Studer A807 Mk1 command panel problem. Help required please

[jascha]

Hello dear friends,

(If you wish to reply in german it is no problem..i will translate it with google)

I have a Studer A807 Mk1 and unfortunately it has a fault that so far i have not managed to locate and would really appreciate your assistance.

This is my 2nd Studer A807. It is the VU version (meters on the front of the machine). The other i have is a Mk2 and is a VUK version (meters on a bridge), therefore internally they are not 100% compatible for fault tracing.

The problem with my MK1 model is that on the command panel, not all the buttons are functioning. The ones that are not functioning are the following:
Left and Right UNCAL buttons for both playback and input modes,
Left and Right MIC and MIC ATT buttons.

As i cannot get these functions to work i cannot use any uncalibrated level adjustments as the machine allows me only to choose the Line IN mode.

All the other functions are all fine. I wish to try and locate the fault but so far had no success. I have swapped most of the ics round on the tape deck controller with my other studer apart from the software and the eeproms but the only ic that made a slight change was IC 10 close to the Microprocessor. When this eeprom was swapped, some of the lights came into action but still i could not get it to function well. I have unplugged the audio cards to try and isolate the fault and also replaced some of the SAA1061s ( i believe) ICs on the command panel board but nothing changed.

Does anyone have a better knowledge of what's going on here please and what i should look at? The software on the machine is 8/88 i believe when it powers on. I checked all the PS voltages too and they seem to be fine. No fuses are blown either so all rectifiers are ok.

Any help would be hugely appreciated. I do have the necessary test gear too so i welcome any suggestions to try and locate the fault.

Many thanks

[erich]

Hello,

do you have a servicemanual ?

May be the setting of the jumpers under the keyboard is not correct.

greeetings

Erich

[jascha]

Thank you for all those who read my message and for any help. The confusing proble i had which is now sorted is that from who i bought the Studer machine, they had the awful idea of cutting the tracks in the circuit board on the command panel board to disfunction certain buttons.
It took me alot of time to find the fault.
I am angry at this as i bought this from Paris on ebay from a shop who sells alot on ebay and has advertised it as in Perfect Working order and obviously sold it to me faulty.

I will report him to ebay for bad trading with me.

Regards and thanks again

[erich]

Hello Jascha,

I had a few days ago the same problem with a dealer in UK. I bought also a Studer taperecorder.
In the offer was the sentence "comprehensively servived and aligned". I checked the recorder
and tried to discuss the problems with him. After two mails I got no more reply.

But that is the problem with eBay: if the parts you buy are not good, you have normally no
chance to get a compensation.

I am able to repair the faults by myself, but to get a compensation the costs ar too much.

greetings

Erich Schleicher