Receiver will not respond to the power button. If I repeatedly keep pushing
the button the unit will eventually shut down. The same happens when trying
to turn it on. The receiver works flawlessly otherwise and while this is
happening all other buttons (am/fm/cd/mono etc) are responsive. Occassionaly
the unit will power up or down with only one push of the button. My first
thought was a bad/dirty switch. I removed the switch and sure enough it
seemed intermittent - sometimes reading 300-400 ohms when pushed other times
reading in the tens of ohms but never anyways near zero so I replaced it. It
still does the same thing. I traced the PCB traces and found were the
switch connects to the MPU (LC6554 I think ) and the signal is present at
the MPU going low each time the power button is pushed. I found a data sheet
on the LC6554 and hooked a scope to the OSC, Reset and Int pins and they
seem fine. Since it is a Teac programmed part I have know clue what the rest
of the pin functions are. I probably should just scrap the unit and buy a
new one but I really like the punchy sound this thing has. (I have a
borrowed sony hooked up in its place right now and its no comparison).
Anyway I was wondering if anyone has come across this kind of situation or
has any suggestions. Im sure I'd be better off if I had a schematic but
would hate to spend the time tracking one down and spending money on it only
to find that the problem is the MPU itself which I'm sure in non
replaceable/unavailable. One more thing - The remote for this is long gone
so I dont know if it would respond to the power button on the remote.

Thanks
Tony

Are you sure you don't want a service manual? They are $16.95 at this site:

http://www.servicemanuals.net/(u2vx2zvxqvzfxxvy50ifqtnr)/thankyou/teac.sm.all.html


"TG" wrote in message
...
Receiver will not respond to the power button. If I repeatedly keep
pushing
the button the unit will eventually shut down. The same happens when
trying
to turn it on. The receiver works flawlessly otherwise and while this is
happening all other buttons (am/fm/cd/mono etc) are responsive.
Occassionaly
the unit will power up or down with only one push of the button. My first
thought was a bad/dirty switch. I removed the switch and sure enough it
seemed intermittent - sometimes reading 300-400 ohms when pushed other
times
reading in the tens of ohms but never anyways near zero so I replaced it.
It
still does the same thing. I traced the PCB traces and found were the
switch connects to the MPU (LC6554 I think ) and the signal is present at
the MPU going low each time the power button is pushed. I found a data
sheet
on the LC6554 and hooked a scope to the OSC, Reset and Int pins and they
seem fine. Since it is a Teac programmed part I have know clue what the
rest
of the pin functions are. I probably should just scrap the unit and buy a
new one but I really like the punchy sound this thing has. (I have a
borrowed sony hooked up in its place right now and its no comparison).
Anyway I was wondering if anyone has come across this kind of situation or
has any suggestions. Im sure I'd be better off if I had a schematic but
would hate to spend the time tracking one down and spending money on it
only
to find that the problem is the MPU itself which I'm sure in non
replaceable/unavailable. One more thing - The remote for this is long gone
so I dont know if it would respond to the power button on the remote.

Thanks
Tony

You normally get that situation when another switch is leaky/shorting out,
thus preventing the micro running a small section of code loop. Perhaps
there is noise on the remote line from the sensor, again this could
interrupt the micro. As for a faulty micro or one with a duff port/rom, its
very unlikely. I havent a manual for anything similar to check pins etc.
also check supply rail for almost exactly 5.0volts

Good luck
AW

I'd want to check the reset line before I went any further.

Mark Z


"TG" wrote in message
...
Receiver will not respond to the power button. If I repeatedly keep
pushing
the button the unit will eventually shut down. The same happens when
trying
to turn it on. The receiver works flawlessly otherwise and while this is
happening all other buttons (am/fm/cd/mono etc) are responsive.
Occassionaly
the unit will power up or down with only one push of the button. My first
thought was a bad/dirty switch. I removed the switch and sure enough it
seemed intermittent - sometimes reading 300-400 ohms when pushed other
times
reading in the tens of ohms but never anyways near zero so I replaced it.
It
still does the same thing. I traced the PCB traces and found were the
switch connects to the MPU (LC6554 I think ) and the signal is present at
the MPU going low each time the power button is pushed. I found a data
sheet
on the LC6554 and hooked a scope to the OSC, Reset and Int pins and they
seem fine. Since it is a Teac programmed part I have know clue what the
rest
of the pin functions are. I probably should just scrap the unit and buy a
new one but I really like the punchy sound this thing has. (I have a
borrowed sony hooked up in its place right now and its no comparison).
Anyway I was wondering if anyone has come across this kind of situation or
has any suggestions. Im sure I'd be better off if I had a schematic but
would hate to spend the time tracking one down and spending money on it
only
to find that the problem is the MPU itself which I'm sure in non
replaceable/unavailable. One more thing - The remote for this is long gone
so I dont know if it would respond to the power button on the remote.

Thanks
Tony