Re: Re: K5 Repair Issues

Hi Bruce,

OK, so you're not attempting to replace the LCD but the backlight. The
inverter is only providing high voltage for the backlight. The actual LCD
works off the ribbon wire.

I guess I should explain things a bit :
The LCD and backlight are two separate things making the actual LCD module.
The LCD normally has a grey background and displays the pixels. Same thing
as a calculator. If you use a light and adjust the contrast knob properly,
you should see it well. Since the LCD is semi-transparent, it's possible to
have backlighting behind it, so you don't need any light. It's usually an EL
foil that works at 120V AC at 400Hz. The inverter is there to convert the
low voltage to the proper AC voltage and frequency used by the EL foil. The
LCD is powered by 5V and should be working forever unless the glass panel is
broken. But, the EL foils degrade over time, and this is what is happening
with the K5. The inverter isn't supposed to fail, but in the case of the K5,
it fails because there are poor solders joints inside of the inverter, which
is stuck in epoxy into a plastic case (can't be repaired, only replaced).

To connect the new backlight, there are two wires (green and violet) going
from the power supply board to the LCD. One wire connects to one of the
pins, and the other to another pin (Which wire goes where isn't important)
If the new backlight is an exact replacement, you should be able to unsolder
two pins from the old one and connect the new one at the same place.

RadioShack should have the solder make sure you specify rosin-core leaded
solder though. I think I wasn't clear, you don't need flux if you use rosin
core solder. The rosin is the flux, and it's inside the solder wire.

I'll try to take pictures, but I'm a bit stuck in time right now with lots
of projects and things to do. If you have already unscrewed the LCD module
from the cover once, you'll see it's probably easier than you think with the
information I provided you. The green and violet wires are connecting to two
traces on the LCD circuit board. If you follow them, you'll see the two pins
of the original backlight soldered right there.

One other thing, you talked about a soldering "gun" in the last mail. Is it
really a solder gun (high wattage, heavy tasks) or an iron (20-70 watts, has
a pointy tip)? How many watts is it? I have doubts because you asked about
the tip. About any soldering iron stock tip should work there, you're not
going to do a miniature solder job.

