EMT 981 CD Player Troubleshooting

[BrianJSiegel]

I have the service manual which has all the schematics as well as a very handy set of self-diagnosing/testing functions which I have gone through and the unit has actually passed each one without a problem. But I can't seem to get it to do much when it's not in testing mode. Open/Close the disc drawer is about the only thing that seems to want to function.

Is there a special or specific way to operate this unit? I feel like I'm missing something obvious but I would guess it has to do with the configuration of flip switches on the rear-panel.

I can post some pics and other info later today - hoping someone out there might know something that'll save me on this one. Thanks fellas!

 

[Whoops]

you should try the diyaudio forum as it's more related towards to Hi-Fi equipment and enthusiasts

 

[BrianJSiegel]

you should try the diyaudio forum as it's more related towards to Hi-Fi equipment and enthusiasts

will do, much appreciated.

 

[moamps]

Does the CD spin the disc when you put it inside and close the drawer? Does the CD respond at all to start play and other buttons?

 

[BrianJSiegel]

Does the CD spin the disc when you put it inside and close the drawer? Does the CD respond at all to start play and other buttons?

It does spin for a few seconds but then stops - unresponsive to any front panel buttons except for the Open/Close

 

[OneyedK]

Is there a special or specific way to operate this unit?

*Turn player on
*Open drawer
*min-sec-diasplay should read diSC (this actually means NO DISK)
*Place CD and close drawer
*Depending on tthe CD, it can taka awhile to load, display shows init
*When ready, STOP-button will light.
*Choose the desired track by means of the rotating knob closest tot the drawer.
*Press START

If that doesn’t work, check the config switches (recessed in the middle of the rear pannel),
one of the options is to disable the front panel

Hope my memory is not too erratic as it is about 20 years ago since I touched a beast like that…
Beware of the CD drawer, the faceplate of the drawer in extremely sharp, can and will damage disks or body parts

 

[BrianJSiegel]

So I finally traced it back to a bad diode bridge rectifier in the power supply. It was the -15V. Just waiting for the part to arrive but was excited to post an update as soon as I found it

 

[Boomerang]

Some of the weirdest faults I have had over the years have ended up being dead or dying diodes in bridge rectifiers. So often things nearly work but have peculiar and irregular symptoms. One notable one was a Tascam 1" 16 track. I was called out to Twilight Studio who used to erase old multitrack tapes when the studio was not booked. He would just record silence on all 16 tracks. The fault reported was he could erase any selection of 15 tracks no problem, but recorded a buzz if all 16 were put into record. While I worked on the problem, he went to the far end of the building to make us coffee. The fault changed to be any 12 tracks OK, but any more than that there was a buzz. He came back with the coffee and it had reverted to any 15 again. I sussed that the kettle was the problem.... or at least revealing the problem. Much shouting up the corridor "switch the kettle on... switch it off" later, and several coffees, I found the leaky bridge. Just that small drop in mains voltage made the problem worse. Years later, an Amek Mozart in the Stone Roses' studio proved to be a similar problem. They were getting hum on the desk just at certain times of day. It wasn't actually the bridge this time but, by using the shower to dip the mains, I concluded it was probably the milking parlour at a local farm causing the daily droop in mains voltage. Changing all the PSUs to the 220V transformer tappings cured that one.

 

[BrianJSiegel]

Some of the weirdest faults I have had over the years have ended up being dead or dying diodes in bridge rectifiers. So often things nearly work but have peculiar and irregular symptoms. One notable one was a Tascam 1" 16 track. I was called out to Twilight Studio who used to erase old multitrack tapes when the studio was not booked. He would just record silence on all 16 tracks. The fault reported was he could erase any selection of 15 tracks no problem, but recorded a buzz if all 16 were put into record. While I worked on the problem, he went to the far end of the building to make us coffee. The fault changed to be any 12 tracks OK, but any more than that there was a buzz. He came back with the coffee and it had reverted to any 15 again. I sussed that the kettle was the problem.... or at least revealing the problem. Much shouting up the corridor "switch the kettle on... switch it off" later, and several coffees, I found the leaky bridge. Just that small drop in mains voltage made the problem worse. Years later, an Amek Mozart in the Stone Roses' studio proved to be a similar problem. They were getting hum on the desk just at certain times of day. It wasn't actually the bridge this time but, by using the shower to dip the mains, I concluded it was probably the milking parlour at a local farm causing the daily droop in mains voltage. Changing all the PSUs to the 220V transformer tappings cured that one.

Hah! That's interesting you mention that...I actually just found the problem to be the -15V bridge rectifier had failed! Good call on that! Exactly what the problem was

 

[pierre245]

Hello hello, i have a nice emt 981 fully working but can't use the varispeed At all. Is it a Switch to push to activate this function ? Thanks Pierre