Noco GB70 Jump Pack Repair

[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]

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..

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... 

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]

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.

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.

[jerryk]

Check Q14.  That is what I think is the transistor that drives the relays thru R74 from pin 11 on the MC.

Edit: FYI all of these NOCO boards are VCC 3.3V.

Jerry

[eurgenca]

Daughter board is a board behind led module board and there is u313, if I remember correctly, and in 70% is fried if you connect 24v. You will see this when you try to charge bat.

P.s. Did you check boost switch. Noco use shitty components and I replace a lot of SW on this booster.

[jerryk]

As far as the switches go I would replace all three regardless of their operating condition.  I agree with @eurgenca that they are crap switches and it's a common failure of these NOCO jump packs.  The easiest method for switch removal is to snip them off at the legs and then remove the remainder with solder braid.

Good Luck.
 
Jerry

[demon1300]

Check Q14.  That is what I think is the transistor that drives the relays thru R74 from pin 11 on the MC.

Edit: FYI all of these NOCO boards are VCC 3.3V.

Jerry

I've checked Q14 and if i supply a voltage there, the relays turn on and i get 12V at the clamps.  I back probed through the resistors and it looks to go back to pin 9 on the Holtek HT50F2E microprocessor.  I managed to get my Noco GB70 pack back from a friend (slightly older version) and pulled it apart to so some further testing...

Different style main IC, much larger and appears to connect to the pin you're referring to.

So on this broken unit, i don't get the 3V output on pin 9 to drive the relays when putting the unit in boost mode like i do with the older unit.  I think I've found the smoking gun.  Funny thing was, i did go through this circuit earlier - I just didn't measure the voltage on that output when in boost mode  lol, live and learn i guess.

So i'd say i've got a dud microcontroller...  I've tried searching for that specific model, however looks like Noco must have this thing made specifically as i there is literally zero info on it anywhere.

Does anyone have a trashed pack that could maybe help me out here by supplying this IC?

Regards,

Rob

[jerryk]

If your MC is shot the pack should not power up at all.  No LED's, or partial working events will occur.  That's because it has to latch the 3.3V LDO (IC6 labeled 7553-3) to it's on state.  I would confirm that the output pin on IC6 is at 3.3V and not 3V or 2.9V.  If it's output is being pulled down you have a short or load somewhere.  The MC label is just a Holtek OEM number that applies to one of their existing MC's.  The older GB70's were HT46R067 which is an OTP MC.

I would keep hunting but use caution.  You still have your main 12V power wires connected and that is very dangerous if you are removing components to test things.  For the heck of it check the four R005 resistors.  If you can, hook up a battery to the main clamps and see it the relays come alive.  Check all of your components around Q14 and Q15 for correct function. Then trace all three of the active wires in the relay connection at main board.

Edit to add:  Also sniff around IC2 comparator circuit for faults.  As I recall this is involved in the detection scheme of the voltage of the battery to be jumped.

Good Luck - Jerry

[demon1300]

If your MC is shot the pack should not power up at all.  No LED's, or partial working events will occur.  That's because it has to latch the 3.3V LDO (IC6 labeled 7553-3) to it's on state.  I would confirm that the output pin on IC6 is at 3.3V and not 3V or 2.9V.  If it's output is being pulled down you have a short or load somewhere.  The MC label is just a Holtek OEM number that applies to one of their existing MC's.  The older GB70's were HT46R067 which is an OTP MC.

I would keep hunting but use caution.  You still have your main 12V power wires connected and that is very dangerous if you are removing components to test things.  For the heck of it check the four R005 resistors.  If you can, hook up a battery to the main clamps and see it the relays come alive.  Check all of your components around Q14 and Q15 for correct function. Then trace all three of the active wires in the relay connection at main board.

Edit to add:  Also sniff around IC2 comparator circuit for faults.  As I recall this is involved in the detection scheme of the voltage of the battery to be jumped.

Good Luck - Jerry

Thanks for the continued suggestions Jerry!

I've just checked IC6 and it's got 3.28v so that seems fine to me.

Using that MC data sheet that you gave me has definitely highlighted the problem.  Pin 11 (PD1) which appears to drive the relay circuit has a short to ground (Pin 5 VSS).  This clearly means there is a dodgy component in this circuit somewhere, i just can't seem to find it!

Tracing pin 11 back, it goes through 5 capacitors then to the boost switch.  From there it looks to go over to R79.  I've only tested this resistor in circuit, and get quite a different reading from the other GB70 i have here.  On the good pack, it's reading around 563k ohm compared to 235k ohm.  It looks to be marked with 1004 so am assuming 1m ohm?  Not sure if this too far out of spec to be an issue?

The other issue i've found is that one of the pins on Q14 appears to have continuity to R74 (marked in blue on the diagram).  The good pack i have does not have continuity here.  I'd removed these components to see if there was anything wrong here and it looks like the problem remains.  Does that maybe mean the board is toasted on an internal layer?

Multiple issues here, i'm just not experienced enough to seem to be able to connect the dots!!

[jerryk]

The blue dot in your photo should only have continuity with PD1, pin 11 and that's it.  I'm not aware of any internal layers on the GB70.  The board I have is two sided but a bit older than yours.  Since you have removed the only possible offending components (R74 and Q14) that I'm aware of there is a chance that you just might have an internal short in your MC.  I haven't seen a partial MC failure in these Holteks but I suppose it's possible.  Sure hope not.  You can check Q15 for short's and diode check pins 2 and 3 but the short to ground at PD1 is not a good sign.

Jerry