Antoine

2008/1/20, BJM <[email protected]>:
>
>  Antoine,
>
> I can read the LCD , so I am guessing the inverter is all right for now. I
> have the Telesis backlight already and was wondering if there is a diagram
> of the two pins that I would need to solder?
>
> Do you think they would have the solder and flux at Radio Shack?
>
> Are there are any good diagrams of this procedure that would be great.
>
> Thanks for your help so far.
>
> Bruce
>
>  ------------------------------
> *From:* [email protected] [mailto:[email protected]] *On
> Behalf Of *Antoine Deschênes
> *Sent:* Thursday, January 17, 2008 12:15 AM
> *To:* [email protected]
> *Subject:* Re: [k5synth] Re: K5 Repair Issues
>
>  Hi, the LCD shouldn't be failing unless there's a major problem.
>
> Only the backlight, which is replaceable, usually needs a replacement as
> well as the inverter. If you're able to read what's on the LCD display when
> the room is well lit or with a flashlight and you adjust the contrast button
> correctly, all it needs is a backlight replacement. (Only two pins to
> solder, not >16)
>
> To know when the inverter is failing, you have a few options :
> 1. Change the backlight first, if it doesn't work, change the inverter.
> 2. There's no whine noise coming from it.
> 3. Change it, it will fail anyways if it's the original one.
>
> Don't use lead-free solder in there, it's only going to cause problems
> with time (You can't mix both types, and the K5 was built with SnPb solder).
> You can use some Sn60/Pb40, Sn63/Pb37 or Sn60/Pb36/Ag4 type. Use solder with
> a rosin flux core, you will not have to use separate flux and you will not
> need to clean it off after.
>
> As for the iron tip, what's your soldering iron?
>
> Antoine
>
> 2008/1/16, BJM <[email protected]>:
> >
> >  Antoine,
> >
> > I bought the LCD from Telesis. I went through the directions that were
> > provided by CD from Telesis. The directions were general in nature (they
> > sell other brands of LCDs). I saw descrepancies from what was in the
> > documentation and actually in the K5*M*.
> >
> > I work with computers but I hesitate to move forward on the LCD when the
> > directions are not what I am seeing, especially when it requires soldering.
> >
> >
> >    - The size of the tip of the soldering gun and the type of solder
> >    recommendations are other questions I would have. I
> >    - How would I know if the inverter should be replaced?
> >    - Are there any diagrams of the installation?
> >
> > If someone has put in one of the Telesis LCDs in your K5*M*, your
> > experience would be appreciated.
> > My K5 *keyboard* has a good strong LCD, I suspect it may have been
> > replaced before I bought it.
> >
> > I am hearing of people programming the K5s by flashlight.A good strong
> > clipon music light on the rack, or on a rack ear, has helped.
> >
> > Hopefully I will replace the LCD, with your help.
> >
> > Thanks for listening.
> >
> > Bruce
> >
> >
> >
> >
> >
> >  ------------------------------
> > *From:* [email protected] [mailto:[email protected]] *On
> > Behalf Of *Antoine Deschênes
> > *Sent:* Wednesday, January 16, 2008 10:13 AM
> > *To:* [email protected]
> > *Subject:* Re: [k5synth] Re: K5 Repair Issues
> >
> >   Hi Bruce, it's hard to find two identical LCDs. We'd need more
> > information about the one you just bought to be able to give out more
> > details.
> >
> > Antoine
> >
> > BJM a écrit :
> > > i can empathize with the disappointment of the LCD installation. I
> > > picked up a new LCD for my K5M and have been hesitant to install it
> > > due to some of those "unknowns" that might come up. If any diagrams,
> > > sequential steps, associated problems of the installation were
> > > identified for the group and posted that would be great. It seems like
> >
> > > the LCD is one of the major problems with this fantastic instrument. I
> >
> > > follow along with the group e-mail, and only speak up every now and
> > > then and this seemed like a good time. I would really like to have the
> >
> > > knowledge to successfully get that LCD installed.
> > >
> > > Bruce
> > >
> > > ----------------------------------------------------------
> > > *From:* [email protected] <k5synth%40yahoogroups.com> [mailto:
> > [email protected] <k5synth%40yahoogroups.com>] *On
> > > Behalf Of *Antoine Deschênes
> > > *Sent:* Tuesday, January 15, 2008 10:38 PM
> > > *To:* [email protected] <k5synth%40yahoogroups.com>
> > > *Subject:* Re: [k5synth] Re: K5 Repair Issues
> > >
> > > Yep, when the power switch wire broke on my K5, I searched for three
> > > days why my K5 wasn't powering on ;-).
> > >
> > > To change the viewing angle of the LCD, you can adjust the CONTRAST
> > > knob on the back of the synth to make it more comfortable.
> > >
> > > The inverter is the "Nichia" branded white box on the power supply
> > > board you talked about in a previous mail. I'll post a picture (if I
> > > think about it) and try to tell you how to connect the new inverter (I
> > > didn't buy a new inverter)
> > >
> > > 2008/1/15, ink_blot2001 <ink_blot2001-/[email protected]<ink_blot2001%40yahoo.com>
> > > <mailto:ink_blot2001%40yahoo.com>>:
> > >
> > > > I checked around inside. Apparently one of the wires connected to
> > > the power switch was
> > > > disconnected. I re-soldered it. That almost seems as bad as
> > > forgetting to plug it in. After
> > > > turning it on, I noticed two things: the backlight I just installed
> > > does not work, and I can't
> > > > see the text when I look directly down at the display. I don't
> > > remember the latter being
> > > > the case prior to my "repair". I realize that the backlight not
> > > working signifies the inverter
> > > > is bad. What about the text? I now need to look at the display at a
> > > slight angle. This isn't
> > > > an issue, but I don't understand why this is.
> > > >
> > > > Also, any information, like where it is located and what it looks
> > > like, about the inverter
> > > > would be appreciated. An image would be wonderful. I checked out the
> >
> > > link you posted,
> > > > but would like more information before I try "fixing" the keyboard
> > > anymore.
> > > >
> > > > Ivan
> > > >
> > > >
> >
>
-- 
Antoine Deschênes