GELÖST - STUDER B67 MkI : kein Aufnahme
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- Jungspund
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GELÖST - STUDER B67 MkI : kein Aufnahme
Hello there,
Sorry for writing in english but I don't really master Deutsch.
A friend asked me to overhaul his Studer B67, which I did : all electrolytic and tantalum capacitors have been replaced on all of the audio boards, stabilizer and oscillator boards.
On the Tape Transport Control Board 1.67.761 I also had to replace one of the spooling motors control ICs (one TCA561 was dead, and it costs a fortune).
After the base revision was completed I started the calibration process as per the Service Manual : demagnetization, playback head azimuth, output levels, frequency response etc. And then I wanted to start the record amplifiers calibration but, and it is a big BUT, the machine doesn't record anything on tape !
Of course I first suspected something wrong in the record amplifiers, so I swapped them with my own B67 record amplifiers, to no avail.
I also checked voltage at pin J3-10 (Y-REC) on board 1.67.761 to find that when RECORD function is engaged by pressing RECORD and PLAY keys together, it drops from 12V to 0V. So I assume that Q12 base conduction is activated by IC1 (SC10429), concluding that it is alive and working. When machine is running in recording mode, tape is normally erased and the oscillator frequency is exactly 150KHz, so there are no issues there. All other functions are working normally.
This B67 has no VU-meters nor control panel. Of course I verified correct jumpers position on interconnection board, and I also visualized with the oscilloscope and 1KHz generator that input sinusoidal waveform arrives intact on the record amplifiers inputs.
Now I'm lost and I don't know where to look for fault, could someone put me on right tracks please ? I am running out of ideas...
Thanks for your help !
Thierry
Sorry for writing in english but I don't really master Deutsch.
A friend asked me to overhaul his Studer B67, which I did : all electrolytic and tantalum capacitors have been replaced on all of the audio boards, stabilizer and oscillator boards.
On the Tape Transport Control Board 1.67.761 I also had to replace one of the spooling motors control ICs (one TCA561 was dead, and it costs a fortune).
After the base revision was completed I started the calibration process as per the Service Manual : demagnetization, playback head azimuth, output levels, frequency response etc. And then I wanted to start the record amplifiers calibration but, and it is a big BUT, the machine doesn't record anything on tape !
Of course I first suspected something wrong in the record amplifiers, so I swapped them with my own B67 record amplifiers, to no avail.
I also checked voltage at pin J3-10 (Y-REC) on board 1.67.761 to find that when RECORD function is engaged by pressing RECORD and PLAY keys together, it drops from 12V to 0V. So I assume that Q12 base conduction is activated by IC1 (SC10429), concluding that it is alive and working. When machine is running in recording mode, tape is normally erased and the oscillator frequency is exactly 150KHz, so there are no issues there. All other functions are working normally.
This B67 has no VU-meters nor control panel. Of course I verified correct jumpers position on interconnection board, and I also visualized with the oscilloscope and 1KHz generator that input sinusoidal waveform arrives intact on the record amplifiers inputs.
Now I'm lost and I don't know where to look for fault, could someone put me on right tracks please ? I am running out of ideas...
Thanks for your help !
Thierry
Zuletzt geändert von Thierry am Samstag 9. Juli 2016, 22:33, insgesamt 1-mal geändert.
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- Trippel As
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Re: STUDER B67 MkI : kein Aufnahme
Hello Thierry
Welcome in the Revox and Studer forum....oder so ähnlich
Warmly
Clemens
Welcome in the Revox and Studer forum....oder so ähnlich
Warmly
Clemens
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Re: STUDER B67 MkI : kein Aufnahme
Hi Thierry,
I have no B67 myself, but isn't there an enable switch ???
on the later Studers you have to switch from save to ready
this enables the record mode
look after this and check how that works on your machine
best regards
Ralf
I have no B67 myself, but isn't there an enable switch ???
on the later Studers you have to switch from save to ready
this enables the record mode
look after this and check how that works on your machine
best regards
Ralf
Tonbandspulen ohne "wow & flutter"
Tonbandspulen mit gerfrästem ALU-Kern
Tonbandspulen mit gerfrästem ALU-Kern
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- Jungspund
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Re: STUDER B67 MkI : kein Aufnahme
Hi Ralf
Thanks for the suggestion but it's a "no Vu_meter" B67, hence no ready/safe switch.
Regards
Thierry
Thanks for the suggestion but it's a "no Vu_meter" B67, hence no ready/safe switch.
Regards
Thierry
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Re: STUDER B67 MkI : kein Aufnahme
hmm,
the A810 without VU have still a ready save switch
are you sure there is no "enable" Signal for ready, which has to be
switched or hard wired ???
sorry for haveing no better idea
Ralf
the A810 without VU have still a ready save switch
are you sure there is no "enable" Signal for ready, which has to be
switched or hard wired ???
sorry for haveing no better idea
Ralf
Tonbandspulen ohne "wow & flutter"
Tonbandspulen mit gerfrästem ALU-Kern
Tonbandspulen mit gerfrästem ALU-Kern
Re: STUDER B67 MkI : kein Aufnahme
Wenn der Bauteile tauschte, könnte er 'n Kondenser falsch rum verlötet haben oder so, falls das Luder vorher gelöscht haben sollte.
Wenner da noch nie inner Maschine gelötet und Erfahrungen hat, kommt er da nit weiter.
Da musser das Manual auf 'n Schoß nehmen und logisch bei der Fehlersuche vorgehen, oder das Luder jemanden bringen....
Wenner da noch nie inner Maschine gelötet und Erfahrungen hat, kommt er da nit weiter.
Da musser das Manual auf 'n Schoß nehmen und logisch bei der Fehlersuche vorgehen, oder das Luder jemanden bringen....
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- Jungspund
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Re: STUDER B67 MkI : kein Aufnahme
Hello,
Thanks to posters for trying to help.
To make things clear this is the B67 exact model I am working on :
As you can see there is no "Ready / Safe" switch, only the usual red RECORD pushbutton.
The jumpers on the Basis Board (1.67.700) are in positions I and L, as per the Service Manual :
@ cavemaen : all audio boards are perfectly working, after the revision I installed them into my own B67 and they work flawlessly, so the problem is definitely not a consequence of the overhaul.
This is my B67 : (https://lh3.googleusercontent.com/-esiU ... 030158.JPG)
Thierry
Thanks to posters for trying to help.
To make things clear this is the B67 exact model I am working on :
As you can see there is no "Ready / Safe" switch, only the usual red RECORD pushbutton.
The jumpers on the Basis Board (1.67.700) are in positions I and L, as per the Service Manual :
@ cavemaen : all audio boards are perfectly working, after the revision I installed them into my own B67 and they work flawlessly, so the problem is definitely not a consequence of the overhaul.
This is my B67 : (https://lh3.googleusercontent.com/-esiU ... 030158.JPG)
Thierry
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- Jungspund
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Re: STUDER B67 MkI : kein Aufnahme
Problem solved ! Issue was down to some bad (corroded) solder joints on the Basis PCB 1.167.700.
Special thanks to Ernst (Pievox) who guided me toward unexplored tracks so far. Always better to have an expert advise.
Thierry
Special thanks to Ernst (Pievox) who guided me toward unexplored tracks so far. Always better to have an expert advise.
Thierry