); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY [EMAIL PROTECTED] wrote: > Hi Bruce, > > I got it to work, it even locks to -5Hz within 5 minutes and the Amber LED > goes off. > > The problem was that I had only applied GND to the shield of the connector. > I added a wire to the EFC pin to EFC return, and connected the three GND pins > of the connector, and magically it started working. > > Seems one of those "GND" pins is actually a "heater on" type of pin. > > Now I will do some experiments, it seems EFC should be 2.5V for the output > to be on frequency (not 0V). > > Another interesting observation: my unit has 2.532V on the reference output. > I could probably try to locate the reference, and replace it with something > more modern and stable. > > Lastly, the unit seems to have a slow 2-4 second sinusoidial drift in parts > to the -11 when measuring it's output on my 53132A after about 10 minutes > warmup. Wonder if that's the oven heater control loop... > > bye, > Said > > Said
There are 3 LT1121I 2.5V references on the board, one located near the ADC, one near the devices with heatsinks and yet another near the 4 pin header at the rear of the board (end nearest the D - connector). There may also be one inside the oven - the osc.pdf paper indicates this. As long as the voltage is stable the exact value is unimportant. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
