K5synth

Hi, my name is Nicolas, i´m from Argentina and
i own a Kawai K5 synthesizer. The unit has been
working perfectly for the last 15 years, but today i
couldn´t turn it on. I opened the unit and checked all
the fuses and they were fine. Then i checked the
transformer and it was recieving current but when i
checked the regulators on the front panel none of them
had V on their outputs. I don`t want to mess around
with it unless im sure what im doing.
I´d be grateful if someone could provide me the
schematics, so i could repair the unit, its far too
expensive for me to send it back for tech support. Any help would be
welcome.
Thanx a lot.
Nicolas

Check if the tranformer outputs are normal (I assume about 18V 
alternating current RMS - about 40 volts peak-to-peak). Then check if  
there is stable DC voltage at the input of the voltage regulator 
chips. It should be about 15 to 20 volts with only about 100 
millivolts ripple on it.  There may be several regulator chips; one 
for each voltage like +5V, +12 and -12 volts are the most common.  If 
there is no output voltage on the output pin of any of the regulator 
chips, I would guess that something is shorting the voltage to ground. 
If you shake the box, does anything rattle?  It may be a piece of 
metal.  Is the transformer hot? There may be a short inside it.  Is 
there a lot of ripple voltage on the DC output after the transformer 
but before the voltage regulator chips?  Test the diodes or bridge 
rectifier.  Maybe the big filter capacitor has gone bad.


  Usually the actually electronic sound generator chips are last to go 
bad.  Usually the main power supply is the first component set to 
fail.


 




--- In k5synth@yahoogroups.com, "tuff_gnarl_69" <tuff_gnarl_69@y...> 
wrote:

> Hi, my name is Nicolas, i´m from Argentina and


> i own a Kawai K5 synthesizer. The unit has been


> working perfectly for the last 15 years, but today i


> couldn´t turn it on. I opened the unit and checked all


> the fuses and they were fine. Then i checked the


> transformer and it was recieving current but when i


> checked the regulators on the front panel none of them


> had V on their outputs. I don`t want to mess around


> with it unless im sure what im doing.


> I´d be grateful if someone could provide me the


> schematics, so i could repair the unit, its far too


> expensive for me to send it back for tech support. Any help would be


> welcome.


> Thanx a lot.


> Nicolas

Is there power coming out of the bridge ?

(If you want schemes, ask to kjtkfuenf , so, developer@...)

Antoine

"tuff_gnarl_69" <tuff_gnarl_69@...> wrote:

>Hi, my name is Nicolas, i\ufffdm from Argentina and
>i own a Kawai K5 synthesizer. The unit has been
>working perfectly for the last 15 years, but today i
>couldn\ufffdt turn it on. I opened the unit and checked all
>the fuses and they were fine. Then i checked the
>transformer and it was recieving current but when i
>checked the regulators on the front panel none of them
>had V on their outputs. I don`t want to mess around
>with it unless im sure what im doing.
>I\ufffdd be grateful if someone could provide me the
>schematics, so i could repair the unit, its far too
>expensive for me to send it back for tech support. Any help would be
>welcome.
>Thanx a lot.
>Nicolas
>
>
>



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I don't know the insides of this beast yet, but I'd check  for the 
usual dry joints, any signs of even the minutest circuit board 
cracking/stress around switches or anything heavy like big capacitors 
on the board. Check the regs one at a time, most shut down if there's 
a real problem, but they can just fail and not do anything. If 
anything's getting hot that shouldn't power down and get a circuit 
schematic.

Look around the main switch on the kb too, it may just have become 
dry jointed because of all that pushing on and off over the years...

hope you fix it

Adam

--- In k5synth@yahoogroups.com, antdes45@n... wrote:
> Is there power coming out of the bridge ?
> 
> (If you want schemes, ask to kjtkfuenf , so, developer@k...)
> 
> Antoine
> 
> "tuff_gnarl_69" <tuff_gnarl_69@y...> wrote:
> 
> >Hi, my name is Nicolas, i´m from Argentina and
> >i own a Kawai K5 synthesizer. The unit has been
> >working perfectly for the last 15 years, but today i
> >couldn´t turn it on. I opened the unit and checked all
> >the fuses and they were fine. Then i checked the
> >transformer and it was recieving current but when i
> >checked the regulators on the front panel none of them
> >had V on their outputs. I don`t want to mess around
> >with it unless im sure what im doing.
> >I´d be grateful if someone could provide me the
> >schematics, so i could repair the unit, its far too
> >expensive for me to send it back for tech support. Any help would 
be
> >welcome.
> >Thanx a lot.
> >Nicolas
> >
> >
> >
> 
> 
> 
> __________________________________________________________________
> Switch to Netscape Internet Service.
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Caps shouldn't be a problem, they're ELNAs that instead of leaking are sealing the cracks with a battery acid blue kind thing.

