1. Home
  2. Electronics Repair
  3. Technics component stereo system from 1993

Technics component stereo system from 1993

I'm working on a Technics stereo system from 1993. It has a separate stereo tuner amplifier, SA-CH655,a CD changer, SL-CH555, and a stereo sound processor, SH-CH650. The components are interconnected with a flat ribbon data cable which connects to each unit in the back. The problem is that at medium to high volume levels the display will go blank, the sound will cut out and the unit will just stop working. It doesn't seem to "power down" because you need to power it down to "reset" this condition. These people really love this thing and very much would like to have it repaired but I don't want to make a career of it either. Does anyone have any experience with this condition on this model? Thanks, Lenny

Reply to
captainvideo462002
Loading thread data ...

Some of the Technics models from around that time, employ a fan which is a small DC motor much like a CD spindle motor. It is under an 'active' control system, and runs based on the music content and volume setting. It used to be a very common fault for these models to cut out at medium / high volume levels, just as you describe, due to the fan motor being worn and kicking up commutation noise, which then caused the system control micro to cut the whole system off. Full 'official' repair involved fitting a new fan, and adding a 0.1uF cap across its connections at the PCB, but often, just a cap fitted with the existing motor, would do the job.

Set the sytem running, and then advance the volume control until you see the fan start to run. If the system cuts out at that point or shortly after, that will (probably) be your problem, but be aware that most Technics models will also cut out if they see any kind of abnormal load across their outputs. I have seen a defective speaker also cause the symptoms you describe. It was perfectly ok at lower volumes, but as soon as the wick was cranked up, the cone dragged, and caused the system to cut out.

Arfa

Reply to
Arfa Daily

a

rol

o
e

up

ap

the

els

as

Thats really very interesting. It seems like you may have nailed it. I noted that the motor did seem to come on with volume setting as opposed to heat sink temperature. I also noted that the bushings on the fan seemed to be a little wobbly. I didn't pay it much attention at the time but now I'm wondering if that could be whats happening here. I'll try the cap tomorrow and see what happens. and I'll let you know. Thanks very much. Lenny.

Reply to
captainvideo462002

s a

ntrol

to

ume

ng up

e
d

cap

e the

,

odels

was

So far my first test with loud volume levels did not kick the unit off. I'll try again today, (while my wife is out of the house) and see but I think that its fixed. Thanks a bunch. Lenny

Reply to
captainvideo462002

So far my first test with loud volume levels did not kick the unit off. I'll try again today, (while my wife is out of the house) and see but I think that its fixed. Thanks a bunch. Lenny

No probs Lenny. Glad I was able to help. If the fan pulses and runs on the peaks, and the unit's not cutting out now, chances are that you have indeed got a fix.

Arfa

Reply to
Arfa Daily

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.