Sony Boombox stuck in "tape" mode

[Mike S.]

My father-in-law asked me to look at a 2 year-old Sony boombox which he
said suddenly "doesn't work". It has a CD player, cassette player, and
AM/FM tuner. After playing with the controls I find that the CD player
reads CD's and displays appropriate stuff on the LCD, and the tuner also
tunes stations and displays the frequencies appropriately. But, in fact,
the only audio that gets to the amplifier is that generated by the
cassette player, regarless of what source is selected.

The switching between CD/tuner/tape is acomplished using electronic
pusbuttons. So you can select CD, and the CD spins, but the audio
that is routed to the amplifier is actually the cassette player.
The cassette player is controlled using old-technology spring-loaded keys.

So the thing is stuck in "tape" mode, even though the logic behind the
electronic controls think that the CD or radio is actually selected.
I'm still convinced that there is a mechanical switch or sensor that
became stuck somewhere when they last used the cassette player. How to
troubleshoot without schematic?

 

[William Sommerwerck]

So the thing is stuck in "tape" mode, even though the logic behind the

electronic controls think that the CD or radio is actually selected.
I'm still convinced that there is a mechanical switch or sensor that
became stuck somewhere when they last used the cassette player.
How to troubleshoot without schematic?

My guess is that there's an electronic switch (which is cheaper and simpler
than mechanical switches) that selects among the various sources. The switch
is probably blown, jammed at cassette.

You might try this... With the unit turned on, yank the batteries. This
might reset the unit.

 

[Ron(UK)]

My guess is that there's an electronic switch (which is cheaper and simpler
than mechanical switches) that selects among the various sources. The switch
is probably blown, jammed at cassette.

You might try this... With the unit turned on, yank the batteries. This
might reset the unit.

There may be a correct way to reset the micro - if that is indeed what`s
stuck - Usually a combination of key presses at powerup. A model
number would help?

Ron(UK)

 

[William Sommerwerck]

There may be a correct way to reset the micro -- if that is indeed what`s
stuck -- usually a combination of key presses at powerup. A model
number would help?

What I'm suggesting is "generic". I call it "CMOS lockup". I've seen it in
other products, including my NAD MR-20 monitor and a Pioneer LD player.
"Yanking the cord" while the power is on fixes it.

 

[Mike S.]

My guess is that there's an electronic switch (which is cheaper and simpler
than mechanical switches) that selects among the various sources. The switch
is probably blown, jammed at cassette.

You might try this... With the unit turned on, yank the batteries. This
might reset the unit.

Thanks; should have mentioned that I thought of that. It has never had
batteries inside; runs exclusively on the AC cord and it had been
unplugged for days.

 

[Mike S.]

There may be a correct way to reset the micro - if that is indeed what`s
stuck - Usually a combination of key presses at powerup. A model
number would help?

Yep, sorry. It's a CFD-F10.

 

[Mike S.]

What I'm suggesting is "generic". I call it "CMOS lockup". I've seen it in
other products, including my NAD MR-20 monitor and a Pioneer LD player.
"Yanking the cord" while the power is on fixes it.

Will give that a try.

 

[Mike S.]

What I'm suggesting is "generic". I call it "CMOS lockup". I've seen it in
other products, including my NAD MR-20 monitor and a Pioneer LD player.
"Yanking the cord" while the power is on fixes it.

OK. I've tried yanking the cord while the unit was running in CD, tuner,
and tape modes (with and without the tape mechanism engaged via the piano
keys). Unfortunately, no help. In each case, the unit powers up afterwards
in CD mode, but with audio still routed only from the tape player.

 

[William Sommerwerck]

OK. I've tried yanking the cord while the unit was running in CD,
tuner, and tape modes (with and without the tape mechanism
engaged via the piano keys). Unfortunately, no help. In each case,
the unit powers up afterwards in CD mode, but with audio still routed
only from the tape player.

Then I would guess you have a blown switching chip.

 

[Mike S.]

Then I would guess you have a blown switching chip.

Feared that would be the case. Anyway, appreciate the suggestions.

 

[b]

My father-in-law asked me to look at a 2 year-old Sony boombox which he
said suddenly "doesn't work". It has a CD player, cassette player, and
AM/FM tuner. After playing with the controls I find that the CD player
reads CD's and displays appropriate stuff on the LCD, and the tuner also
tunes stations and displays the frequencies appropriately. But, in fact,
the only audio that gets to the amplifier is that generated by the
cassette player, regarless of what source is selected.

The switching between CD/tuner/tape is acomplished using electronic
pusbuttons. So you can select CD, and the CD spins, but the audio
that is routed to the amplifier is actually the cassette player.
The cassette player is controlled using old-technology spring-loaded keys.

So the thing is stuck in "tape" mode, even though the logic behind the
electronic controls think that the CD or radio is actually selected.
I'm still convinced that there is a mechanical switch or sensor that
became stuck somewhere when they last used the cassette player. How to
troubleshoot without schematic?

open the unit and desolder the function select push switch. you never
know, a drop of liquid or deformed plastic may have it permanently
'on'.