Sony TC135SD cassette recorder

[harryhomer]

Just rebelted my cassette recorder. What used to be an occasional thumping in the left channel is now there all of the time. It almost sounds a little like motoroboating, but maybe a higher frequency. If I push the stop button and hold it down, it goes away temporarily. Sometimes there is a little bleed of that into the right channel; but always predominately left channel. Would this be a bad cap in the power supply only affecting one side? I do have a schematic diagram for this unit.

 

[Chuck]

On Fri, 21 Jun 2013 10:42:40 -0700 (PDT), harryhomer
<mfiedl@comcast.net> wrote:

Just rebelted my cassette recorder. What used to be an occasional thumping in the left channel is now there all of the time. It almost sounds a little like motoroboating, but maybe a higher frequency. If I push the stop button and hold it down, it goes away temporarily. Sometimes there is a little bleed of that into the right channel; but always predominately left channel. Would this be a bad cap in the power supply only affecting one side? I do have a schematic diagram for this unit.

It is the record playback switch. If you can find one, replace it. If
not, Deoxit 5 squirted into the switch might repair it. This doesn't
work 100% of the time. It was such a common problem back in the day
we used to stock piles of replacement switches for all brands. Chuck

 

[Jamie]

harryhomer wrote:

Just rebelted my cassette recorder. What used to be an occasional thumping in the left channel is now there all of the time. It almost sounds a little like motoroboating, but maybe a higher frequency. If I push the stop button and hold it down, it goes away temporarily. Sometimes there is a little bleed of that into the right channel; but always predominately left channel. Would this be a bad cap in the power supply only affecting one side? I do have a schematic diagram for this unit.

Check the shielded wire from the heads, make sure the shields are
still connected.

Also, make sure the PC boards are firmly screwed down to the chassis,
the post many times have ground pads on them. You need to make sure
all bypass caps are still connected to ground..

Jamie

 

[N_Cook]

Chuck <ch@dejanews.net> wrote in message
news:3ig9s8tsbivr2qrp139buccb3n0hppvt3r@4ax.com...

On Fri, 21 Jun 2013 10:42:40 -0700 (PDT), harryhomer
mfiedl@comcast.net> wrote:

Just rebelted my cassette recorder. What used to be an occasional
thumping in the left channel is now there all of the time. It almost sounds

a little like motoroboating, but maybe a higher frequency. If I push the
stop button and hold it down, it goes away temporarily. Sometimes there is
a little bleed of that into the right channel; but always predominately left
channel. Would this be a bad cap in the power supply only affecting one
side? I do have a schematic diagram for this unit.

It is the record playback switch. If you can find one, replace it. If
not, Deoxit 5 squirted into the switch might repair it. This doesn't
work 100% of the time. It was such a common problem back in the day
we used to stock piles of replacement switches for all brands. Chuck

Agreed on that
As its such a work up to desolder these to disassemble and clean or even
replace. One last resort is to melt the solder points , in turn and with a
needle inserted in the hole , put a set on the common pins of each switch ,
so a different area of the contacts is used.
Sometimes its possible to remove the covers of these switches by bending or
cutting the tangs under the paxolin and removing , then cleaning the
contacts individually , and replacing the cover as best as possible.
Problem tends to be either compacted grease or build up of copper sulphide
insulating corossion

 

[harryhomer]

On Friday, June 21, 2013 12:42:40 PM UTC-5, harryhomer wrote:

Just rebelted my cassette recorder. What used to be an occasional thumping in the left channel is now there all of the time. It almost sounds a little like motoroboating, but maybe a higher frequency. If I push the stop button and hold it down, it goes away temporarily. Sometimes there is a little bleed of that into the right channel; but always predominately left channel. Would this be a bad cap in the power supply only affecting one side? I do have a schematic diagram for this unit.

Thanks all. I had long suspected it was one of the switches, but wasn't sure how to proceed; will investigate the approaches presented and let you know how I make out. Thanks again!