K5synth

It is very easy to find the inverter but it is not next to the
backlight.  It is a white box about 1.5"X.5"X1" in the right corner of
the K5 (as you are playing).  It is actually on the lid and it is next
to a bunch of blue capacitors.  

BE VERY VERY VERY CAREFUL because capacitors can be VERY dangerous.
(In some cases they can kill you!)

Make sure you unplug the K5 before doing anything.

You need to make sure the caps are discharged before you solder.  You
will have to take off three wire harness and take off six screws.  The
inverter has three solder points, and you need to resolder all three
points.  

AGAIN, you need to discharge the caps right after you take off the
power supply board.  It helps to test the voltage on the caps relative
to ground after you discharge them to make sure they are fully
discharged.  Caps have a way of getting "recharged" by their
neighbors. They should have 0V DC at both leads before you start doing
any solder work. 

I hate to be so paranoid but if you are not comfortable discharging
the caps DO NOT DO THIS REPAIR YOURSELF. It is just not worth getting
hurt just to have a backlight... (I think these all these caps charge
at a low voltage and should not be that dangerous, but without a
schematic I am just not certain and it is much better to be safe than
sorry on these things.)

Anyway, I did the resolder about 3 hours ago and so far things work
great.  I tried to remove as much of the old solder as I could, then I
applied globs of new solder.  It is nice to use my K5 in low light!

Good luck and be safe.


--- In k5synth@yahoogroups.com, "Cindy and Nathan" <Cthane1@a...> wrote:
> Good information.  My Nightlaunch backlight is still going strong on
my other gear, and I suppose I should get one for my K5.  First I will
try the re-solder thing since the Kawai tech support guy told me the
same thing.  Can I find the inverter easily?  Is is connected directly
to the backlight?   
> Didobrain
>   ----- Original Message ----- 
>   From: nelsonj_sce 
>   To: k5synth@yahoogroups.com 
>   Sent: Tuesday, September 14, 2004 11:57 PM
>   Subject: [k5synth] Re: New Backlight - inverter problems
> 
> 
>   Update:
>   Well today I ordered a new inverter from www.DigiKey.com.  I found an
>   inverter that looks like it will do the job - for those interested
it is:
> 
>   Digikey part #      289-1032-ND  and it only cost $11.90 - not bad.
> 
>   I am not sure if it will fit exactly in the same slots as the original
>   inverter so it might require some additional wiring.
> 
>   Anyway, I had my K5 open to look at the power supply to plan the new
>   inverter install when my K5 started "humming", and guess what, I now
>   have a beautiful blue backlight.  It looks great, a very cool blue. 
>   So it appears my inverter was not bad, but it just has bad solder
>   joints.  It is working for now but tomorrow I will likely take out the
>   board and redo all the solder joints.  
> 
>   Just some additional info I learned in researching backlights and
>   inverters.  The "brightness" of the backlight is a function of the
>   voltage and frequency applied to the backlight.  It appears one has a
>   lot of flexibility in selecting the inverter output voltage and freq.
>   For example, nightlauch says you can "test" the backlight by plugging
>   it directly in to a wall socket (120V AC @ 60 Hz here in the US)!  The
>   higher the voltage and freq the brighter the backlight.   However, the
>   backlight will "burn out" quicker the higher the freq.  So there is a
>   trade off, high freq = bright but shorter life.  
> 
>   Right now my stock inverter is putting out about 102V @ 380 Hz.  I
>   think the inverter I ordered will put out about 95V @ 540 Hz and
>   should work with a 3 - 6 V DC input.
> 
>   Next step, 147k resistors (also ordered from Digikey today).  
> 
> 
> 
>   --- In k5synth@yahoogroups.com, "nelsonj_sce" <nelsonj_sce@y...>
wrote:
>   > Well I replaced my backlight with one I ordered from
>   www.nightlaunch.com.
>   > 
>   > It took less than two weeks from when I ordered and the parts look
>   good.  
>   > 
>   > Good news/bad news though on my backlight.  
>   > 
>   > The good news:  I had no problems removing the LCD, taking out
the old
>   > backlight and sliding in the new backlight.  The new light has some
>   > wires and a plastic "tab" that kind of gets in the way, so I
soldered
>   > the backlight wires to where the wires connect to the LCD board. 
>   > Hint:You have to cut the new backlight to size, so make the
backlight
>   > a little longer (say 1/4 inch) than the original to make things
easier.
>   > 
>   > Bad news: My backlight does not work but I think my inverter is the
>   > problem.  I am only getting about 1/2 Volt at the output of my
>   > inverter, and I am supposed to get 120V @400Hz if I understand the
>   > part correctly.  I tested my inverter before I did the backlight
>   > install and saw it had low voltage, but I was hoping that my
existing
>   > "dead" backlight was causing the problem (i.e. it was shorted.) I
>   > guess not because even with the new backlight I get very low
voltage.
>   > 
>   > Anyway, it looks like I need to get an inverter.  I can get an
>   > inverter from nightlaunch for $17.99+s/h but it needs 9V DC.  I
>   > understand the inverter in the K5 uses 5V DC. 
>   >  
>   > Q1: Does the K5 inverter use 5V DC?
>   > Q2: If I measure the voltage on the two wires to the left of the
>   > inverter, should I get 120V if everything is working? (My Fluke says
>   > it is good <=1kHz)
>   > Q2: Does anyone know where to get a compatible K5 inverter and how
>   > much it will cost?
>   > 
>   > Thanks again for all the help.  This group is great.
> 
> 
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