-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
820-3115 not turning on, PPVRTC_G3H and PP3V3_S5 jumping around
- Thread starter JohnB8812
- Start date
smiba
New member
How could the fuse short the power to ground? Think before you replace
Inject Amperage, more voltage will not help heat things up. Best to start at a low voltage like 1V and put the Amperage at 1A and start going up until you feel things starting heating up. Only increase the voltage if you can't inject more amps because the voltage limit is reached
I can not recommend putting the voltage at something high (>1.7V) in case its leaking away into a circuit that requires a lower voltage so you don't blow it up though
Last edited:
Ok gotcha guys. I have a Siglent supply just need to find good probes to solder on and inject voltage as the probes that came with it are kinda janky. Haven't gotten to do anything with board last few days because slammed with all the boring iPhone iPad and Mac repairs. We need a second tech to do that easy shit so I can focus solely on this stuff :/
Ok so stripped the wire for the crap probes we got so I could use them to inject voltage. I Solder red to ground black to PPBUS pad for the fuse. I start at one volt and one amp of power and nothing heats up but if I increase voltage it remains constant at 0.79 volts with one amp of power? Does that mean my power supply is messed up or is that bad?
smiba
New member
?? Red is usually positive and Black Negative
Did you just inject a negative amount of voltage? Not a lot of chips are going to like that.
How are your wires connected up?
0.79 volt @ 1Amp is alright. Your supply is not malfunctioning given that either your voltage is set at 0.79 OR your current limit is set at 1Amp.
If nothing is heating up you can increase the current limit until something is.
Last edited:
Ok yeah Smiba you’re right on the power supply I didn’t see the positivie and negative my probes were backwards. I will retry that again tomorrow lmao makes a lot more sense now. I figured it wasn’t the aupply because I can easily inject voltage into iPhones with the battery probes I have for them so that’s why I wondered if maybe I had had bad probes.
smiba
New member
Power will flow to the circuit in the wrong direction, polarized capacitors won't like this and a lot of diodes in IC's will mess up and possibly destroy parts of the IC.
Since you applied a current limit and the voltage was not very high you might have some luck but I woudn't be surprised some more things are broken now. Just try and see if we can solve it, this time with the polarity right.
Since you applied a current limit and the voltage was not very high you might have some luck but I woudn't be surprised some more things are broken now. Just try and see if we can solve it, this time with the polarity right.
smiba
New member
Doesn't sound too unlogical, the System is in S5 and on a really low voltage so most ICs aren't even working.
The charging light is still there so hope is not all lost.
Just for the sake of clarity, While just running the board from the charger right now. What is the voltage of PPVRTC_G3H, PPBUS_G3H, PP3V3_S5, PP5V_S5?
The charging light is still there so hope is not all lost.
Just for the sake of clarity, While just running the board from the charger right now. What is the voltage of PPVRTC_G3H, PPBUS_G3H, PP3V3_S5, PP5V_S5?
Yeah the customer actually has purchased a new computer from us, so he’s all set. I think I’m gonna use this as a donor (for whatever is still good on it) just because I think you’re right it’s gonna be a nightmare at this point. I appreciate all your guys’s help with this one learned a TON from this board as this is is the first I’ve ever had with no power like that I’ve only had sensor issue Macs, no backlight Macs and easy JTAG removal ones so this was definitely my first true challenge repair. Next time, I’m just gonna have to be a little more careful with a problem like this, but I definitely think this one will help for the long term.