I am having trouble fixing a xantrax truecharge 20i battery charger.
I have recreated part of the schematic that I am looking at the best I could:
**broken link removed**.
It stopped working while it was connected to a small 240V 720 watt generator. Had 2 identical chargers running at the time. One quit when the ac voltage went to 265 volts. The genny didn’t have the power to blow anything up, not even a 4A fuse, but several components were shorted so fully loading the genny.
I have replaced all transistors, both MosFets, all 3 zenners, both optocouplers and the uc3845. Have checked all resistors (in circuit). The other diodes appear to be ok (in circuit) and the capacitors also seem to be ok (again in circuit). The only test instruments I have are a multi meter, An esr/low ohms meter and a simple transistor checker.
The circuit doesn’t self start. I am reading 7.7 volts at pin 7 of the ic when it should be over 8 volts.(needs 7.9 v min)
I have tried to reduce the value of R5 with no effect. C28 reads ok with my ESR meter
I have got the circuit going by injecting 12V to pin 7 till the processor (not shown) that drives the opto couplers, fires up, then circuit runs. The voltage at pin 7 is then still low at about 9.5 volts when it should be somewhere near 14V. Also noted that the 2n2222 that drives T1 gets quite warm when it shouldn’t.
Have swapped C19 from another location and even swapped T1 from the 2nd charger. Have changed c25, all with no effect.
Have measured the resistance of each pin of the ic to ground on both chargers and they match quite well. Have swapped the ic in both chargers as well with no effect.
Have measured the voltage on each pin of the IC while it was running. Have noted that while measuring pin 4, noise comes from the charger, where as doing the same on the 2nd charger, nothing happens. Same happens when I measure the voltage on the upper opto coupler output
Can anyone shed any light on what to change or try next?
Also, does anyone have a full schematic
I really don’t want to swap componants over too much. There are many heavy tracks and have damaged some while desoldering in the charger I am trying to fix.
James
I have recreated part of the schematic that I am looking at the best I could:
**broken link removed**.
It stopped working while it was connected to a small 240V 720 watt generator. Had 2 identical chargers running at the time. One quit when the ac voltage went to 265 volts. The genny didn’t have the power to blow anything up, not even a 4A fuse, but several components were shorted so fully loading the genny.
I have replaced all transistors, both MosFets, all 3 zenners, both optocouplers and the uc3845. Have checked all resistors (in circuit). The other diodes appear to be ok (in circuit) and the capacitors also seem to be ok (again in circuit). The only test instruments I have are a multi meter, An esr/low ohms meter and a simple transistor checker.
The circuit doesn’t self start. I am reading 7.7 volts at pin 7 of the ic when it should be over 8 volts.(needs 7.9 v min)
I have tried to reduce the value of R5 with no effect. C28 reads ok with my ESR meter
I have got the circuit going by injecting 12V to pin 7 till the processor (not shown) that drives the opto couplers, fires up, then circuit runs. The voltage at pin 7 is then still low at about 9.5 volts when it should be somewhere near 14V. Also noted that the 2n2222 that drives T1 gets quite warm when it shouldn’t.
Have swapped C19 from another location and even swapped T1 from the 2nd charger. Have changed c25, all with no effect.
Have measured the resistance of each pin of the ic to ground on both chargers and they match quite well. Have swapped the ic in both chargers as well with no effect.
Have measured the voltage on each pin of the IC while it was running. Have noted that while measuring pin 4, noise comes from the charger, where as doing the same on the 2nd charger, nothing happens. Same happens when I measure the voltage on the upper opto coupler output
Can anyone shed any light on what to change or try next?
Also, does anyone have a full schematic
I really don’t want to swap componants over too much. There are many heavy tracks and have damaged some while desoldering in the charger I am trying to fix.
James