Thanks Lucky! I'll let you know if I ever get bored with mine. As far as
repairing things, you are on the right track. It just takes time. Feel free
to shout me down directly if you ever have any radio questions.
About that HF225......the HF150 is better on MW if you use the Radio Shack
loop antenna into the high impedance input. I don't know if it is the way
that 12:1 transformer doesn't like the MW diplexer of if its ferrite core
material just isn't good on low frequencies. I did measure continuity, so
the RF transformer is good. On a long wire antenna, this receiver is great.
Measuring the sensitivity with an RF generator into the 50 ohm input, the
MDS is just under 0.1uV across the whole tuning range, which is the same as
the HF-150 when it has its whip preamplifier disengages.
A decent radio.
Pete
"Lucky" wrote in message
...
"Pete KE9OA" wrote in message
...
Another thing I discovered.....................somebody had replaced the
blown 1st mixer with some sort of ECG substitute. As a result, the gain
was about 20dB lower than expected. I popped in the correct chip
(SL6440C) and the receiver is working quite well now. Sensitivity is very
similar to the HF-150, as is system gain. Lowe came out with a winner
with this one.
If I get enough of these broken receivers, I may become a Lowe expert in
another 100 years.
Anyway, if anybody has some sort of problem with their receiver, feel
free to shout me down, using my e-mail address.
Pete
"Pete KE9OA" wrote in message
...
I picked up yet another "perfectly working" Lowe receiver. This one would
howl for the first 5 minutes of operation, the FM detector didn't work
for this time because of low I.F. injections level, and system gain would
be low during this time.
I traced the problem to a 100uF lytic cap near the audio amp. After the
unit warmed up, I hit several components with freeze spray. After I
found this problem component, I removed it completely and the problem
became much worse. When I tacked a cap into the circuit to test my
theory, the receiver started working properly. The cap must have been
leaky, because when I tried to parellel another cap across this one, no
change was noted.
This receiver uses the same audio amp as the HF150, so if you have a
receiver that howls even with an external speaker, this could be the
problem.
Between myself and some other friends, this is the 6th unit I have run
into that needs at least some kind of repair. It would seem that folks
get scared when these receivers start to malfunction, and "jump ship",
so to speak.
Pete
Hi Pete
I wish I knew more about diagnosing and fixing radios myself. All I've
done is replace some pots and minor mods and installation of items. I'm
handy though as I build computers.Thanks for the offer.
I'm looking for a 225 for my collection so I'm on the lookout for them. I
almost bought one from the U.K. but it didn't look that hot in the picture
posted.
Good going fixing that 225 up. There's nothing better then taking a
perfectly workable radio and restoring it to it's former glory.
Lucky
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