Vintage Synth Repair

Hi Eons,

Someone has either dropped the synth and it banged the display or they had it apart and put it back together wrong. The LCD glass is not aligned with the rubber strips and the driver pcb. You will need to bend the metal tabs and remove the glass. Then the rubber strips need to be aligned perfectly with the contacts on the driver board and the glass. If you look very closely you can see the etching in the glass for the connections. I usually mark everything before disassembly so the glass doesn't get installed upside down. Also there may be a cable that connects the driver board to the glass. These can be damaged and cause bad connections. The KN2000 probably has this type of display because it's so large. It looks similar to a Casio FZ & VZ display.

I've seen where individuals have tried using superglue to hold the rubber strips in place. The glue gets into the connections and messes the display so lines are missing. Let us know what you find....

Fran

--- In vintagesynthrepair@yahoogroups.com, "eons" <laser@...> wrote:

>
> Hi all,
> 
> I have KN2000 for repair that has display with lines (randomly striped display).
> 
> Replaced the 14-wire harness as someone interfered with the end that fits into socket resulting in a bad connection. But still the new harness has made no difference regarding the strips.
> 
> Anyone been here before and/or has service manual to share please?
> 
> Thanks guys for any help or suggestions,
> 
> eons
>

Hi Fran,

Thank you very much for your suggestions and help.

To tell you the truth I've already dismantled the LCD to inspect but I did not take the plunge and remove the glass from the rubber contact.

I will dismantle LCD again and do so this time maybe I'll be lucky and fix it or else could get worse!

I've done this with Casio synths before but this Technics's rubbery contacts seemed quite stuck securely to the glass. However I've noticed the contact strip slightly bent horizontally, that is, not in a perfect straight line.

Will let you know the outcome ok.

eons

Hi Eons,

Someone has either dropped the synth and it banged the display or they had it apart and put it back together wrong. The LCD glass is not aligned with the rubber strips and the driver pcb. You will need to bend the metal tabs and remove the glass. Then the rubber strips need to be aligned perfectly with the contacts on the driver board and the glass. If you look very closely you can see the etching in the glass for the connections. I usually mark everything before disassembly so the glass doesn't get installed upside down. Also there may be a cable that connects the driver board to the glass. These can be damaged and cause bad connections. The KN2000 probably has this type of display because it's so large. It looks similar to a Casio FZ & VZ display.

I've seen where individuals have tried using superglue to hold the rubber strips in place. The glue gets into the connections and messes the display so lines are missing. Let us know what you find....

Fran

--- In vintagesynthrepair@yahoogroups.com, "eons" wrote:
>
> Hi all,
>
> I have KN2000 for repair that has display with lines (randomly striped display).
>
> Replaced the 14-wire harness as someone interfered with the end that fits into socket resulting in a bad connection. But still the new harness has made no difference regarding the strips.
>
> Anyone been here before and/or has service manual to share please?
>
> Thanks guys for any help or suggestions,
>
> eons
>

Hi,

I've dismantled the LCD display again and this time separated the glass together with rubber contacts strip from the backing pcb (note: the rubber contacts strip is glued to the glass). Cleaned the pcb track contacts slightly with rubbing compound then alcohol. But fitting back again has made no difference at all I'm afraid. I'm suspecting a faulty Graphics Controller IC found on the mother board. I tried to juggle the glass slightly from pcb with my hands while this was still out with everything connected and keyboard switched-on but although this made the display go on and off at various places, it made no difference to the blank horizontal lines mentioned earlier.

So I'll have to leave it at that until maybe I'll have another KN2000 I could check with and anyway now that Technics are not manufactured anymore, I think obtaining parts would be quite a headache.

Thank you folks for your help and if you have some more ideas please do send them in.

Cheers,

eons

Hi Eons,

Someone has either dropped the synth and it banged the display or they had it apart and put it back together wrong. The LCD glass is not aligned with the rubber strips and the driver pcb. You will need to bend the metal tabs and remove the glass. Then the rubber strips need to be aligned perfectly with the contacts on the driver board and the glass. If you look very closely you can see the etching in the glass for the connections. I usually mark everything before disassembly so the glass doesn't get installed upside down. Also there may be a cable that connects the driver board to the glass. These can be damaged and cause bad connections. The KN2000 probably has this type of display because it's so large. It looks similar to a Casio FZ & VZ display.

I've seen where individuals have tried using superglue to hold the rubber strips in place. The glue gets into the connections and messes the display so lines are missing. Let us know what you find....

Fran

--- In vintagesynthrepair@yahoogroups.com, "eons" wrote:
>
> Hi all,
>
> I have KN2000 for repair that has display with lines (randomly striped display).
>
> Replaced the 14-wire harness as someone interfered with the end that fits into socket resulting in a bad connection. But still the new harness has made no difference regarding the strips.
>
> Anyone been here before and/or has service manual to share please?
>
> Thanks guys for any help or suggestions,
>
> eons
>