X-No-Archive: yes "John Fields" wrote : (Hallvard Tangeraas) wrote: : : >I'm servicing a friend's music sampler (Akai S-1100) which has a worn : >out backlight for the LCD. As far as I can tell, this is of the : >"electro-luminensce" (EL) type. : >
: >It's very thin, has two electrodes fastened to one end (which is : >attached via a cable to a small transformer). It's pink on one side : >and silver on the other and has a transparent coating over both sides. : >It doesn't light up at all (which I'm sure I would see if it did light : >up), so I suppose it's dead. : : --- : It may be that the inverter is dead, not the lamp. : : With the lamp disconnected from the transformer, check the resistance : across the lamp terminals. It should be infinite. If it isn't it's : bad. Also, if it's not shorted, check the capacitance across the : lamp's terminals. It should be in the range of tens to hundreds of : nanofarads. If it's OK, then check the inverter with the lamp plugged : in. It should should put out high voltage AC; probably less than a : couple of hundred volts peak-to-peak and less than 2000 Hz. (WAG, it : depends...) : : Bottom line is if your inverter works but the lamp stays dark then : yeah, it's the lamp. :
It is probably the inverter. however if you can isolate the two terminals for the lamp -- And only if you can. You can test the lame by connecting it to a source of 120VAC at 50 or 60 HZ. In reduced light it should light. If it lights the inverter has failed. A voltmeter across the two terminals of the inverter should show about 120 to 140 Vac at about 400 to 2,000 HZ.