Korg Poly800/EX800 Users

Hi ive just bought a broken poly 800, my intention was to fix it and 
convert it so i can have it rack mounted.
Unforunatly it has nothing on the display but when i switch it on i 
can hear power.
Ive taken it apart and with my basic knowledge tried to fix it but 
now realise i have two choices.
Sell it to an electronics expert or buy another faulty one and 
hopefully use parts from both to make a good un.
So my question: does anyone here (from the UK) have a faulty one to 
sell or know where i could get it cheaply repaired.
thanks

Greetings
 
I've repaired several of these machines....the GROUP Korgpolyex has tons of past
forum discussions about the usual ailment with these.....most often just the internal
3 volt Lithium Battery on the main PCB is dead, losing all its presets......so there is
nothing in recent memory to work with, thus it appears dead, but in all probability you
just re-program into "11" any voice parameters that produces more than noise......
then save this to a differnet patch#, and then youll know if its worth while to proceed....
If that works, then install a new battery onto the circuit board and program the remainder
of the patches......check out the files area of this group , as well
Cheers,
Dan
Dannobe123@...

Hi
Thanks for the info i did have a problem with my old poly with he 
battery and that is now fixed but my other one has nothing on the 
display but i can hear a very faint power hum when i switch it on.. 
just the sound of the power going through the circuits.
I have pressed the keys and nothing happens :(
Maybe this poly with no display is gonna be difficult to fix?


--- In korgpolyex@yahoogroups.com, Dan Brewton <dannobe123@y...> 
wrote:
> Greetings
>  
> I've repaired several of these machines....the GROUP Korgpolyex 
has tons of past
> forum discussions about the usual ailment with these.....most 
often just the internal
> 3 volt Lithium Battery on the main PCB is dead, losing all its 
presets......so there is
> nothing in recent memory to work with, thus it appears dead, but 
in all probability you
> just re-program into "11" any voice parameters that produces more 
than noise......
> then save this to a differnet patch#, and then youll know if its 
worth while to proceed....
> If that works, then install a new battery onto the circuit board 
and program the remainder
> of the patches......check out the files area of this group , as 
well

> Cheers,
> Dan
> Dannobe123@y...

Hi......... The next highest Probability, to me, is the Power Supply within the Unit....
These do fail occasionally.....Internally there is both a +5 volt and -5 volt regulated
supply system ,derived from the 12DC volts input externally......sometimes people get lazy and plug most anything into the jack, and , wallah, its toast.......but one saving grace is this one dies without allowing massive over-voltage to the sensitive logic circuits that need no more than 5 volts.....usually......cant know for sure until the supply is fixed, then you get to discover if the 'next layer' survived......These Power supplies are a bit difficult to repair... known as "switchers" .....pretty tricky......some guys I know just gut it out and
replace with external supply, regulated +/- 5 volts.......naturally you need the schematics
for all this....... let me know !
Cheers
Dan

Hi Dan
Thanks for the info thats very interesting.
I know the external supply is ok because i use it with my working 
poly 800. Im now thinking about checking the internal power supply 
and am quite handy with a soldering iron. Do you know what i should 
test or replace, i have downloaded the schematics but dont know the 
best place to begin.
Regards
Neil

--- In korgpolyex@yahoogroups.com, Dan Brewton <dannobe123@y...> 
wrote:
> Hi......... The next highest Probability, to me, is the Power 
Supply within the Unit....
> These do fail occasionally.....Internally there is both a +5 volt 
and -5 volt regulated
> supply system ,derived from the 12DC volts input 
externally......sometimes people get lazy and plug most anything 
into the jack, and , wallah, its toast.......but one saving grace is 
this one dies without allowing massive over-voltage to the sensitive 
logic circuits that need no more than 5 volts.....usually......cant 
know for sure until the supply is fixed, then you get to discover if 
the 'next layer' survived......These Power supplies are a bit 
difficult to repair... known as "switchers" .....pretty 
tricky......some guys I know just gut it out and
> replace with external supply, regulated +/- 5 
volts.......naturally you need the schematics

> for all this....... let me know !
> Cheers
> Dan