RC battery charger - Not sure where to start *HELP*

[gatewayhd2201]

Hi all,

Previously I managed to diagnose and fix a Gateway screen because of this forum and the good helpful people on here.

Now I'm faced with a new challenge and not sure where to start. Hoping I can find help again.

I have a Graupner SJ Polaron EX charger that is not working.

Back story: I bought the charger and tested it by connecting to 24v DC source (it works on 12v or 24v) it turned on and everything lit up, touch screen worked etc etc but I never tested it to charge a battery. Later on I sold it and shipped it out, the person who got it said it is not working and he shipped it back.
I think the guy connected it to higher voltage and burt something maybe? Are there any fuses or something else?

Now when I connect it to 24v power source it doesn't turn on, and the screen stays dark but there is a small red light that turns on that is next to the USB connector which weird enough works! I connected my phone and it charges out of that USB.

Any pointers on what to test or what to do?

Check out the attached pictures and let me know if I should provide more details or more pictures.

[ben7]

Re: RC battery charger - Not sure where to start *HELP*

Wow, looks like a nice charger!

I'd start out by testing the voltage going to the front panel, where the display is (and the control processor maybe?). Also check the voltage on that 3V coin cell battery.

[budm]

Re: RC battery charger - Not sure where to start *HELP*

There should be fuse/s and protection device incase of reverse polarity connection to the incoming DC power source or shorted circuit if this is a well designed unit.
The pictures are not clear enough for me to see. You should take good clear pictures of the whole board and also in sections.
I would look to see where the + incoming wire goes to.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

Thank you so much for taking the time to reply.

Pictures from every angle attached. Let me know if you need more pictures of a specific component.

budm, this charger is freakin expensive so Im hoping the least they could do is add some safety net like a fuse or something.

[stj]

Re: RC battery charger - Not sure where to start *HELP*

well the white object in the first pic with 5w on it is a fuseable resistor, so that needs to be checked.

[stj]

Re: RC battery charger - Not sure where to start *HELP*

third pic to left
what caused the soot marks on the heatsink?

[budm]

Re: RC battery charger - Not sure where to start *HELP*

That one looks like the load current sensor resistor, you can tell that it is closed to the output wires, but check it any way. I see the red B+incoming line soldered directly to the PCB but I do not see any fuse close by.

[stj]

Re: RC battery charger - Not sure where to start *HELP*

why is there a fucking great burn mark on the battery?!!!
pic number5

[kc8adu]

Re: RC battery charger - Not sure where to start *HELP*

sure you got your original unit back?
i see 3 terminal regulators on the daughterboard in one of your pics.
i suspect the logic "front end" is not getting power.start with the power to the front.
nice unit specs wise.
i still use my old tritons here.

[budm]

Re: RC battery charger - Not sure where to start *HELP*

Pic #7 does not show any burnt mark on the batteries, it looks like reflections of the wires.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

I can't find my multi-meter!!! AAHHHHH!!!! hahaha
I know I have it somewhere, so i'll report back very soon.

stj, that heat sink has some silicone and a white compound on the back so I think it's from that.

budm, the board seems to be mirrored near the output wires, white resistor, 2 caps, 1 copper wire coil thing, another big cap and a black resistor? the one numbered 3110-5260 what do you thin that is?

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

why is there a fucking great burn mark on the battery?!!!
pic number5

reflection!
believe me, I am the best in finding burnt marks, bulging caps, cracked stuff because I lack the academic knowledge but can spot things visually very well.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

sure you got your original unit back?
i see 3 terminal regulators on the daughterboard in one of your pics.
i suspect the logic "front end" is not getting power.start with the power to the front.
nice unit specs wise.
i still use my old tritons here.

yeah same unit. I take detailed pics from every angle so if my memory doesn't serve me, I reference the pics to make sure this is the unit I sent out.

I suspect it has something to do with the front too, because the small board with USB output works. I'll connect it to a power source and take a couple of pics...

the yellow thing is a mini helicopter charger, it charges fine through that USB

[selldoor]

Re: RC battery charger - Not sure where to start *HELP*

Is this model supposed to have a docking station? perhaps the power in fuse is in that?



http://www.electricrc.co.kr/src/prod...id=PolaronEX-W

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

No docking station, just a stand.
I found my shitty harbor freight multi-meter, now what setting should I use to test?

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

I turned the multi-meter to DCV 20 and touched the black and red wires showing in the picture below on the left, the small white connector which has only 2 wires red/black and no reading showed. Then I touched the black and red wires that are on the other bigger connector that has multiple wires and some numbers showed up on the multi-meter. I tested those because it looked like they are the wires connected directly to the front screen and the small white connector with only 2 wires seems to be the LED light power source.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

What someone on another site suggested and my findings.

The pictures are useful. I would start out by measuring voltages. Multimeter on the VDC 20V range, unit powered up.
There are three interesting areas: The connector to the LCD board and both upright boards left and right of the one with the USB output.
On the LCD board connector, measure the voltage from black to red and black to orange.
On the board with the small black heatsink, measure the voltage across any capacitor you can access without shorting out anything. Write down the voltage rating of the cap and the voltage you measured.
On the board with the two three-pin devices on the outside, measure the center pin against the two outer ones (for both devices) and write down the voltages.

My findings:
Black + red reads 3.07 - Black + Orange no change, stays at 0.01
2 caps on top read 0.3 - small cap on the right next to yellow cap reads 1 when on 20v (as if its an error) and reads 24.6 when on 200v. - 2 small caps bottom left meter doesn't change - yellow cap reads 1 at 20v (as if error) and reads 24.6 on 200v. - 3 pins on left red in the middle and black on left reads 3.37 and fluctuates to 3.38 and red in middle with black on right side reads 4.94 fluctuates to 4.95 - 3 pins on right side, red in middle and black on left reads 3.33 (steady) and red in middle black on right side reads 4.92 (steady)

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

third pic to left
what caused the soot marks on the heatsink?

Now I see what you are talking about, first I thought you meant the small heat sink on the small vertical board. I cannot figure out where that black came from, nothing around it looks burnt.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

Thanks to stj I took a closer look and found the part that is burnt. Do you think this can be fixed? How can I determine what is this part and where to get it from?
Check these pictures.

[gatewayhd2201]

Re: RC battery charger - Not sure where to start *HELP*

and a brighter picture
http://imgur.com/bpNhbd2