D
Dave Bullock
- Jan 1, 1970
- 0
Dear Repairers....
I have a very nice 12V to mains electricity inverter that won't start up.
It is a Sinergex Pure Watts 1000, S/N 206756
It looks as though the unit is almost working as when power is applied
the buzzer momentarily sounds, and the bargraph displays the operating
voltage correctly.
I have begun to trace out the circuit and probe around with an
oscilloscope and test meter. The sawtooth oscillator on the TL598 (PWM
controller) is running and one of the error amplifiers (No2) is OK.
However error amplifier 1, seems to be being activated by the opto
coupler U8 (PC817). This signal is prohibiting the sawtooth from
operating the pulse steering 'flip-flop' and hence the output gates and
power FET's. (i.e. the FB pin has 3.5v dc on it, whilst the sawtooth is
only 3V peak)
To save me the effort of tracing out the rest of the circuit I wondered
if anyone has a schematic, or have any 'stock faults' they can tell me
about to ease this repair?
The output waveform system appears to be functioning as the MC14060's
oscillator is running and the dividers operating, although I haven't
traced this part out fully yet!
I tried emailing Sinergex and get a 'mailbox doesn't exist message'
<[email protected]>
Please help if you can.
I have a very nice 12V to mains electricity inverter that won't start up.
It is a Sinergex Pure Watts 1000, S/N 206756
It looks as though the unit is almost working as when power is applied
the buzzer momentarily sounds, and the bargraph displays the operating
voltage correctly.
I have begun to trace out the circuit and probe around with an
oscilloscope and test meter. The sawtooth oscillator on the TL598 (PWM
controller) is running and one of the error amplifiers (No2) is OK.
However error amplifier 1, seems to be being activated by the opto
coupler U8 (PC817). This signal is prohibiting the sawtooth from
operating the pulse steering 'flip-flop' and hence the output gates and
power FET's. (i.e. the FB pin has 3.5v dc on it, whilst the sawtooth is
only 3V peak)
To save me the effort of tracing out the rest of the circuit I wondered
if anyone has a schematic, or have any 'stock faults' they can tell me
about to ease this repair?
The output waveform system appears to be functioning as the MC14060's
oscillator is running and the dividers operating, although I haven't
traced this part out fully yet!
I tried emailing Sinergex and get a 'mailbox doesn't exist message'
<[email protected]>
Please help if you can.
