LCD backlight repair for Roland D-50+70 ?
Si
backlight inverters (D-70, D-550, PG-1000).
To those who have already faced and solved the same problems, thanks for
answer to the following questions:
-Where does one find a higher frequency inverter (with PZT @ 60 kHz) ?
-Is the fluorescent sheet behing LCD worn, and to be replaced too ?
I modded the D-70 lighting with a laptop LED lamp.
Si
D-70 replacement EL backlight: backlights.telesisgear.com
inverters: www.jkllamps.com , www.supertex.com
Discovered how to quiet D-550's backlight hum (made mostly by the EL
sheet itself, not the inverter): either lower the frequency below 200 or
raise it above 10000 (but stay below 20000). Interesting effect: raising
the frequency shifts the color from green to blue.
Merry Christmas and happy hacking !
Mikael Willberg
Si <silici...@rmony-p.ath.cx> wrote:
>
>Discovered how to quiet D-550's backlight hum (made mostly by the EL
>sheet itself, not the inverter): either lower the frequency below 200 or
>raise it above 10000 (but stay below 20000). Interesting effect: raising
>the frequency shifts the color from green to blue.
Interesting, I have not noticed whining from my D-550, although I'm
very sensitive to annoying little noises that no one else seem to
notice. The EL is quite bluish, but dimmed.
To compare, my W-30 has very annoying low frequency whine which I
could not remove by replacing Q1 on Main Board. Mostly because I could
not locate correct known-to-remove-whine transistor from anywhere, the
nearest alternative available didn't do anything so I ended up
disabling the inverter. Now it is deadly quiet. The display is quite
readable in normal light, but it looks like those pocket calculator
displays 8-)
Mig
--
**** Mikael Willberg ***** "Oh dear", says God, "I hadn't thought of that" **
* * and promptly vanishes in a puff of logic. *
* Tampere * (Douglas Adams) *
******** Finland ************************************************************