The Kawai & Teisco Analog Synths Group

Hi all,

My Roland MKS-70 suddently started to behave strange.
These are the synpthoms:

1. Most of the times (but not always), in addition to
the correct preset name and all other information, the
entire display lights up. You can see it all lights up
but while the actaul data lights a bit more strongly.

2. Many times it will display ok, but after a few
minutes of working with it, it will restart itself or
will just stop displaying anything (blank display) or
will just display only a portions of a few
charaters...

3. Once the problem initially occured, I tried to fix
it and than found that in addition to the problems
mentioned, the main CPU of one of the synth boards was
defected (played corrupt sounds). I replaced it and it
solve this specific problem but all other ramined...

5v and 15v rails seems to be ok (I measured 4.85v and
14.8v).

Does anyone have any idea what could that be and were
to look at ?

Thanks in advance !

4.85v seems a little low for the 5v rail. Something may be dragging it down. Here s a link to what I believe is the service manual.... 

Both volatges were measured while the PS is disconnected from the 
rest of the unit... What could cause them to be a little down ? There 
is no VR for voltage adjustment ... 


--- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> 
wrote:
> 4.85v seems a little low for the 5v rail. Something may be dragging 
it
> down. Here's a link to what I believe is the service manual....
> 
> http://www.synthzone.com/midi/roland/mks70/
> 
> 
> 
>   ----- Original Message -----
>   From: gil_we
>   To: kawai_sx210@yahoogroups.com
>   Subject: [kawai_sx210] MKS-70 problem
>   Date: Fri, 02 Sep 2005 13:00:57 -0000
> 
>   Hi all,
> 
>   My Roland MKS-70 suddently started to behave strange.
>   These are the synpthoms:
> 
>   1. Most of the times (but not always), in addition to
>   the correct preset name and all other information, the
>   entire display lights up. You can see it all lights up
>   but while the actaul data lights a bit more strongly.
> 
>   2. Many times it will display ok, but after a few
>   minutes of working with it, it will restart itself or
>   will just stop displaying anything (blank display) or
>   will just display only a portions of a few
>   charaters...
> 
>   3. Once the problem initially occured, I tried to fix
>   it and than found that in addition to the problems
>   mentioned, the main CPU of one of the synth boards was
>   defected (played corrupt sounds). I replaced it and it
>   solve this specific problem but all other ramined...
> 
>   5v and 15v rails seems to be ok (I measured 4.85v and
>   14.8v).
> 
>   Does anyone have any idea what could that be and were
>   to look at ?
> 
>   Thanks in advance !
> 
> 
> 
> 
> 
>   SPONSORED LINKS
>   Sampler Electronic instrument Synthesizer
>   Synthesizer music Electronic music Music sampler
> 
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It seems it is working ok now.

I found there was a bad contact somewhere as all the sympthoms 
mentioned occured also when rotating the unit, as I later found.

I found it was at the power supply unit, and I cleaned the board and 
resoldered it, so far it works ok.

I can also notice that the displayed characters now are much more 
bright, guess there was a voltage issue in there.

Rail volatges still show 4.8v and 14.8v btw...


--- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> 
wrote:
> 4.85v seems a little low for the 5v rail. Something may be dragging 
it
> down. Here's a link to what I believe is the service manual....
> 
> http://www.synthzone.com/midi/roland/mks70/
> 
> 
> 
>   ----- Original Message -----
>   From: gil_we
>   To: kawai_sx210@yahoogroups.com
>   Subject: [kawai_sx210] MKS-70 problem
>   Date: Fri, 02 Sep 2005 13:00:57 -0000
> 
>   Hi all,
> 
>   My Roland MKS-70 suddently started to behave strange.
>   These are the synpthoms:
> 
>   1. Most of the times (but not always), in addition to
>   the correct preset name and all other information, the
>   entire display lights up. You can see it all lights up
>   but while the actaul data lights a bit more strongly.
> 
>   2. Many times it will display ok, but after a few
>   minutes of working with it, it will restart itself or
>   will just stop displaying anything (blank display) or
>   will just display only a portions of a few
>   charaters...
> 
>   3. Once the problem initially occured, I tried to fix
>   it and than found that in addition to the problems
>   mentioned, the main CPU of one of the synth boards was
>   defected (played corrupt sounds). I replaced it and it
>   solve this specific problem but all other ramined...
> 
>   5v and 15v rails seems to be ok (I measured 4.85v and
>   14.8v).
> 
>   Does anyone have any idea what could that be and were
>   to look at ?
> 
>   Thanks in advance !
> 
> 
> 
> 
> 
>   SPONSORED LINKS
>   Sampler Electronic instrument Synthesizer
>   Synthesizer music Electronic music Music sampler
> 
>   ------------------------------------------------------------------
--
> 
>   YAHOO! GROUPS LINKS
> 
>     *  Visit your group "kawai_sx210" on the web.
> 
>     *  To unsubscribe from this group, send an email to:
>       kawai_sx210-unsubscribe@yahoogroups.com
> 
>     *  Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>       Service.
> 
> 
>   ------------------------------------------------------------------
--

> 
> -- 
> ___________________________________________________________
> Sign-up for Ads Free at Mail.com
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