Quote:
Originally Posted by erick
I recently came by a Kendrick Dew Controller Model VI. Adverts say it is a pulse width modulation design from 40% to 100%. One control knob, four outlets. Control knob has an on/off switch built in.
When I put the output on the oscilloscope, loaded or unloaded, all I see is 0 volts out in the off position and 12volts out in any control position. "Houston, I think we have a problem here." Just before I drill out the rivets so I can get the lid off and have a look inside, is there anything I am missing here?
I have a home built PWM supply and I swapped that into place instead of the Kendrick and I saw the pulses, under control, as I expected.
Anyone know if I can get a circuit from anywhere? From Kendrick given this is a superseded model?
Thanks
Eric  |
Hi Eric
They are easy to repair. I just repaired one with the same symptoms. It turned out to be just the 555 timer but I also had a new driver transistor available. I did trace out the circuit but did not keep it . It was pretty straight forward. I cut the timer out to avoid pcb damage and installed a socket.
Barry