Giant ebike li-ion charger

[Cobblers]

29.2 volt li-ion charger

Has mains input but no dc output

2.5 glass fuse on primary side was blown

I had to solder on a removable fuse holder
Then installed a 2.a fuse to test but in instantly blew again.

I've removed the heat sink so I could take a better picture.

Any ideas what I should test?

[diif]

Re: Giant ebike li-ion charger

The bridge rectifier and the mosfet.

[Cobblers]

Re: Giant ebike li-ion charger

Yes found the mosfet is shorted across all 3 terminals out of circuit. With it removed the fuse doesn't blow and I get 330v dx accros the big capacitor. I've ordered the mosfet and will give it a try.

[stj]

Re: Giant ebike li-ion charger

if all 3 pins are shorted then it may have damaged the circuit connected to the gate pin

[budm]

Re: Giant ebike li-ion charger

SMPS IC101 in the Hot side probably is damaged too, you also need to check the low Ohm Source pin resistor (Brown/Black/Silver/Gold???) to gnd and also any parts connected between Gate and Drive output of the SMPS IC for damages.

[Cobblers]

Re: Giant ebike li-ion charger

I'm not sure how to test the ic101.

I've tested
R108 ok
R106 ok
R105 ok
R103 and 104 ok
D102 ok

Not sure how to test the ferrite bead
But measuring no resistance across the 2 pins


Checking r112 it measures 0.5 ohms
The calculator says it should either be 0.1 ohm or 0.2 ohm depending whether or not the first band is red or brown I think it is red personally but not 100% sure. Tolerance is stated as 5% so it should be between 0.19 and 0.21 do you think this is failed?

[petehall347]

Re: Giant ebike li-ion charger

ic101 is showing signs of being hot

[stj]

Re: Giant ebike li-ion charger

Checking r112 it measures 0.5 ohms
The calculator says it should either be 0.1 ohm or 0.2 ohm depending whether or not the first band is red or brown I think it is red personally but not 100% sure. Tolerance is stated as 5% so it should be between 0.19 and 0.21 do you think this is failed?

touch your probes together, your probably seeing the resistor + losses in your probes/cables
most meters have a .2-.4 ohm loss in the cables

[budm]

Re: Giant ebike li-ion charger

I would replace the IC unless you want to take a chance of blowing up the new MOSFET. you cannot fully test the IC with the meter.

[Cobblers]

Re: Giant ebike li-ion charger

Minimum order for the new mosfet was 5 from rs so I have spares. The meter I'm using is a hantec 2c72 in dmm mode. It is also a occiloscope work bought them for us however I've never used it as a scope I I'm worried about doing more damage to the board by probing the wrong parts

I will have to do some more learning I think

[Cobblers]

Re: Giant ebike li-ion charger

OK so new mosfet arrived.

It lasted approx 5 seconds and now I have a hole where ic 101 used to be.

I've been Trying to find one online but without success luckily I have a half decent photo of the part number but have been unable to find the exact part number so at the moment I'm stuck.

Does anyone have any ideas?

[budm]

Re: Giant ebike li-ion charger

FUJI FA5518.
You must check all the component between the Gate of the MOSFET and this IC and other components connected to the IC.

[Cobblers]

Re: Giant ebike li-ion charger

I damaged the board while removing the chip so thanks for all the help I've ordered a new charger