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Old 02-15-2020, 03:04 PM   #21
R_J
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Default Re: Help with car battery charger HT7715

That is why I asked for a voltage check across the cap in post #10, If there is no voltage across that cap there is no secondary voltage so the click can not come from the relay.

Almost all pwm ic's will pulse the primary circuit at least once (click) this pulse should produce enough voltage across C24 to raise the vcc above the start threshold of the ic.
The Dc voltage should be measured across the outside leads of the bridge rectifier (+ and -) or just measure the voltage across the large capacitor in the primary. It should be around 325VDC

Last edited by R_J; 02-15-2020 at 03:07 PM..
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Old 02-15-2020, 03:07 PM   #22
budm
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Default Re: Help with car battery charger HT7715

It is 12vdc relay coil (OKS2C-S15DC12V).
See attachment as to what I believe how the relay is driven.
I would expect the clicking to be continuous if the power supply is stuck in start/stop loop if it is in protection mode or due to bad startup/running cap.
BTW, the click sound of the relay will be so much more metallic sound than the clicking of the SMPS circuit.
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Last edited by budm; 02-15-2020 at 03:22 PM..
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Old Today, 08:32 AM   #23
ex250
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Default Re: Help with car battery charger HT7715

Changed the cap C24 with a new one, same behabior than before.
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Old Today, 01:48 PM   #24
R_J
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Default Re: Help with car battery charger HT7715

Check the voltage on C24, You must use the hot side ground, (- of bridge or - of primary cap). If you have o volts, (with power disconnected) check the resistor marked 104, and the resistor on the top side connected to it, also check the large 3 watt resistor next to the heatsink beside the fet.
If you can provide the numbers of the two 8 pin ic's that would help, they may be hard to read due to the coating

In the past did this charger come on when only pluged into the mains? or did it require the 12 volt battery be connected first?

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