Here are old pictures of fixing “dE” door error on Samsung WF0600NXW washing machine by replace door interlock . Here You can see closeups and part number, after replace and assembly in revers order – working perfect.

Today I decide to make firmware (ROM) update, after finishing and restarting Android i get information about “Invalid IMEI”.

When my heart start beating again i start looking out for solution then develop many attempts to address the problem.

RT4 is unpopular phone, so there virtually none information.

Lucky chipset inside phone is compatible with Xiaomi solution and that software i used.

1. open Your phone, and on back label You have IMEI numbers for two sim cards – write them down.
2. using windows computer install https://allmobitools.com/downloading-maui-meta-3g-4g-imei-repair-tool/
   
   
3. after install open application using administrator privilege
   on right side click “reconnect”  remove battery and unplug usb cable,  install battery, plug usb cable there should be beep of plugging in usb device, after while You should see something like this:
   
4. from drop down menu on the left select “IMEI DOWNLOAD” and in new window click button “IMEI UPLOAD FROM FLASH”
   They should appear two tabs SIM1 SIM2
   You need to enter Your IMEI form point 1
   last digit is checksum so don’t enter it, it will be calculated automatically, if it match then You are good to go and can click “Download to flash”

After successfully write, click disconnect and restart phone, it should work properly 🙂

I miss that old good times when You could just replace cells in battery to make it fully working again 🙁

Here are pictures of me testing Smart-UPS made by APC model APC 750 before replacement of batteries.

On oscilloscope i check true sine wave while working on battery (while testing on a power supply).

As You can see there is a beauty-full sine wave!

There are also visible connections in case You have that ups without battery.

Some random UPS APC simple repair job – no DC charging – failed capacitor, after replace working perfect.

They are very old photo and i don’t remember what king of model it was…

Here are pictures of weirdest repair job i had…

I had not working FDD midi drive, after opening i found EPROM not properly fitted inside socket…

They are hard to pull out and enclosure was sealed so nobody tampered it…

I can’t imagine how much “G Force”  should be apply to lift that ic from socked… of course enclosure don’t show any sights of shock / drop.

After pressing it down, everything start working correctly…

Finally i got replacement backup capacitor.

After soldering new cap and testing problem was solved,  clock can be unplugged and after powering back time is still counting.

From some time, my great Philips Wake-up Light start suffering from resetting clock time after short power loss.  I remember that some time ago, when unplugged in power loss occurred after power back clock time was continued. It clear indicate problem with backup battery. I decide to open and investigate.

Inside i found not a single use backup battery but capacitor. Over time it’s lost capacity.

I do not have spare so decided to order new one from bay.

Continuation

This soldering is not a proper way – terminal should be crimped, but i don’t have crimping tool for that size so i use this solder pot as work around!.

2000W inverter in ideal condition at 12V should take about 2000W/12V = 166A but to be safe, have low voltage drop and make sure it will work at 10V (2000W/10V = 200A)  + efficiency i decide to use 35mm2 copper cable.

The cheapest cable I found was a “welding negative ground cable” it was much more cheaper than cable dedicated to car audio amplifiers 🙂

Just make sure to mark red “positive end” 🙂