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2010-05-20 by alexandrodeexu
Hi I have a problem with Roland SH101,after exchange of pots in VCF and Envelop to brand new,all envelop generator settings became wrong,maximum time for Attac,Decay & Realise is about 1.5s ( must be 10s ),And also there's no effect from sustain pot if I stay high decay parameter. Thanx.
2010-05-20 by duncan
>>I have a problem with Roland SH101,after exchange of pots in VCF and Envelop to brand new,all envelop generator settings became wrong,maximum time for Attac,Decay & Realise is about 1.5s ( must be 10s ),And also there's no effect from sustain pot if I stay high decay parameter.<< well, the obvious question is: are the new pots /definitely/ the same value as the old ones? because even if you replaced the pots with a different law (e.g. swapped linear for logarithmic, or "A" curve for "B" as it's probably marked on them), you would still get the same maximum value at the top end of the adjustment. try this- replace the release pot with three wires & hook the other ends to a 250k or 500k pot (anything will do), then measure the resistance of this pot when you adjust it to achieve your required release time. there are other components that contribute to generating these time constants, but you don't mention changing any capacitors. have you got the schematics to look at? I have only an MC202 here, but I'd reckon it has the same design of ADSR. I'll see if I can find the drawing & have a look. duncan.
2010-05-21 by Brian
For what it's worth I too would suspect the new pots are not the correct value. From your description I would hazard a guess that the new pots are out by a factor of 10; so for example if the original pot had a value of 1M Ohm the new pot was 100k Ohms. This would account for the reduction of around 10 in your decay time. I'd check the old pots against the new using a multimeter. Regards Brian G3OYU
From: vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of alexandrodeexu Sent: 20 May 2010 5:13 To: vintagesynthrepair@yahoogroups.com Subject: [vintagesynthrepair] Roland SH101 envelop generator Hi I have a problem with Roland SH101,after exchange of pots in VCF and Envelop to brand new,all envelop generator settings became wrong,maximum time for Attac,Decay & Realise is about 1.5s ( must be 10s ),And also there's no effect from sustain pot if I stay high decay parameter. Thanx.
2010-05-21 by alexandrodeexu
Thanx,Brian But I have all circuit diagrams for SH101 and all pots i've replaced are with right nominal ( 1MOhm for ADR ) we offered this set - http://www.technologytransplant.com/product_info.php?cPath=30_29_4&products_id=57 --- In vintagesynthrepair@yahoogroups.com, "Brian" <brian@...> wrote:
> > For what it's worth I too would suspect the new pots are not the correct > value. From your description I would hazard a guess that the new pots are > out by a factor of 10; so for example if the original pot had a value of 1M > Ohm the new pot was 100k Ohms. This would account for the reduction of > around 10 in your decay time. > > > > I'd check the old pots against the new using a multimeter. > > > > Regards > > Brian G3OYU > > > > From: vintagesynthrepair@yahoogroups.com > [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of alexandrodeexu > Sent: 20 May 2010 5:13 > To: vintagesynthrepair@yahoogroups.com > Subject: [vintagesynthrepair] Roland SH101 envelop generator > > > > > > Hi > I have a problem with Roland SH101,after exchange of pots in VCF and Envelop > to brand new,all envelop generator settings became wrong,maximum time for > Attac,Decay & Realise is about 1.5s ( must be 10s ),And also there's no > effect from sustain pot if I stay high decay parameter. > Thanx. >
2010-05-21 by alexandrodeexu
Thanx,Dunkan all pots I replaced for the same value,I have circuit diagrams I tried to disconect Realeas pot ,the time of realise was about 10s --- In vintagesynthrepair@yahoogroups.com, "duncan" <ferrograph@...> wrote:
> > >>I have a problem with Roland SH101,after exchange of pots in VCF and Envelop to brand new,all envelop generator settings became wrong,maximum time for Attac,Decay & Realise is about 1.5s ( must be 10s ),And also there's no effect from sustain pot if I stay high decay parameter.<< > > well, the obvious question is: are the new pots /definitely/ the same value as the old ones? because even if you replaced the pots with a different law (e.g. swapped linear for logarithmic, or "A" curve for "B" as it's probably marked on them), you would still get the same maximum value at the top end of the adjustment. > > try this- replace the release pot with three wires & hook the other ends to a 250k or 500k pot (anything will do), then measure the resistance of this pot when you adjust it to achieve your required release time. > there are other components that contribute to generating these time constants, but you don't mention changing any capacitors. have you got the schematics to look at? I have only an MC202 here, but I'd reckon it has the same design of ADSR. I'll see if I can find the drawing & have a look. > > duncan. >
2010-05-26 by duncan
>>all pots I replaced for the same value,I have circuit diagrams > I tried to disconect Realeas pot ,the time of realise was about 10s<< the only other thing I can think of is that there are some timing capacitors around the envelope generator that have changed their values with age. was the ADSR working properly before you changed the pots? d.