Power adapter from Apple Time Capsule - 0V at output

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V at output

tom66,
Apple uses Rubycon, Samxon, and 1 pcs CapXon as a startup cap. I lost unsoldered caps somewhere in house… but I found foto of Time Capsule PSU in internet: http://www.tablix.org/~avian/blog/ar...eter_survived/

[tom66]

Re: Power adapter from Apple Time Capsule - 0V at output

Ah, my error, so those are replacements?
Still, I think a single CapXon is bad. SamXon is maybe OK.

[SM-Piyes90]

Re: Power adapter from Apple Time Capsule - 0V at output

Ah, my error, so those are replacements?
Still, I think a single CapXon is bad. SamXon is maybe OK.

Lol , personnaly i guess every cap brand ending with XON is bad

So andrey , did you manage to check that PWM ic , am in a similar case as you btw .

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V at output

Lol , personnaly i guess every cap brand ending with XON is bad

So andrey , did you manage to check that PWM ic , am in a similar case as you btw .

No, I just bought used oscilloscope, but when I tried to remove dust inside it, and short circuit something, it burned with smoke

Now, I'm finishing to fix it, PSU of oscilloscope is now works, will connect it to channel boards. Very good compact oscilloscope (see picture), but its age like mine )

So, this topic is not forgotten, I just don't have enough time. But I hope soon I'll have some measurements and oscillograms from Time Capsule PSU, and update this topic with new info. Thanks all who watching )

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V output, UPD: 5V/12V only in idle mode

So, sorry for my prolonged absence, had no time for this project. But now I switched back to it Long story short:

1. Found a short-circuited smd cap on time capsule mother board, in power line. I just apply 5V DC current and saw area with active heating up. Just removed that small cap and now I have working TC motherboard. Better than nothing!

2. Power adapter is in semi-working state now. What I've done - checked ALL passive elements like electrolytic caps, resistors and diodes. And found 2 smd resistors near main MOSFET, which was breaked (see attached picture). I don't know what they do, but they need to have very small resistance - 0.2 and 0.3 Ohm. I replaced it to new, and unit started up and gave out 5V and 12V! But when I connect load, voltage drops to 0 again. So, at the moment, power adapter works only in idle mode.

Сontinue to investigate...

[sam_sam_sam]

Re: Power adapter from Apple Time Capsule - 0V at output

What is the problem with the joint next to ( R3 ——>the lettering on the board )<—— at the same end of C6 ) in the photo it does not look right is because of the light hitting the board or is that a bad solder joint

[Agent24]

Re: Power adapter from Apple Time Capsule - 0V at output

Going by the layout of the board, they look like current-sense resistors for the switching MOSFET.

If they went open then the rest of the current sense circuitry would probably have seen the primary voltage, and something else there could have blown. Check all the other resistors connected to the ones which were failed.

Can you trace back the current sense circuitry? Where does it go?

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V at output

sam_sam_sam, no, there are nothing wrong there. It was just a bit dirty.

Agent24, for your question "Can you trace back the current sense circuitry? Where does it go?" -- No, it hard for me. Some of the board coated with rubber, and I don't see where conductor comes. This rubber very hard to clean out. But I'll try.

Today, I desoldered main MOSFET and checked it with multimeter (in diode mode). I noticed, when MOSFET is open, it's n-channel is not 100% conductive. Voltage drop at open n-channel is 1700mV in one direction and 330 in other. While any new other MOSFET shows 0/0 in open mode. So, I decided MOSFET became faulty and need to be replaced. The bad news, Apple uses the same parts you can find on the market, but mark them by unusual codes.

This MOSFET was marked as BL0NK60Z (or BLONK60Z?) and you never find datasheed for it in google. See photo attached. So, I just desoldered other MOSFET from China-copy MacBook power adapter - 20N60C3 (data sheet attached) and put in place of Apple-proprietary MOSFET.

But still unsuccessful. Power adapter give out 5 and 12V in idle mode, when connect load, voltage drops to 0. I checked also two Shottky rectifiers, they seems to be ok.

Will keep you informed )

[Agent24]

Re: Power adapter from Apple Time Capsule - 0V at output

MOSFET is not relabelled with custom code, it is just B10NK60Z not BL0NK60Z. Sometimes they use very confusing fonts!

How is the power supply for the controller IC when the supply is loaded vs unloaded? Does it stay steady or fluctuate?

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V at output

Today, I decided to check optocouplers (OC). I found simple schematic, which allow to quick test OC, needed just 2 LEDs and 3V battery. See attached picture.

I found, that in one OC 2nd LED shines a bit less than first, while in second it shines too dimly. So, I'll replace OC to new one tomorrow, and after that will check power supply for the controller IC.

[andrey_ka]

Re: Power adapter from Apple Time Capsule - 0V at output

Something went wrong with my PSU... I replaced optocouplers to tested new ones, and PSU became completely dead. Tried to change optocouplers to old, or to other new ones, but without success. So, I'll start from beginning )