I will post again with the results of my second attempt, however, I may not try again for a few days.ĭisplay problem may be contrast knob or tarnish on ribbon cableīefore purchasing a replacement LCD, try a couple of things first:ġ) Adjust the contrast knob on the back to see if you can make the image usable.Ģ) Clean flex tail contacts: If it has vertical streaks or half is blank, the LCD display is quite possibly good but contacts on the flex tail fingers are tarnished, producing poor contact at the connector. I hope this helps anyone else looking to repair without purchasing new parts. Over 100 screws to take this thing apart and an hour time to toy with it and put it back together. Clearly a new LCD should not be necessary and I will attempt to take apart my keyboard again this time cleaning all display connections as well as the end of the display cable. However, once all put back together and after playing the keys for a few minutes the display problem came back. Results: I managed to find a sweet spot where the cable would recieve a good signal and the display problem disappeared completely. This way I was able to play around with the cables while seeing if the display problem got any better.ĭiagnosis (in my opinion): I believe the end of the display cable is the problem and not the double crimped portion of the ribbon. Once the screen was facing me I plugged in the AC power. Once I got the keyboard apart I pulled the screen out and plugged it back into the main board except now I had the screen facing me while the keyboard was open.
So, instead I attemtped to take the DGX620/YPG625 keyboard apart hoping I could get the display working without buying a new part. However, I'm a total cheap skate and don't want to part with $150 to buy a new screen. The T12-D4 is wide enough to ‘re-glue’ 4.5 pins at one iteration, so, total process took 2…3 minutes (and 30…40 minutes to disassemble/assemble keyboard). Then I just pressed (press hard but no too hard, film’s datasheet says ~18kg/cm2) and held for ~10 seconds by warm soldering tip on the flex’s pins over the places where they are glued to the PCB. I’ve set 140 0C soldering tip temperature. I’ve used Hakko T12-D4 soldering tip (flat and thin but not sharp). This film may ‘delaminate’ in case of hard knocks(actually not too hard, typical datasheets say ‘~0.5kg/cm2 pressure is enough’). It seems that Yamaha(or who manufactured this LCD assy – I do not know) uses some kind of anisotropic conductive film(instead of solder or connector) to connect those two flex cables to the PCB. The problem is in poor contact in-between LCD’s PCB and flex cables that comes to the LCD panel(two cables). I have got similar issue (half/stripped LCD) – it happened after my little son knocked hard on the LCD screen.
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