Vintage Synth Repair

I have put the DR-55 service manual on my Downloads page at
www.paintingwithsound.co.nz.

--- In vintagesynthrepair@yahoogroups.com, freckles <freckles@...> wrote:
>
> Hi Scott
> 
> thanks for your info, and sorry for the HUGE delay in getting back
to this.
> 
> Its not a start-button problem. regardless of what is programmed in the 
> memory, when the cpu [tc5501] sends out the drum trigger signals, its 
> like each trigger is doubled. its not a semi-quaver apart but maybe
10ms 
> or something, which makes me wonder if the sounds are restarting on the 
> falling edge of the trigger pulse as well? but maybe its more basic
than 
> that..
> 
> my knowlege of electronics is very limited - i don't even understand 
> what's happening in the clock circuit, maybe the problem is there as it 
> connects directly to one of the cpu pins next to the trigger
outputs.. ? 
> what would happen if C42 was faulty? What does NP 1/50 mean [next to 
> C42]. I tried replacing the 4011UB but no change.
> 
> Any help very much appreciated
> 
> Thanks
> 
> Chris
> 
> Scott Nordlund wrote:
> > I don't have a DR-55 but I downloaded the service manual for my own 
> > amusement (I'm cool like that).  I would guess that the note
button is 
> > double-triggering, and the sequencer then correctly plays back the 
> > wrongly-entered sequences (where you can turn the tempo down and hear 
> > two successive steps rather than a double-triggered flam), yes?  If 
> > I'm understanding this correctly, the rest button shouldn't 
> > double-trigger, and you should replace C45.
> >
> >    
------------------------------------------------------------------------
> >     To: vintagesynthrepair@yahoogroups.com
> >     From: freckles@...
> >     Date: Thu, 10 Apr 2008 18:10:14 +0000
> >     Subject: [vintagesynthrepair] Boss DR-55 sounding problem
> >
> >     Hi just wondering if anyone has some advice/tips for me.
> >
> >     I have what appears to be a fully working DR-55 except the
drum sounds
> >     are double-triggering. most noticeable is the kick which obviously
> >     flams, making it sound very farty.
> >
> >     I don't have a scope but i've recorded it to my laptop and can
see the
> >     double peak.
> >
> >     Anyone have any idea what it could be? I can mail relevant service
> >     manual pages if that helps.
> >
> >     Thanks
> >
> >
> >
> >
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