The only problem I got with it: 
Bad working switches and keys,
dry joints and
broken power switch wire(My K5 died while I was playing).

If the regulators or DACs(BB PCM55HP) are getting really(regs) hot(both) after a while(dacs is when playing), this is normal. If you have a microphone used for recording near and having no backlight don't bother you, just remove the inverter.

"Adam Moss" <g0ory@...> wrote:

>I don't know the insides of this beast yet, but I'd check  for the
>usual dry joints, any signs of even the minutest circuit board
>cracking/stress around switches or anything heavy like big capacitors
>on the board. Check the regs one at a time, most shut down if there's
>a real problem, but they can just fail and not do anything. If
>anything's getting hot that shouldn't power down and get a circuit
>schematic.
>
>Look around the main switch on the kb too, it may just have become
>dry jointed because of all that pushing on and off over the years...
>
>hope you fix it
>
>Adam
>
>--- In k5synth@yahoogroups.com, antdes45@n... wrote:
>> Is there power coming out of the bridge ?
>>
>> (If you want schemes, ask to kjtkfuenf , so, developer@k...)
>>
>> Antoine
>>
>> "tuff_gnarl_69" <tuff_gnarl_69@y...> wrote:
>>
>> >Hi, my name is Nicolas, i\ufffdm from Argentina and
>> >i own a Kawai K5 synthesizer. The unit has been
>> >working perfectly for the last 15 years, but today i
>> >couldn\ufffdt turn it on. I opened the unit and checked all
>> >the fuses and they were fine. Then i checked the
>> >transformer and it was recieving current but when i
>> >checked the regulators on the front panel none of them
>> >had V on their outputs. I don`t want to mess around
>> >with it unless im sure what im doing.
>> >I\ufffdd be grateful if someone could provide me the
>> >schematics, so i could repair the unit, its far too
>> >expensive for me to send it back for tech support. Any help would
>be
>> >welcome.
>> >Thanx a lot.
>> >Nicolas
>> >
>> >
>> >
>>
>>
>>
>> __________________________________________________________________
>> Switch to Netscape Internet Service.
>> As low as $9.95 a month -- Sign up today at
>http://isp.netscape.com/register
>>
>> Netscape. Just the Net You Need.
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>> New! Netscape Toolbar for Internet Explorer
>> Search from anywhere on the Web and block those annoying pop-ups.
>> Download now at http://channels.netscape.com/ns/search/install.jsp
>
>


-- 
Antoine Desch\ufffdnes
aka DragonMaster
http://thehotcom.deep-ice.com/
Files:http://angelfire.com/ca7/hotcomcenter/


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Sure Antoine, I couldn't see the power supply properly in the K5m 
photo's on the group, perhaps the K5 and K5m power supply board are 
the same? ;-)

> The only problem I got with it: 
> Bad working switches and keys,
> dry joints and
> broken power switch wire(My K5 died while I was playing).

Good basic 'age' faults for equipment of that age, I'm glad they're 
the only problems. 

Something that worked for so long, and then just stopped is going to 
be a easy fix (I hope) once the fault is found.

cheers, Antoine

Adam

The PSU is really simple: has 3 fuses, 2 bridges, 3(4 on diff country) regulators, a couple of caps and an inverter.

The K5 and K5m are basically the same things except for interface changes(Diff. BIOS) and that there's no keyboard.

Antoine

"Adam Moss" <g0ory@...> wrote:

>Sure Antoine, I couldn't see the power supply properly in the K5m 
>photo's on the group, perhaps the K5 and K5m power supply board are 
>the same? ;-)
>
>> The only problem I got with it: 
>> Bad working switches and keys,
>> dry joints and
>> broken power switch wire(My K5 died while I was playing).
>
>Good basic 'age' faults for equipment of that age, I'm glad they're 
>the only problems. 
>
>Something that worked for so long, and then just stopped is going to 
>be a easy fix (I hope) once the fault is found.
>
>cheers, Antoine
>
>Adam
>
>
>


-- 
Antoine Desch\ufffdnes
aka DragonMaster
http://thehotcom.deep-ice.com/
Files:http://angelfire.com/ca7/hotcomcenter/


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