On Saturday, July 8, 2017 at 9:58:10 PM UTC-4, wrote:
On Saturday, July 8, 2017 at 7:15:05 PM UTC-4, Dimitrij Klingbeil wrote:
On 07.07.2017 19:36, rickman wrote:
wrote on 7/7/2017 1:01 PM:
On Friday, July 7, 2017 at 12:09:33 PM UTC-4, rickman wrote:

The charge pump circuit was bothering me as the diode seemed to be
backwards. Then I realized it isn't making 24 volts from 12 volts, it's
pumping up the 24 volts to something higher! What is the voltage on
pin 3
of the LA7833? The cap is only rated for 35 volts, so it isn't
making 48
volts. But clearly pin 3 should have something on it higher than 24
volts.
What does the pump drive signal on pin 7 look like?

--

Rick C

pin 3 of 7833 is 25.65 v. pins 2 and 15 are opposite polarity. pump
drive signal is a .5 volts upside down sawtooth.

i appreciate the time taken here. i could just send this out, but i
think i am close, just not there.

If pin 7 pump drive signal is only half a volt, I would say your problem
is there. Pin 3 should clearly be more than 25 volts and it is this
signal that drives that voltage. Is pin 3 at all steady or is it also a
waveform? You should measure the voltage with the scope, not the meter.