Allen, The EL "black box" is an oscillator. The output voltage varies with the input (battery) voltage that is adjusted by the dimmer knob on the dash. The high voltage output is an AC voltage. I took one of these to work years ago and did a little bench testing: I measured a whopping 790 Volts peak-to-peak with a frequency of 294 Hz (an AC voltmeter will give reading of about a third of this -- around 250 Volts RMS). The oscillator is pretty crude and the circuit suffers from the aging of a capacitor (it gets leaky and loads down and finally shorts the high voltage output) but the EL dash is pretty darned high tech even by today's standards! John B. On Fri, 25 Jan 2002 23:10:25 -0500 bandmgrinding@xxxxxxxx writes: > Hi John, > Thanks for the info. You don't happen to know what the output of > they) > " black box " should be and how it varies the dash lights? Is it the > cycles per second or the output voltage that changes. The shop > manual > just says 200 volts and 250 cps in the radio diagram, nothing about > what > controls it. > Thanks > Allan R. > >