Technics SU-7100 Project - Need your help!

[grabread]

Watch out for dc voltage on the speaker terminals. This will kill your speakers ( may have done so already). May be best to just read everything you can on this subject and hold fire on the repair side for a while. I have put projects under my bench for a long while and come back to them when I have gained more experience.
Good luck.

 

[Artie]

I hate leaving stuff for dead.

Me too. That's why I took a chance bidding on mine even though they said it didn't work. But I got lucky on mine.

 

[slimecity]

Yea - the powerpacks are an issue with a lot of amplifiers.

The best way to find out if an amplifier has one is to brush up on your schematic-reading skills - when you see an amp for sale - go to hifiengine.com, download the schematic for that model to check it. Amplifiers with discrete seperate transistor outputs are the ones you want to get.

Dont worry, we have all been here - I have a small ghost-pile of amps that I scored, usually with other gear, only to find that they have stk modules, which I cant replace.

A lot of the Technics ones are quite nice however - if you score one with both modules working OK

 

[dspear99ca]

I have the service manual, I just can't make enough sense of it to use it correctly. I'll never figure out the problem, I can't test each part individually

Sure you can fix it. The question is, do you want to learn how to do it, is it worth the effort? Most of us - the ones who are not electrical engineers or electronics techs by trade - started off exactly where you are now. IF you want to learn, members of this forum will walk you through the diagnostic process. It will likely inspire you to do some reading and you will gain some understanding of how a solid state amplifier works. I have worked with electronics for decades, but still don't have the level of ease and understanding of how the various parts interact that many forum members have. Right now I am in the middle of diagnosing a receiver, and I started a repair thread on it because I needed some help.

If you have no interest in learning to repair and just want to flip it for a few bucks, I hate to say it but it's probably bound for the landfill.

 

[Bob]

now's a good time to start. fixing electronics is not the same as changing a tire
which only requires strength to remove nuts and pull wheel, speed (twirling),
and strength to mount tire and tighten nuts (except on a BMW 5 series).
this last item is HUMOR. Buddy's takes 150 foot-lbs. my nits can't
handle more than inch-pounds

if you eventually get it fixed, you then know a lot. BUT the far BIGGER
benefit is that you can now translate that learning prowess to other
things. like programming for a good living, stock market trading
for the ability to feed yourself for life.

 

[twilliams]

I'm going to take it to a local repair shop and see how much they would like to fix it. I would really like to have this working.

 

[eliot75]

Watch out for dc voltage on the speaker terminals. This will kill your speakers ( may have done so already). May be best to just read everything you can on this subject and hold fire on the repair side for a while. I have put projects under my bench for a long while and come back to them when I have gained more experience.
Good luck.

HI there, i have the same problem the right channel with ~78mv and the left ~45mv, how can we fixed to step down, ther is not variable resistor to do that in circuit