Vintage Synth Repair

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)