Vintage Synth Repair

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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