have suspected that too. But - the DX-100 doesn't have a
neutralizing circuit! I reread the entire assembly and operating manual
(I have the original). Nope. Not a word about neutralizing. No
neutralizing cap. No funny little wire to bend. Nothing. When I was
working on the wiring and removing/replacing caps I moved wire harnesses
out of the way. I thought that I put them back where they were. Probably
some of what I am seeing is because a wire or two is "sticking out" too
far. I did see a warning to dress the leads as shown *everywhere*. I
told you I reread the entire manual <evil grin>. I will configure the
high voltage filter cap(s) for the higher voltage and make sure the
wiring in the chassis looks exactly like the wiring in the pictures.
Nice to have all those big diagrams and pictures.
A few hams have suggested that the DX-100 is just a piece of junk
anyway. If it doesn't yield pretty soon I will probably make some
changes that update it to more modern circuitry (NOT SOLID STATE -
MRF454s, ETC). This one had the modulation iron and even the modulator
tube sockets removed by a previous owner. Some more modification won't
hurt much. Meanwhile I do have other radios to get me on the air. Just
not on Top Band.
Thanks for the comments and hints.
73,
Bill KU8H
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