Studer B67 Problems... Help

[jodal666]

Hi All

First Post here. So hello to everyone.

I have aquired some Studer machines... been in a basement for approx 15 years.
The first one I'm having a problem with ia a B67 Mk2 (B67-2-2.00 MK2)
Tape path cleaned prior to use. All in very good order :-)
When powered for the first time the unit played back tape through the onboard monitor speaker.

The next day there was no output from the speaker, although there is a slight hum from the speaker at ful vol. :-(

other transport control functions seem work correctly.

I've been looking through the service manual to check the supply voltages to the plugin boards connected to the basis board. the -12v is present at the board. but it doesnt get to the plugin cards (Pin14?) connected to the basis board. All other supply voltages seem to be present 5v,12v,0v. on the plug in cards

I've tried to follow the pcb track, but I cannot see where the track should go..

Any Ideas??

My eyes are starting to go fuzzy looking at all the green pcb track.

regards
Jodal666

[wintermute]

Hi and welcome! are the plugin boards edge connector or do they have header pins? Ether way you may have a contact problem on the connector.

Tony.

[jodal666]

Hi Wintermute

32 Header pins, What i find strange is the -12v is missing from all the plugin cards.
I'm thinking cracked track, dry joint or o/c component om the basis pcb,
An extension card would help to check the voltages on the plugun cards

Annotated pic of PCB
http://i10.photobucket.com/albums/a1...annotation.jpg

[wintermute]

I think your on the right track, I'm afraid my eyes aren't good enough to get anything from the linked board image. Time for me to get a new pair of glasses!!

If you have a circuit diagram, it may help you to track down likely components that may have gone O/C. It might also help with identifying the route of the PCB trace.

Checking with the power off and multimeter in continuity mode should help to trace the track.

Tony.