Ego 56V battery charger dead

[braxton]

I would like to try to repair an Ego brand standard 56V battery charger. The model number is CH2100.
There is a brief YouTube video on it here:
https://m.youtube.com/watch?v=2cYAKUuVgUE

The charger appears to be completely dead. Upon disassembly I found the glass fuse is ok. The only visible damage was a completely blown ceramic capacitor behind the two largest caps.

I am attaching a few photos with arrows to the location of the blown component.
I’m hoping for some suggestions as to what might have caused the cap to blow and how to troubleshoot further.

[petehall347]

see if its shorted and check whatever its connected across ..might be a fet .

[budm]

That is a snubber cap connected in parallel with Sourde and Drain pin of the MOSFET. Can you still read what is printed on the cap?
You also need to check the Low Ohms resistor connected between the Hot side circuit ground and the Source pin of the MOSFET to make sure it is not blown open circuit when that cap shorted out, if that resistor is blown the SMPS IC that drives the MOSFET can be damaged also.
Did you check the resistance between Source and Drain pin of the MOSFET after removing the blown cap?

[braxton]

The Cap was blown pretty badly so could not read what was on it. I think it might have been a 2.2nf 1KV cap. I replaced it with a 2.2nf 250V cap but still no life from the charger. It does not appear to be shorted across the 2 pins of the cap. The 2 outside contacts of the mosfet seem to have continuity though.

[budm]

Originally Posted by braxton

The Cap was blown pretty badly so could not read what was on it. I think it might have been a 2.2nf 1KV cap. I replaced it with a 2.2nf 250V cap but still no life from the charger. It does not appear to be shorted across the 2 pins of the cap. The 2 outside contacts of the mosfet seem to have continuity though.

1) That cap has to be at least 1KV rating, more likely that it is 220pF 1KV but I would use 2KV since this is commonly failed cap.
2) What is the exact resistance do you get when measure between Source and Drain pin? You do know what each pin of the MOSFET is correct?
3) Did you check the Source pin resistor as I suggested?

[braxton]

The mosfet is 18n65. I had to remove it to get the number.
There is no continuity between the center leg and both outer legs.
But there is continuity between both outer legs on the fet.

Resistor R52 (large resistor closest to blown cap) has a reading of 5.7k when removed from the board.

[budm]

I cannot see R52 on the top side of the board due to the picture is not clear enough to read the designators as printed on the board.
Show us good clear pictures of R52 and where it is located on the board. Source resistor should be < 1 Ohm.

"But there is continuity between both outer legs on the fet." What is the resistance reading using Ohm mode?

[budm]

https://www.badcaps.net/forum/attach...5&d=1594741646
What is the P/N of the SMPS IC U9?

[braxton]

I’ve attached a few more pics of the resistor I tested. Shown with yellow arrow from the top of board and purple x’s from the bottom. Yellow x’s and red arrow on bottom of board are the location of the blown cap.

It’s not possible to read anything on the top of u9 unfortunately.

[braxton]

Resistance reading on two outer pins of the fet is 1.4 ohms- same reading when I touch two leads of multimeter together.

[budm]

Originally Posted by braxton

Resistance reading on two outer pins of the fet is 1.4 ohms- same reading when I touch two leads of multimeter together.

Well that means you have shorts between Gate and Source, remove the that MOSFET and retest it off the board.
More than likely that U9 is damaged too.
What is the color bands of the R52?
BTW, you have have to try cleaning the top of IC with Alcohol to see if you can read the prints on top of it.

[braxton]

I tried gently scraping the coating off and using alcohol on the U9 chip but still could not read anything. At one point I thought I could read the number 28 but not sure.
Here is a picture of the resistor. The color bands appear to be brown-grey-silver-gold

[braxton]

Also, the mosfet was tested after removal from the board, and was shorted on the outer pins.

In the you tube video I posted in the first link, in the comments section, someone indicated they had a defective C30 (same blown cap) as well as a blown Q16 and D22 (close proximity to U9), but the latter two components don’t look blown on my board.

[braxton]

Its possible the U9 chip might have the following written on it:

28600D
96M
A6N2

[braxton]

would this be a suitable resistor replacement?

https://www.digikey.ca/en/products/d...mSeq=332340179

[braxton]

I salvaged a 0.22 ohm resistor, 417pF 2KV cap and a 12N60 fet from some scrap boards, and got the charger to come to life with the lights lighting up and no bangs or poofs of smoke.
Probably will not test further until I order the proper parts from digikey.

[budm]

Originally Posted by braxton

I tried gently scraping the coating off and using alcohol on the U9 chip but still could not read anything. At one point I thought I could read the number 28 but not sure.
Here is a picture of the resistor. The color bands appear to be brown-grey-silver-gold

0.18 Ohm (Brown/Grey/Silver)

[braxton]

Originally Posted by braxton

I salvaged a 0.22 ohm resistor, 417pF 2KV cap and a 12N60 fet from some scrap boards, and got the charger to come to life with the lights lighting up and no bangs or poofs of smoke.
Probably will not test further until I order the proper parts from digikey.

Well it's working fine and charging with my franken-parts installed.
I am debating whether I should even order replacements. I suspect the cap and resistor will be fine; less sure about the fet since its rated for 12A and 600V vs the original 18A 650V.

[braxton]

Thanks budm for helping me identify the parts that needed replacing.

[!sense]

I have the same issue and have noted similar damage to the same components.
I'd also like to pursue fixing it - should I continue on this thread to create a better repository of information on the Ego charger or would a new thread be better?