It did turn out to be that 100uF 10V cap at the output of the 8V regulator.
After replacing this cap, the gain of the receiver jumped up to its normal
range. I replaced it with a 35V part.

Pete

Dont forget to short out that crazy 1K, 1W resistor that's part of the
internal speaker circuit where the speaker is driven through an
electolytic cap back to the + raw Vcc. I have no idea what this was
all about but you had to have a regulated supply or the unit would hum
due to any ripple on the raw Vcc.. Note that when an external speaker
is plugged in the circuit is now wired correctly to a real ground and
no hum from a non-regulated wall wart. I had to do this on both of the
HF-225s I had. I've yet to figure what Lowe was trying to do here.

Frank

Thanks Frank.............I didn't notice that resistor, but I've always used
regulated supplies on the radios. Probably why I didn't notice it. I never
was crazy about the internal speakers so I use a Minimus 7 on all of my
receivers.
Overall, it seems to be a good receiver. They are using what appears to be a
Bourns optical encoder. I am going to look at the schematic tomorrow and see
what they did differently and eventually change the encoders in my other
Lowe receivers to optical types. I think all I need to do is connect a
decoupled source of 5V to the encoder and remove the pullup resistors from
the Channel A and B tuning lines. If I remember correctly, there may be a
couple of series diodes in the tuning lines.
This receiver reminds me quite a bit of the AOR7030...........it will be a
keeper. I might sell or trade off the HF-225 if the right deal comes
along........not quite yet, though.

Pete


wrote in message
oups.com...
Dont forget to short out that crazy 1K, 1W resistor that's part of the
internal speaker circuit where the speaker is driven through an
electolytic cap back to the + raw Vcc. I have no idea what this was
all about but you had to have a regulated supply or the unit would hum
due to any ripple on the raw Vcc.. Note that when an external speaker
is plugged in the circuit is now wired correctly to a real ground and
no hum from a non-regulated wall wart. I had to do this on both of the
HF-225s I had. I've yet to figure what Lowe was trying to do here.

Frank