Apologies for the long radio silence. New job etc.



Thank you for the information. Unfortunately, after removing the croocked cap, there is no change in boot behaviour. No Apple logo etc. But all ICs do heat up, like before. The A10 chip get very warm within seconds, the U8100 gets warm.

How can I indentify what the power rails to the U8100 are? I do not have access to boardview schematics (can't find any), only block diagrams. If I can manage using those, what and how would I have to look for? Again, this is my first repair attempt at this level, so I'll...

Resistance to any random ground point, as measured from the positive battery terminal on the PCB side, is about 2.3M Ohm.

I finally was able to take some time to look at this board again. A week ago, I used the "flux smoke" test for finding overheating components, as I don't have a thermal camera. I could not find anything though. Cleaned up afterwards with IPA.

Today I checked all inductors marked L. I also checked if their solderjoints may have come loose, which wasn't the case. I've found a similar post, in which measuring the caps was recommended ([URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/105014-ipad-7-a2197-no-power"]this...

Resistance to any random ground point, as measured from the positive battery terminal on the PCB side, is about 2.3M Ohm....

That was my first thought as well, based on initial research on this behaviour.
Thanks, I will check these components. If I manage to identify them correctly using the diagram, that is.

Apologies for the late reply, I was on holiday.

The current draw to 480mA is immediate. As is the drop down to 20 mA after a while....

Bump

Yeah sorry, 1kHz. Tired when I wrote it and am dealing with a different repair where ground resistance value was needed. I'll correct it to avoid confusion.

Thanks for the information. I was expecting that kind of answer. Was just wondering if it was indicative of a known or common issue, like some products do have. For example, AFAIK, the CD player on these Wave products can be quite problematic.
But I guess your recommendation, based on your experience, is a starting point. Thanks.​...

Dear reader

I have been asked to check out a faulty Bose Wave system belonging to a relative. The faulty unit produces loud intermittent pops and crackles. Sometimes there is speaker audio output (FM/AM, CD etc.), most of the time there isn't. This behaviour degraded over time fairly quickly, to the current situation where no sound is put out at all. Gently messing and wiggling wires, connectors or heatsink has no effect in force-replicating the problem. I have little experience in audio repair when it comes to (main)board electronic component faults. Bose repair WAS about 140$ (most...

Dear reader

[B]TL;DR: iPad not turning on, A10 and power IC become (very) warm when attempted to turn on but this power-on cycle has a 'cooldown' period wherein powering on doesn't work, does not take more than 0.5A charge.[/B]

I am working on an iPad 7th generation 2197 from >2019 with no / limited charging and no boot issues. It is a refurbished purchase made in 2021. It appears the 'refurbish' company has either done prior motherboard work (all protective component shield layers are gone) or is one of the many trash refurbish companies (little screen adhesive left,...

Re: Recapping Sony ICF-SW55 - verifying cap values

Back again. I have already ordered the parts and performing the repair. I have, however, stumbled upon a few exposed traces and one broken trace path (all a result of damage by leaking cap acid), so it's a bit more work than I had anticipated.

Anyway, a few days ago I found a new source, one I hadn't found before, listing a more complete service manual than found on elektrotanya and radiomuseum etc.
[url]https://www.petervis.com/manuals/sony-icf-sw55/icf-sw55.html[/url]
Thanks to this upload I was able...

Dear reader

I am performing a repair on a Sony ICF-SW55, which includes recapping (some) of the SMD capacitors on the mainboard. I am looking for verification of their values. At the moment, I'm 95% sure I've got the right values, but it is hard to find some official, credible or multiple independant sources on this.

At the moment, I have selected replacements based on the following list of values:

3 x 470uF 10VDC
3 x 4.7uF 35VDC
4 x 47uF 50VDC
8 x 22uF 6.3 VDC
1 x 220uF 6.3VDC
5 x 100uF 6.3VDC

Which...

Re: New Members - please post your introductions here

Hi.

I joined initially to be able to download some schematics for a motherboard repair, but figured it would also come in handy for other the occasional electronic and consumer products repair stuff.

Kind regards