开云体育

I have a 577 that is a very early serial number "B0100124" and it has some issues with convergence of the calibration. I have tracked this down to lots of out of spec components on the analog board (looking at the front right side of the unit lower board.) I also had some non factory opamps in this scope. I agree it is unlikely that all 4 amps went bad at one time unless something happened with power supplies. but I did end up scratching my head at the amplifier board to the point of testing almost every component in the amp board and coming up good led me to the control board. I have not gone in to that one yet and I am not sure I want to rebuild it given the serial number as well as having a few other curve tracers in the lab. If it was not an early example I would have rebuilt the board with modern components but still on the fence about this one.

One thing I also noticed is the adjustment range on the earlier units is much smaller than the adjustment range on the later units. I also prefer the dual pot arrangement on the later 577's for positioning. Now that I think about it is the 10X magnifier some how enabled? On the early units it was a pull pot on the later units is was a pushbutton to pop the center control out.

Zen