Hello

I have a Technics SU- CH7 amplifier and original speakers. I do not have any of the the other system components neither do I have the ribbon cables nor the remote. I have a power cable and when I power it up and turn it on it goes into stand by mode, the red light is on, but I can not get it to switch on. Is there a way to get it to work without the remote and the other components as would like to use it to play music using the inputs on the back.

Thanks

 

You need the service manual to solve this.

http://elektrotanya.com/technics_su-ch7_sm.pdf/download.html
..

 

How ?

 

The short answer is, you can't.

It's possible the amplifier won't do anything without receiving a digital signal from some part that's missing. I worked on a Bose subwoofer recently that was like this. I ultimately gave up on it.

Now, if you research the service manual and read what other users with your model have done, you might discover that it's simpler than that. Maybe there is a way.

No one here is going to know the precise answer unless by great luck there's another owner of that model here. Few here will do the leg work and research for you.

Did you get and read the service manual?

 

Thank you for your input

 

Thank you for your input

Did you find a solution to this problem.I have inherited the same amp and would also like to have it 'standalone'.
Any help/info would be appreciated.

 

Ha!
Im going to answer my own question.You need the tuner/sound processor from this system to power the amp.It has the standby button on it.Also the ribbon connector is needed.
Ps i have one for sale if interested along with the ribbon cable.

 

I've just picked up this amp from a street market - nice compact stand alone bi-amp, I thought. It even has an on/off switch at the back.Got it home powered it up but can't switch from Standby.

Can anyone measure what signal is sent via the ribbon cable to the amp (from the tuner) to activate the amp? I'm not willing to give up on this amp just yet! Alternatively is there a 'workaround' inside? (i.e. applying a DC voltage to pin 12 of IC601 for example)?

 

I've just picked up this amp from a street market - nice compact stand alone bi-amp, I thought. It even has an on/off switch at the back.Got it home powered it up but can't switch from Standby.

Can anyone measure what signal is sent via the ribbon cable to the amp (from the tuner) to activate the amp? I'm not willing to give up on this amp just yet! Alternatively is there a 'workaround' inside? (i.e. applying a DC voltage to pin 12 of IC601 for example)?

I offer my answer in #4 above. I think your odds are very low unless you can find some information to guide you. I wish I knew how to find such information. I suppose if you could find another complete unit somewhere, you might be able to reverse engineer it enough to get the incomplete unit running.

 

The answers you get will always change if the question changes. Your first reply to your original question pretty much says to use that amp with the other items the manufacturer intends for it to work with. We all knew that to start with.

We also all know that an amplifier amplifies, so injecting the right "analog" signal into its circuitry at the right point will produce an output which is amplified and sounds nice coming from a compatible output transducer (speaker).

Give us an accurate schematic of this amplifier, and we'll be able to pick out those points where power, input signals and output signals should be present. The best results will still come with the other systemic elements ("components") of the manufacturers intended system.

 

Hi Tranzz4md,

Thanks for your interest in this discussion. I am attaching the service manual of the Technics SU-CH7 amplifier.
Just a few notes:
1. The plan is to use the DAT input which is simply the normal audio connectors at the back (for an external analogue DAT source). I don't need to know the connections on the ribbon cable for the other audio devices.
2. I'm guessing that a digital signal is sent to the the amplifier from the tuner via the ribbon cable (via 'Bus Data' which is pin 4 on the 11 pin ribbon cable connector and pin 5 on the 13 pin ribbon cable connector). I suspect that this digital signal triggers the amplifier to switch from 'standby' to 'on'. A work around could possibly be to some how replicate a triggering signal on pin 4/5. In my previous post I though someone might be able to measure this triggering signal if they have the tuner that goes with the amp.
3. If the above is not possible then maybe there is a way to trigger the 'on' state internally. On page 26 of the attached file, it states that Pin 12 of IC601 is for detecting power on - could this be a clue to a workaround solution?

Thanks in advance for any ideas you may have!

 

I figured out , by looking at the schematic you can see that on the power control board F there are two jumpers that you need to bridge in order to make the unit to come on by itself without the tuner module. the board and the jumpers are close to the rec audio connectors inside the unit very accessible it is marked to the left of the fan on the top there is a small hole where you can see the two jumpers. they are part of CN901. What they do is to connect the ground to the power transistors making them to turn on the whole unit.

 

Hey Tony61. Wonderful to hear some news on the amp . Can't wait to dig the amp out of storage and try out your fix . will let you know if it works for me . thankyou for posting .

 

Hi Tony . I can't see the jumpers you are talking about . can u point them out to me please.

 

here 's some pics Tony. hope u can orientate yourself. cant find CN901

 

here 's some pics Tony. hope u can orientate yourself. cant find CN901

It's actually the test point jumpers behind the audio output terminals for the speakers labelled earth and power. You wi find underneath the AC input.

 

OK . Thanks for that info Cleo. Will take another look when I get back home in a few months . wish I had brought the amp with me now .

 

Hi Fred, you just connect the 2 jumper like this picture.it will be fine

 

Hi Fred, you just connect the 2 jumper like this picture.it will be fine

Awesome answer but we haven't seen Fred around here for over 4 years.

 

Hi Fred, you just connect the 2 jumper like this picture.it will be fine