Toshiba laptop charger power supply problems

[stj]

Re: Toshiba laptop charger power supply problems

what multi-meter do you have ? i want one that does that

they all do that - once!
well maybe the 20A ones could do it a few times atleast - the cap can only hold a couple of amps if your lucky.

[Per Hansson]

Re: Toshiba laptop charger power supply problems

what multi-meter do you have ? i want one that does that

I am thinking that this person is just seeing the capacitor slowly discharging

Because I also seem this myself

Some multimeters have a low impedance mode, with a 3K series resistor instead of 10M.
Those can be quite useful to discharge capacitors unless the capacitor is really large.
(If it is then the PTC's inside the meter will heat up and the resistance increases so they discharge much slower).
Some more details here: https://www.badcaps.net/forum/showth...076#post886076

[noizemaker]

Re: Toshiba laptop charger power supply problems

what could other benefit of a Y cap like 4700pF have on a Notebook charger?

[noizemaker]

Re: Toshiba laptop charger power supply problems

Speaking of notebook chargers, is it safe to remove Y cap from my Notebook charger (Lenovo Ideapad)? there is only one. I think it's connected to neutral-ground to filter EMI
However I'm using a surge suppressor with 2 Y caps
The Y cap in question on the charger is ce472m STE Y2 4700pF (quite high right?)

[sam_sam_sam]

Re: Toshiba laptop charger power supply problems

I am thinking that this person is just seeing the capacitor slowly discharging

Because I also seem this myself

[petehall347]

Re: Toshiba laptop charger power supply problems

what multi-meter do you have ? i want one that does that

[SuperAman]

Re: Toshiba laptop charger power supply problems

Remove all the white gunk from the board and post some nice clean photos.
Also, the most left cap ( c102? ) on the secondary side looks like a goner to me. Oh, and keep in mind that shocking yourself with a capacitor is not always the best way to check if it is ok or not.

Ok will do. I accidently shocked myself, since it didn't show a short on the light bulb test, assumed it was ok. I am discharging the cap with my multimeter now after each time the charger has been plugged in.

[madan1]

Re: Toshiba laptop charger power supply problems

Remove all the white gunk from the board and post some nice clean photos.
Also, the most left cap ( c102? ) on the secondary side looks like a goner to me. Oh, and keep in mind that shocking yourself with a capacitor is not always the best way to check if it is ok or not.

[petehall347]

Re: Toshiba laptop charger power supply problems

if I don't discharge the cap with my meter and I touch the board cap area, I am shocked very badly.

are you for real ?

[SuperAman]

Re: Toshiba laptop charger power supply problems

So, are you saying that this big capacitor 82 uF, 420V has 600V??? This doesn't sound right.

I am saying it is storing voltage, it is not going to the secondary or output side. I am measuring in AC so that might be why the number is high. Whatever the case, the cap stores voltage and when I use a lightbulb (serial bulb circuit) to test, it shows no short. However, if I don't discharge the cap with my meter and I touch the board cap area, I am shocked very badly.

[Askic]

Re: Toshiba laptop charger power supply problems

So, are you saying that this big capacitor 82 uF, 420V has 600V??? This doesn't sound right.

[SuperAman]

Re: Toshiba laptop charger power supply problems

[SuperAman]

I have a laptop charger that is not working. I have tested it and the capacitor is storing high voltages around 600v. Both transistors are reading ok as well as all the diodes including the bridge diode. I replaced the C139 cap on output mosfet (it was cracked). All the resistors test ok in circuit. Am I missing something? D32 has a partial short reading in circuit but with one pad removed it has correct diode readings. The model of the board is adp-45fe bb.