Ryobi 18v BCL14181H MY2015 charger dead

[SKP]

Hi,

I have this EU-version of Ryobi charger which doesn't show any lights when plugged in, but the green led blinks after disconnecting it from the wall socket.

I started troubleshooting by reading this thread https://www.badcaps.net/forum/showth...ighlight=ryobi but I guess it is for an older model.
I found couple of SOT-23 mosfets/transistors which look pretty bad (Q5, Q3). Cannot see any markings on them, does anyone know what they are and could these be the reason why the charger doesn't work? Similar components can be found on the PCB with markings 1AM and 702…

No voltage on BAT+/BAT-, but main cap has 330ish volts and 50V 470uF cap on the secondary side has 30V after unplugging so at least something is getting from primary side to secondary side?

I'll clean the board tomorrow with IPA and start measuring diodes, resistors, caps etc but can someone give me some guidance what to measure and what to look for?

Thanks!

[stj]

Re: Ryobi 18v BCL14181H MY2015 charger dead

start by resoldering the main transformer and r9
they have bad joints

[budm]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Is the fuse (red body) F2 (right next to ZD4) OK?
It is an always on power supply that is why you are getting 30V on the cold side.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Thanks guys, I'll check the joints. Fuses are ok, forgot to mention it..

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

The markings on Q3 and Q5 are now visible, both are 1AM. And they look ok.

While resoldering I managed to burn one of the pads on the EC2 near R9… now it has a very dodgy looking repair, but it works. Maybe my ThermoPasty flux gel wasn't the correct option and that's why the pad got burned, don't know.

[stj]

Re: Ryobi 18v BCL14181H MY2015 charger dead

why you using flux?
you only need flux for hot air reflow

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

I probed around on another functioning board and found two SMD caps on faulty board, C10 and C19, which were measuring different values compared to the functioning one.
140-160uF on the faulty and 300-330uF on the functioning board.
Maybe I’ll change them when my spare parts arrive.
All the other components, except IC2 and IC3 which I didn’t measure, gave similar values between the two boards.

With flux, I basically tried to cut corners and get the old solder to flow easily to the pad… bad idea.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

And of course nF, not uF..

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Does anyone have any ideas on this?
I guess the caps are not the problem.

[R_J]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Do you have any voltage across the filter cap in the secondary? On the bottom view there is a chip cap marked C9 which is also across that cap.
You won't have any voltage across the battery terminals unless a good battery is connected.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Do you have any voltage across the filter cap in the secondary? On the bottom view there is a chip cap marked C9 which is also across that cap.
You won't have any voltage across the battery terminals unless a good battery is connected.

Thanks for your reply.
Before I noticed your message, I measured the board live and noticed pulsating voltage on EC2 near D2, it was 9-13ish volts. And on the working charger there's steady 19.9 volts. Something to do with defective IC1 or what else could make it pulse like that?

C9 had 7.41v if I remember correctly, and on a working board it was 15.4v. I guess that filter cap had the same 7.41v.

[R_J]

Re: Ryobi 18v BCL14181H MY2015 charger dead

There is a small electrolytic beside D2 in the primary, I would replace it. And another small one in the secondary marked ECP?

It seems like the power supply is in burst mode, A low vcc to the primary switching ic could cause this.
Check and post the voltage ACROSS the elec. cap. next to D2, this should tell us what the state of the ic is in.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Unfortunately I’m not able to test it for couple of weeks.. but I’ll order some parts and hopefully they have arrived once I get back. Then I’ll get back on ”fixing” this thing.

Next to D2 is EC2 which was pulsating 9-13ish volts.

[R_J]

Re: Ryobi 18v BCL14181H MY2015 charger dead

The primary pwm controller will shut down at 10v on the VDD (VCC) pin, I would replace EC2 first and see what happens.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Ok, thanks for the help!

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

At last I had a chance to get back to this!
Spare parts had arrived as well so I replaced some parts, including IC1, Q1 and EC2.
After plugging in green and red LEDs blinks, so I didn't fix it yet. Measured EC2 and it's still 10-14ish volts...
Next step replacing the small EC6 in the secondary?

[stj]

Re: Ryobi 18v BCL14181H MY2015 charger dead

you should have just changed all the electrolytics in one go.
atleast you have a newer board that doesnt have the diode problem.

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

I was just about to do that, but they forgot to send me the replacement for EC6 1uf/50V. Great…

[SKP]

Re: Ryobi 18v BCL14181H MY2015 charger dead

Changed all the caps. Borrowed the replacement EC6 from another charger.
But still the LEDs blink.

[stj]

Re: Ryobi 18v BCL14181H MY2015 charger dead

what do the leds usually do if you have no battery connected?