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 )
Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]
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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....
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Re: Power adapter from Apple Time Capsule - 0V at output
[B]sam_sam_sam[/B], no, there are nothing wrong there. It was just a bit dirty.
[B]Agent24[/B], 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...
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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...Last edited by andrey_ka; 03-22-2018, 01:20 PM.
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Re: Power adapter from Apple Time Capsule - 0V at output
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...
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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: [url]http://www.tablix.org/~avian/blog/archives/2009/11/this_time_multimeter_survived/[/url]Re: Power adapter from Apple Time Ca...tp://www.tabli
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Re: Power adapter from Apple Time Capsule - 0V at output
I replaced start up cap, but this not helped. So, all electrolytic caps are new at the moment.
Now, I think to look at PWM controller NCP1271AH, this is 65kHz PWM, I found datasheed for it (attached if someone in future will look for it). I bought old used simple oscilloscope (will arrive at weekend), so I can post more info after inspection with oscilloscope
If anybody have something to say - please post, I do further investigation at weekend and post results.
If anybody have...
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Re: Power adapter from Apple Time Capsule - 0V at output
I tried to measure voltage on start up cap, it changes between 5 and 15V, like on the video (scale on this video is 50V): [url]http://www.youtube.com/watch?v=aoSz1As3iI4[/url]
Also, I tried to heat up this cap, but this not help. I will replace it on weekend, when I'll be at radio-parts market.
P/N of SMPS IC U6: 1271AH PASM
Thanks)Re: Power adapter from Apple Time Ca...V, like on the
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Re: Power adapter from Apple Time Capsule - 0V at output
I have made good (good, not perfect) quality photos of board. Also, I added some comments. Attach them here.
As I understand, I need to try heat up small electrolytic cap (in red circle on my picture) during start up to see if the board will work under heating?...
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Re: Power adapter from Apple Time Capsule - 0V at output
Thanks all, yes, the output on the main filter cap is about 310 VDC (measured directly at the two legs of the cap).
The input is 220VAC, like in any country in Europe.
370forlife, is it possible to check main switching transistor, if I only have simple tester? I've heard this maybe FET transistor, so I afraid to damage it during testing.
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Power adapter from Apple Time Capsule - 0V at output
Hello! I'm not very experienced technician… Just trying to repair power adapter from Time Capsule. Maybe anybody have experience in these units?
This power adapter must output 5V and 12V. But now it outputs 0. I made full recap. Also, I checked voltage at output diode bridge - it's DC 220 V, so diode bridge is working.
I don't have scheme so I don't know what to check next… So I'm ask maybe anybody know what the most possible can be broken (if no capacitors) in such power adapters. Manufacturer - Flextronics.
Some photo attached. Thanks for any...
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