Vintage Synth Repair

Apologies if this has been posted before, I came across it while  
searching for a manual.  It's quite a lot of synth service manuals in  
PDF format!

http://manuals.fdiskc.com/flat/

Regards,
Lindsay

H everyone,
Sorry I´ve been so quiet lately. I´ve been buried in work, writing, 
recording and doing service.
I have just finished service on a Roland VP-330 vocoder/human 
voice/string keyboard, Mark 1, the one with the rocker switches.
Very good machine! But a torture to service and adjust. The schematics 
specify cheap op-amps (4558), but - at the time - state-of-the-art 
op-amps for the final outputs of each board (TL082). However, these 
specified TL082s were not used, it seems, at least not on this stock 
model. They used LM353s all the way, and several of these had failed, 
so that the string was dead, and some of the vocoder filters were not 
working because the op-amps have gone into self-occilation. So after 
debugging and swapping out defected parts, it was down to adjustments. 
For at start, the vocoder sounded dull and unfocused, but somewhat 
right. But the carrier signal was bleeding through a lot. Who would 
have thought that this was among the "best vocoders ever", even used by 
Krafwerk at some point in their carrier?
Well, the vocoder card, with the 10band filters, VCAs and corresponding 
"companders" (compressors + expanders) is neatly laid out, but fiddly 
to adjust. As usual with analog, everything influences each other, so 
there was a roundabout of going back and forth on all the trimmers. I 
feared I would bump into one extreme of any trimmer, so that I would 
have to change resistors as well in order to tune the circuts, but it 
all held together.
After hours of work, I must say that the sonic that this machine now 
creates is amazing. Very distinct vocoder with good sound, the the 
combined human voice and string is indeed very charming.
The machine is full of Roland chips (BA662s etc.), and not to mention 
all the SAD chips for the chorus, so if anything major starts failing 
it will be a nightmare.
But as long as those chips hold, this is a dream machine. And now that 
I have done one and learned it´s secrets, I am sure the next one will 
be a breeze.
Remember to use the right service manual; mark I is significantly 
different from Mk. 2.
Also remember to be patient: every time you adjust a vocoder filter, it 
takes some time to stabilize, so be cool  :-)


Terje Winther
terje.winther@...
http://www.wintherstormer.no/

The differences between Mk 1 and 2 are, as I understand it:
- different power
- different keyboard
- different switches on front panel
- different vocoder board
- different string/human voice card
- different chorus chips (SAD vs. MN3xxx)
There also seems to be a "transition model", where they used the old 
board with "add-ons". Probably a short series of numbers.
I recall seeing a leaflet that lists all the changes in respect to the 
serial numbers.

tw.


På 22. feb. 2009 kl. 22.01 skrev Philip:

> How different is it to the MK2? I serviced one and found it a very 
> easy synth to calibrate.
>  
> Thanks, Phil.
>
> --- On Sun, 22/2/09, Terje Winther <terje.winther@...> 
> wrote:
>> From: Terje Winther <terje.winther@wintherstormer.no>
>> Subject: [vintagesynthrepair] Adjusting VP-330 Mk.1
>> To: vintagesynthrepair@yahoogroups.com
>> Date: Sunday, 22 February, 2009, 8:21 PM
>>
>> H everyone,
>> Sorry I´ve been so quiet lately. I´ve been buried in work, writing,
>> recording and doing service.
>> I have just finished service on a Roland VP-330 vocoder/human
>> voice/string keyboard, Mark 1, the one with the rocker switches.
>> Very good machine! But a torture to service and adjust. The schematics
>> specify cheap op-amps (4558), but - at the time - state-of-the- art
>> op-amps for the final outputs of each board (TL082). However, these
>> specified TL082s were not used, it seems, at least not on this stock
>> model. They used LM353s all the way, and several of these had failed,
>> so that the string was dead, and some of the vocoder filters were not
>> working because the op-amps have gone into self-occilation. So after
>> debugging and swapping out defected parts, it was down to adjustments.
>> For at start, the vocoder sounded dull and unfocused, but somewhat
>> right. But the carrier signal was bleeding  through a lot. Who would
>> have thought that this was among the "best vocoders ever", even used 
>> by
>> Krafwerk at some point in their carrier?
>> Well, the vocoder card, with the 10band filters, VCAs and 
>> corresponding
>> "companders" (compressors + expanders) is neatly laid out, but fiddly
>> to adjust. As usual with analog, everything influences each other, so
>> there was a roundabout of going back and forth on all the trimmers. I
>> feared I would bump into one extreme of any trimmer, so that I would
>> have to change resistors as well in order to tune the circuts, but it
>> all held together.
>> After hours of work, I must say that the sonic that this machine now
>> creates is amazing. Very distinct vocoder with good sound, the the
>> combined human voice and string is indeed very charming.
>> The machine is full of Roland chips (BA662s etc.), and not to mention
>> all the SAD chips for the chorus, so if anything major starts failing
>> it will be a nightmare.
>> But as long as those chips hold, this is a dream machine. And now that
>> I have done one and learned it´s secrets, I am sure the next one will
>> be a breeze.
>> Remember to use the right service manual; mark I is significantly
>> different from Mk. 2.
>> Also remember to be patient: every time you adjust a vocoder filter, 
>> it
>> takes some time to stabilize, so be cool :-)
>>
>> Terje Winther
>> terje.winther@ wintherstormer. no
>> http://www.winthers tormer.no/
>>
>
> 
>
tw.  :)

"Those great moments come when musicians are playing together..."
(Bob Moog)