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Old August 24th 08, 03:15 PM posted to rec.radio.shortwave
Pete KE9OA Pete KE9OA is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 271
Default Kaito KA-2100 upgrade

I understand John.................actually, the power supply/regulator board
is a separate board that is held down with three small screws. The secondary
of the power transformer connects to two large pads on the board. The 1uF
100V non polarized cap can be soldered on the underside of the board.
Normally, the power supply diodes have a radiated power density that decays
pretty quickly above 600kHz or so. The manufacturer must have been using
some pretty fast switching diodes when they built this radio. The difference
after the mod is day and night.......it is as if a switch was turned off on
the interfering source.
When I had the radio open, I took a look at the loopstick antenna. It
appears to be the same type of twin coil ferrite that is used in the CCRadio
Shortwave. One of these days, I will dismantle it further and see if there
are any alignment points for the MW range. My unit droops in sensitivity
below 540kHz. This is typical of many radios when the loopstick is aligned
at 600kHz for the low end of the band. I also noticed this with the Sony
6800W.
If you could find a tech in your area, that person would be able to do the
power supply mod in about 10 minutes. If you need any more details, feel
free to e-mail me anytime at


Pete

wrote in message
...
On Aug 24, 4:11 am, "Pete KE9OA" wrote:
The built in AC power supply on this radio has quite a bit of switching
noise. Each of the diodes are bypassed, but they neglected to bypass the
secondary of the power transformer.
Place a 1uF ceramic cap across the secondary (input to the diode
rectifiers)
and this will eliminate that "light dimmer" type of buzz on the MW band.

Pete


Nice work Pete - that mains connection sure is a pest on MW.
Wish I lived near you to send it for that upgrade (unfortunately if I
try it I will ruin the radio and burn the house down)

JP