studer 810 with tape speed selector problem

[Rob Flinn]

Just been looking at a studer 810 with tape speed selector problem..

The speed selector is a rotary switch with 4 positions 3.75, 7.5, 15 & 30ips.  The switch just creates a binary number which feeds a 74 series logic chip.  It seems this just selects a clock divider elsewhere.

The problem is that the switch will only select 2 speeds which appear to be 7.5 & 30ips.  I have checked the logic feeding the chip & it is providing the correct binary to the chip.

The problem appeared after the machine was moved recently.

Anyone experienced this fault or know any tips ?

regards

Rob

 

[timshel!]

Hi Rob,

I had an issue with my 810 shortly after I moved it... one of the IDC cables in the back had come loose in transit and was causing some problems. It was a different issue to what you were experiencing, but I thought I'd just point out that the connectors aren't infallible. Popping the cover off the back and reseating the blue connectors worked for me, but without looking at the diagrams I'm not sure if this is at all relevant to your problem. It was only a 15 minute trip down the road as well...

Good to know there are other 810 owners out there.

Matt

 

[Rob Flinn]

Hi Matt

Thanks for that tip. I did reseat all those blue conns, but it made no difference.  It does seem like it has to be something like that but ........

This machine was just moved from one room to another in the same building.

 

[timshel!]

Hmm... looking at the diagrams. Sounds like a funny one... Are you sure you're getting the right signal on pin4 of IC3 on the speed control board? Wire point 102 should be 0v (short to wp107) at 3.75 or 15ips settings. Are you measuring this at the chip leg?

Assuming this is all good my next guess would be EL06 on the bus connector board. If you're missing one of your address lines then the serial data coming off the Master Panel won't be representative of everything it should be picking up... Are there any other functions that don't look like they're working properly? Can you switch between CCIR/NAB and Tape A/B settings correctly?

Matt

 

[Rob Flinn]

Hmm... looking at the diagrams. Sounds like a funny one... Are you sure you're getting the right signal on pin4 of IC3 on the speed control board? Wire point 102 should be 0v (short to wp107) at 3.75 or 15ips settings. Are you measuring this at the chip leg?

yes I am measuring it at the chip leg.

Assuming this is all good my next guess would be EL06 on the bus connector board. If you're missing one of your address lines then the serial data coming off the Master Panel won't be representative of everything it should be picking up... Are there any other functions that don't look like they're working properly? Can you switch between CCIR/NAB and Tape A/B settings correctly?

Matt

From memory the CCIR/NAB  & Tape A/B switches seemed to not be working.  It's not my machine, I was looking at it for a friend, who I can get to check this functionality tomorrow.

Thanks for taking the time to look at this.