I used my HTX-252 for the first time last weekend, and was
told that the audio was muffled although intelligible. Anyone know of a cure
for this muffled effect?

Cal-

I also have one of the bargain HTX-252 transceivers. I had read here about the
low audio and expected that would be a problem for me as well.

What I found was that the radio has no microphone gain adjustment, just a peak
deviation adjustment, as has been discussed here. Checking modulation, I found
that it was working well with no further adjustment needed. It is just set up
to REQUIRE close talking to the microphone, and some people prefer to hold it
several inches away. The microphone element is located at the top front of the
microphone, so holding that spot within an inch of your mouth should give good
modulation without having to shout. During my testing I tried a couple other
similar microphone elements with no increase in sensitivity.

The only reason I can think of that would cause muffled audio, would be if
someone had gone into either the microphone or the transceiver's microphone
amplifier circuits, and tried to "fix" it! If you recently purchased yours and
it was the last one in the store, it is possible that it had been returned by a
previous customer. As such, it might have a factory defect, or it might have
been returned because of the failed attempt at improving it. Either way, your
best bet may be to take it back to a Radio Shack store along with the receipt,
and have them send it in for repair. I believe their technicians have seen
most of the problems many times, and should make fast work of a repair.

Per someone's suggestion here, I found service information for the Albrecht
AE-540 at http://www.albrecht-electronic.de/se...eurfunk/AE540/ which
appears to be almost exactly the same as the HTX-252. Following the microphone
audio path, there is a 2200 Ohm resistor that leads to the push-to-talk
circuit. That circuit is AC coupled by a 0.1 microfarad capacitor, to another
2200 Ohm resister, that connects to the audio processor integrated circuit. I
believe some increase in microphone gain would be achieved if that second 2200
Ohm resistor were shorted. However, the frequency response might also be
affected. As a wild guess, I would look on the bottom side of the main circuit
board for that 2200 Ohm resistor. It is located near a shield as I recall. If
you find it has been shorted, try un-shorting it and see if the audio improves.

By the way, I also checked www.mods.dk and found a suggestion to remove a
certain one microfarad capacitor to speed-up the radio's squelch response. I
decided that it was a better idea to replace it with a 0.1 microfarad
capacitor. As far as I can tell, that is the only worthwhile modification the
radio needs.


73, Fred, K4DII