Noco GB70 torch/.flashlight repair - Page 1
Forum section: electronics / repair

author: BarnacleNZ
author_rank: Newbie
timestamp: August 08, 2025, 11:18:08 am
content: Hello all,Yesterday I opened the GB70 to replace the 30A Aux fuse. After reassembling, all was fine, except the torch no longer functions. The GB70 seems to think its on, but no light.I pulled it apart again, and probed around - now i'm no electronics expert, but i can usually bumble my way through.It appears to me there are 2 halves, or 2 separate LED driver circuits to drive 4No. LEDs each. When i put it into a 'led flashing' state, i was able to measure an on/off pattern from the transistors or whatever they may be. It was around the 2.7V if i recall correctly, but i'm unable to get any output to the LEDs.Fairly certain all the capacitors and resistors are fine.What else should i be checking?I have made sure the solder to the LED board is good.I'm happy to open it again this evening and get some photos.Thank you!

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 08, 2025, 01:55:45 pm
content: Good Morning BarnacleNZ, The NOCO GB70 ismainlya jump-starter for 12v vehicle batteries. Besides the light, do the charging ports for 12V and USB devices, work. The elephant in the room is the 30 amp fuse that you replaced...: do you know how it blew? If it is only the light that doesn't work, check if power is getting to the LEDs, which would determine if they are now defective. Those are my guesses.Please come back and tell us your results. Thanks.

author: Kean
author_rank: Unknown
timestamp: August 08, 2025, 03:18:26 pm
content: As BILLPOD mentioned, this it not a torch but a jump starter battery pack.It is important to provide that kind of information when asking for help. You shouldn't expect or rely on others to search for details on the product.I think some photos will definitely be needed as I don't think there will be many internal photos online, or if anyone here has the same jump starter.

author: jerryk
author_rank: Regular Contributor
timestamp: August 09, 2025, 05:47:10 am
content: When the unit is off if you press the light switch does the unit turn on with no leds lit? Typically the light switch will both latch the unit into the on state and activate the two front leds in a solid on state.Jerry

author: jerryk
author_rank: Regular Contributor
timestamp: August 10, 2025, 09:46:07 pm
content: Did you give up? Fix it?In case you are still in the fix it mode, I dug out one of my working GB70 boards to show where you might want to explore. Look at Q13 and the diode and resistors in that circuit. When you engage the flashlight button you should hear a click of the relay on the back of the board. It's driven by the Q13 which is an SS8050 npn transistor. It engages the relay coil and passes 12V to the front led's. Since the main fuse you replaced is on the downstream side of the relay output pins, I suspect your issue may be in this area.Just note of caution. Before you go and replace anything in this circuit you should note the close proximity in your 12V and 3.3V power rails. To accidentally feed 12V into the 3.3V side of the board will most likely kill your MCU. I typically unplug all plugs and unsolder the battery ground so there is no power on the board before doing any replacement work. I also included a screen shot of the LED current driver XN2115 just for reference.Jerry