Vintage Synth Repair

Oops, how right you are!

I can't hear any flam on the hi-hat, its quite a soft attack on it 
anyway so I might not hear if it was. In the "8" mode the hi-hat lags 
behind by what sounds like a constant amount. At faster tempos it sounds 
ridiculously out of time! Maybe all dr-55s do that - I don't know...

A scope would be better but I suppose I could connect J2 to my 
soundcard, record it and look at the wave. might be wise to go through a 
DI box or something though, don't wanna blow my inputs.


Chris


Scott Nordlund wrote:
> There actually isn't a CPU- the TC5501 is a RAM chip (interesting design!).  
>
> I think this would be a very easy problem to solve with an oscilloscope, but things get a little more "interesting" if you don't have one.
>
> Do you hear the "flam" sound on the hi-hat sound?  Do the "16" and "8" modes work properly (8 should be half-speed)?  Do they both have the "flam" sound? 
>
> Do you have a way of observing what comes out of J2?
>
> C42 should determine the tempo, so it's probably fine.
>
> ________________________________
> To: vintagesynthrepair@yahoogroups.com
> From: freckles@...
> Date: Sun, 12 Oct 2008 17:23:59 +0100
> Subject: Re: [vintagesynthrepair] Boss DR-55 sounding problem - FINALLY!
>
> 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.
>>     
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>   
>
>   
>> I don't have a scope but i've recorded it to my laptop and can see the
>>     
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>   
>> double peak.
>>     
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>   
>
>   
>> Anyone have any idea what it could be? I can mail relevant service
>>     
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>   
>> manual pages if that helps.
>>     
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>   
>
>   
>> Thanks
>>     
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>   
>
>   
>
>   
>
>   
>> ----------------------------------------------------------
>>     
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>   
>> More immediate than e-mail? Get instant access with Windows Live
>>     
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>> Messenger.
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