Vintage Synth Repair

I don't have the service manual, but NP 1/50 probably means 1uF 50V non-polar.

2008/10/12 freckles <freckles@...>:
> 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@freeola.com
>>     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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>
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-- 
Antoine Deschênes