| Electronics > Repair |
| Noco GB70 Jump Pack Repair |
| (1/4) > >> |
| demon1300:
Hey Guys, Really need some help! I'm still a bit of a noob when it comes to fully understanding complex electrical circuits. I have repaired a bunch of my own equipment before, blown caps, diodes etc.. This GB70 jump pack from Noco appears to be getting a bit beyond my capability and figured i'd see if i can get some help to try and diagnose what's still wrong with it. Backstory: It was plugged accidentally into a truck cigarette lighter socket to charge the unit which happened to be 24V instead of 12... The unit shut off immediately and wouldn't power on at all, only the light/torch would turn on. I really want to get this fixed as it's not mine (a close friends) and it's literally brand new... Current state: I've disassembled the unit and managed to track down 2 x zener diodes that were short to ground and also another diode that was also short. Replacing these components has now brought the unit 90% back to life! - It powers on - the torch works - I have a 5v supply out from the USB's - I have 12v supply out from the other barrel connector Unfortunately the issues arose when trying to use the 'boost' function or just simply jumping a battery without boost enabled. I don't get 12v on the clamps when boost is enabled which i should as it over-rides the polarity and voltage low protections of the device. It's basically a manual override to just have 12v supplied. It lights up as if it's in boost mode, however no relays activate sending power to the clamps. I've tested (at least to my current skill set) a bunch more components that look to feed this area of the circuit and i can't find anything weird. There are a bunch of IC's however and am not sure how i should really be testing these without a circuit diagram. I also can't get my head around the relay wiring on these units... They run them via a 4 pin connector with 3 wires populated from the mainboard. 30 appears wired to the neg clamp. 87 appears wired to the main lipo negative 85 and 86 are labelled "REL-ON" and "BAT-" respectively I have continuity from 87 to both 85 and 86 which is odd to me. If i power the relays manually with external power, they appear to click and activate as they should when hitting the boost option, but don't. Anyone worked on one of these things before or could possibly assist with some advise on what to check next? I have basic tools (hako station, fluke multi, power supply etc.) and would be happy to get more shots or provide some readings if needed. Really appreciate your help on this one! Apologies for shot quality I can get some better ones if required during the day! |
| ener_dk:
Hi, What I would do first is to check if there is vcc on the IC's, usually its 5v but please check with a datasheet for one of the IC's on the mainboard. If the is no 5v just double check a couple more ICs, if still no 5v you proberly have a powersupply problem - look there for your problem. I know you have 5v for the USB ports but I would check it anyway just to be sure that the rest of the board have the expected supply voltages. Then with my none experince with jumper starters would I check the 3 wires going from the relay board to the "mainboard" and see why the relay are not contacting. (BAT/REL_ON/CB) Use datasheets for the IC as they usually have design examples for the delevopers and thats gives us a good guide for how the circuit works -- hopes this makes sense for you. Hope this helps you.. |
| demon1300:
--- Quote from: ener_dk on February 13, 2024, 09:25:27 pm ---Hi, What I would do first is to check if there is vcc on the IC's, usually its 5v but please check with a datasheet for one of the IC's on the mainboard. If the is no 5v just double check a couple more ICs, if still no 5v you proberly have a powersupply problem - look there for your problem. I know you have 5v for the USB ports but I would check it anyway just to be sure that the rest of the board have the expected supply voltages. Then with my none experince with jumper starters would I check the 3 wires going from the relay board to the "mainboard" and see why the relay are not contacting. (BAT/REL_ON/CB) Use datasheets for the IC as they usually have design examples for the delevopers and thats gives us a good guide for how the circuit works -- hopes this makes sense for you. Hope this helps you.. --- End quote --- Thanks for the advice. I've checked most of the IC's and they all appear to have VCC as they should. Problem is that most of them in the data sheets accept from 3v all the way up to 30v or so which makes it hard to know what they should be getting fed. I believe i've also found another dead component, which i need some help identifying. I'd say it's either an PNP or NPN transistor but am completely stumped when it comes to it's value. It only has the marking "WP" as per photo which doesn't appear very helpful. There doesn't appear to be any others with the same marking on the board... :palm: It's testing as open on all legs, regardless of polarity. Figured it should be reading something in diode test mode on the multi meter. I've also taken a pic of the board and marked out where the continuity goes for this component to try and help someone understand the circuit and what it may be. I've also marked the voltages on the pins when the device is turned on. Anyone got any ideas on what this may be? |
| eurgenca:
Hi. Could be BCR192L3? Check on daughter board 5 pin smd with markings A08G, usually get fried if 24v is applied. Can check on monday if q31 is really PNP transistor. |
| demon1300:
--- Quote from: eurgenca on February 25, 2024, 08:05:40 am ---Hi. Could be BCR192L3? Check on daughter board 5 pin smd with markings A08G, usually get fried if 24v is applied. Can check on monday if q31 is really PNP transistor. --- End quote --- That would be awesome if you could check! I have another GB70 here which is a slightly older version, so doesn't have this same circuitry. When you state daughter board, what exactly are you referring to? The PCB is dual sided and populated on both sides. The only other board is attached to battery and there is only 2 relays on it, nothing else. |
| Navigation |
| Message Index |
| Next page |