Hi David,
VR3059 and Q3052 can cause troubles, but how would you explain that a failure there causes the inverter to stop (fall back in tick mode) when the line voltage is increased from too low to normal?
Albert
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--- In TekScopes@..., David <davidwhess@...> wrote:
Are you equipped to make safe primary side oscilloscope measurements?
When you say you checked the primary side zener diodes, do you mean
all of them including VR3059? Did you check them for leakage?
Besides measuring the voltages at the various pins of U3105 to see if
it is initiating the shutdown, I would check the circuit around Q3052
and see if it is triggering at normal AC line voltage.
What resonate frequency is the inverter operating at? Maybe there is
a problem with L3037 or C3037.
On Tue, 23 Oct 2012 16:49:02 -0000, "hojo3008" <j_massengale@...>
wrote:
Hi,
I have a 7704A power supply that will not work at normal line voltage but seems happy and regulated at 70 to 100 volts in. Zeners and caps in the inverter have been rechecked and verified okay. 2 inverter chips(-02s) work the same. The 54V adjust is right on as is the -50V adjust. The voltage select looks okay. Ideas?
