Teac AG-V3020 amp, output problems. no sound, popping, faint phono sound

[neilc]

Hello all,
I have a Teac AC-V3020 amp that a friend asked me to look at. I used
to be pretty active on this forum but haven't done electronics work in
a while. I'm hoping the great people here can advise me on this one.

The most obvious problem is that the amp seems to have no sound
output. On further inspection, I noted that, when switcing between
input or dolby mode settings, it emits a strange sound, kind of a
combination of a buzz and a pop. This sound occurs consistently and
at the same volume regardless of the position of the volume control
and mute control. It also is not affected by speaker a/b setting or
direct source setting.

Another thing was noted - if a line level signal is applied to the
phono input, the sound comes through very faintly. It comes out
distorted and its volume can be adjusted by the volume and mute
controls.

I popped it open, checked all the fuses, noted no burns or damage to
the boards, solder joints look good, and the main transistors all test
within a normal range. I did not test the amplifier IC's because I
don't know what readings are normal.

I saw a previous post on this forum indicating that a possible work-
around to the no-sound problem is to set the amp in direct source
mode. Direct source mode has no effect in this case however.

Thank you in advance for any suggestions or advice you can offer.

-R. Neil Covington

 

[Arfa Daily]

Hello all,
I have a Teac AC-V3020 amp that a friend asked me to look at. I used
to be pretty active on this forum but haven't done electronics work in
a while. I'm hoping the great people here can advise me on this one.

The most obvious problem is that the amp seems to have no sound
output. On further inspection, I noted that, when switcing between
input or dolby mode settings, it emits a strange sound, kind of a
combination of a buzz and a pop. This sound occurs consistently and
at the same volume regardless of the position of the volume control
and mute control. It also is not affected by speaker a/b setting or
direct source setting.

Another thing was noted - if a line level signal is applied to the
phono input, the sound comes through very faintly. It comes out
distorted and its volume can be adjusted by the volume and mute
controls.

I popped it open, checked all the fuses, noted no burns or damage to
the boards, solder joints look good, and the main transistors all test
within a normal range. I did not test the amplifier IC's because I
don't know what readings are normal.

I saw a previous post on this forum indicating that a possible work-
around to the no-sound problem is to set the amp in direct source
mode. Direct source mode has no effect in this case however.

Thank you in advance for any suggestions or advice you can offer.

-R. Neil Covington

Nothing silly like a tape monitor button set, or missing link plugs at the
back ? You wouldn't usually expect to get any sounds of buzzing or popping
if either of those things, but sometimes, these AV amps can be funny beasts,
and it can be easy to be misled by such things. I have been many times, and
I repair them for a living !!

Arfa