ElectronicNoobBlog

Recently i’m working to fix PHILIPS SCE7640/12 Laptop 19V 2000mAh power bank.

I’v got from there 3 2000mAh fully operational Li-Poly batteries :)))) (one of them was bad)

So i’m was looking in my lab, for some use for them… then i notice my USB Power bank… it should have 12000 mAh capacity…. i open and check… Yyea… around 3000mAh  real capacity (3V discharge) divide by four batteries mean 750mAh per cell !!!.

I found that 3 x Li-Poly batteries will fit inside this power bank…

I discharge them, stack in parallel and have 3.7V at 6000mAh capacity (declared when new).

After doing measurement, i got 5560mAh of real capacity 🙂 – Not bad

I added fore safety measure  – NC thermal switch witch i got from other notebook battery.

It was really good job, because i double capacity and lose some weight!

Here are pictures from fixing.

Good job! 🙂

Have You trying to repair device witch blow fuses ?

Recently I was fixing a power supply witch shorted rectifier bridge and then i was using series light bulb trick to let me try find cause of short and prevent blowing fuses in my lab and melting traces on PCB. Then i just solder bulb into fuse holder.

Few days ago i got a computer PSU to fix, and he’s also blowing fuse in my lab, so i decided to use light bulb trick again, but  this time i build more usable device for this and future uses.

So what’s series light bulb trick in few words.

You are putting for example 100W light bulb in series with Your device.

Light bulb will act like resistor and allow to pass only 100W to device (full brightness) and let You actually see how “short” looks,  for example is it solid or blinking when transistors get switched on.

If Your device is working and took for example 50W, (You put 100W bulb in tester) when using light bulb trick You should get 50% of brightness, if  took 25W You should see just glowing etc.

If device is fully shorted always 100% brightness.

You can put different bulbs 20W 40W (etc) to make Your check diagnose more accurate.

For example when You put a switching wall plug PSU to 20W bulb, it should for few seconds glow bright (charging capacitors) then goes dark or amber…. if not  and it’s lighting ( full brightness – that should be a short)  for example 50%…  you possible have shorted output or input filter capacitors and they adding fiction load to Your PSU. Bad output filter capacitors may also be spotted by hot psu without any load.

Here are some pictures from building and seeing “in action”.

Make sure You put PHASE wire by bulb, this will show You light also when You will be shorted to ground not only neutral wire!

Play witch 230V is dangerous, if You don’t know what are you doing! DO NOT FOLLOW this tutorial and stay safe witch low voltage circuits !

I spend few Years witch low voltage circuits before feel confident to start fixing high voltage sections! 

!Notice, PSU show short also when switch is turn to OFF!

I notice that my illuminated  rocker switch in power strip stop working…

It might look stupid, but actually it is really helpful, just one look and i know that power is exiting in outlet.

Unscrewing power strip is impossible due to non usable screws.

I actually found that switch is just pushed (just need pry with flat screwdriver) into case, and leads are long enough to re-solder new one without opening case.

Here are some pictures from “repair” ( to be fancy i ordered from china green one 🙂 )

Success! 🙂

Hello all ElectronicNoobBlog viewers,

Few day’s ago i got a 9V 7A very old (198x) years switching PSU.

It was “thrown away” because it was blowing fuse inside PSU and in power installation – so short was very massive:).

First after opening i spot swollen filter capacitor at 220V side.

I removed that filter cap (both) and replace with new one, then put new fuse in PSU and connect into power…

Bam! blown… fuses in lab goes off.

Fuse was very dark, so it’s mean massive short and lot’s of current passing.

To confirm, i soldered in place of FUSE 120W lamp and try again. Lamp was glow at full brightness with little flickering.

I started from checking rectifier diodes, and found one shorted.

I don’t have same type, so i replace all four  with higher current and voltage.

It was little tight but still looks pretty.

Power again, lamp glow very very little in 1 second (when charging capacitors) and goes off.

After confirming output voltage i remove lamp, put fuse and put everything back for 24H test. – Work perfect!

Here are pictures from repair. You can spot “shorted” diode on meter (i measure working for contrast).

Do You have cordless phone (or tv remote) with few not working keys? or maybe You have buttons to press very hard to get them working? Let’s fix it now before You get crazy and smash your device :-).

In this example You need Alcohol (isopropyl) min 99,5% pure (to not leave any pollution after drying) DO NOT USE SALICYLIC ALCOHOL it will leave white “powder” – salycil!

Cotton pads

Pry tool and screwdriver

I have opened my phone and clean PCB contact’s witch alcohol, next i clean rubber (carbon) contacts pads.

After cleaning i put all back together.

As You can see all keys working perfect.

Hello, ElectronicNoobBlog viewers!

Today i’v got for You pictures from fixing my Logitech MX mouse.

So at first thing, Logitech MX is really really great and i won’t change it for any other mouse!.

Recently i start having problems with “double click” issue, sometimes when i press LMB its start selecting text, so when i want click at something it’s selecting text…  it’s start to be very annoying so i decide to fix it 🙂

I was suspecting what’s problem, so i grab a similar “cheap” also Logitech mouse for spare parts, they have same type of “switches” made by OMRON. I found there is way to buy on ebay from china only same switches but if i have broken mouse for parts so why spend money if i can grab one from free.

Here are pictures from operation, removing from old mouse and soldering back into MX mouse. I also do a “hot steam” cleanup of  “roller” module, and now mouse looks and work as new one. Some pictures might look stupid, but i made them to make sure i’ll be able to look at them and put my mouse back together in case i forgot something.

I don’t post any tutorial, i was doing this first time in my life. To open mouse i use only my common sense 🙂

Recently I got (from Hong Kong) replacement for my Sony DSC WX9 display (LCD) because original get’s cracked.  Look, they put “Sony” logo at frame , it Look’s like original!

Here are some pictures form repair ( I don’t record video because that was my camera witch i’m using for make video:) second it was my first time when i was doing lcd replacement in digital camera so it took long  and i was using only my common sense. So there are no educational point in looking at me trying to open it :). But as You can see  i done it successful-y :>

Working perfect!

Yesterday i had to replace SCART socket soldered to PCB.

That many pins looks very creepy to desolder but i’m being lucky and from around half year i’m owner of ZD-915 “china made :)” desoldering station.

I’v got idea to make movie from it, to let You guys see how useful this device is in real situation.

I could do this faster, but camera on tripod was blocking my movement 🙂

Some pictures

About month ago i found that my car cigarette lighter USB charger stop working…

After investigation and measuring voltages on output i found that problem is not in charger circuitry but in USB socket itself.

That charger was worth about 1 USD…  but is it worth to repair?

I open charger, and check ebay (china sellers) to found same type USB socket.

I found 🙂 1 USD / 10 pcs with shipping included! I bought and pack all charger parts into ziploc bag for future repair.

After waiting time of 1 month , today my pack of 10 USB sockets arrived and i could start “repair”.

As You can see on last picture, my phone is very happy being charged 🙂

Repair took about 5 minutes

My conclusion:

I could order new one for 1 USD and put old to trash but instead of throwing out this 1 USD i got  10pcs USB sockets. I use one of this and i have 9 left in my “lab” for future experiments and of course working charger. 🙂 As You can see, sometimes it’s worth to fix something cheap 🙂