ElectronicNoobBlog

I’v got myself a TRI PRC 152 replica and i’m trying to put real military issued u-283/u connector, but i have to figure out what kind od PCB connector is used between TRI board and that connector.

The answer is: PicoBlade Molex Mini Micro JST 5pin 1.25mm

and could be bought without any problems on RC stores.

Here are some pictures.

From couple of months my hotair station start loosing suction power (and hotair airflow) and yesterday it stop working what was very dangerous because hotair heating element got red hot.

I started repair from checking “pump” module, but after checking outtake hose i found good airflow.  – most expensive part is working fine.

I found clog in airflow-meter showed on pictures caused by “flux”.

I fill airflow-meter with isopropyl alcohol overnight and next day all flux was dissolved, just rinse with more isopropyl alcohol and station working like charm 🙂

Very simple but useful fix, recommend check Your station and clean before it clog.

Couple months ago i had problem with SHARP LCD TV LC-32DH66E  that won’t turn on.

Symptoms: power up was slow, and getting slower over time until stop won’t turn on (green led)

TV have inside build in self-test that should show source of problem by blinking led in pattern described in service manual.

Unlucky problem is, failed capacitor don’t trigger this error warning.

Fix is very simple, replace showed capacitor – i decide to use other form factor so hope it won’t come back again.

6800pF 6.8nF

To access capacitor You have flip board back, it’s under PSU control IC.

Originally it have BR2032 battery with spot welded tabs – it’s quite hard to get in normal price so i have use “glue wire” to stick tabs onto battery.

Do not use soldering iron – because heat will damage battery.

If You don’t have spot welder – glue wire – is great for low current application – like in this scenario!

Couple months ago i got myself used AKG T912 headphones.  They can be used with regular battery or rechargeable.

Question is how whey prevent from recharge a single use battery when someone stuff it inside.

Answer is a third contact for recharge touching body of battery.

To be able use rechargeable battery, it need to have striped part of battery body to allow third pin contact – and then be recharge.

So if You fit rechargeable battery inside AKG T912 and they not charge – check for contact to body.

On pictures bellow You can see how it works.

Today i got broken li-ion Bosch PSR Select screwdriver.

Repair was very easy, access to battery (common 18650) great.

Less than 5 minutes and tool work like new.

Tip: Always when You come across dead li-ion battery inside any rechargeable device always:

1. measure current drawn from battery when device not in use (failed battery might be caused by failed component on PCB drawing constant small current so for example after 3 days Your new battery will go bad again) – so this is very important step
2. measure charge cut-off voltage – plug charger and make sure it not go over 4.2V on battery terminals – failed charging circuitry might also cause battery fail – and broke new battery after couple of charges

I got keyboard to fix with strange symptom, pressing space delete last entered character… acting like pressing backspace key…

Very strange, very unusual but after opening case, i easy found what’s wrong… there is jumper that allow you to select action of space key… just replace jumper and will work ok.

Here are some pictures of this unusual job.

My heating element in soldering station WEP 968DB+ finally fail.

I got replacement and go for this simple repair.

1)

First is check if heating element is failed (check resistance between red leads from heater – my read infinity what’s mean fail open).

2) Mount new heating element

3) When i first run soldering station displayed temperature was 300*C and real temperature was almost 400*C so i need to calibrate it.

I was thinking it’s a MCU controlled station so i tried pushing + – temperature buttons, powering on / off while pressing buttons but i was unable to enter calibration from front panel… after opening i found that calibration is done by multi turn potentiometer…

Calibration pot is blue one, close to soldering iron switch (and side) opposite will be probably or hotair heater.

Tips while calibration:

– Avoid cleaning / apply lot solder just before measurement – when You do this You lower temperature of tip and station will send more power to make constant temperature and You will get higher temperature that will drop in seconds giving false positive high.

– Avoid testing just before plugging in – it send more power while starting and temperature will be false high – will drop later

– Try to calibrate as close to Your working point temperature (if You work at 315*C calibrate to 315*C) not for 200*C. The fare You will go from calibrated temp there will be more difference!

Here are some pictures from job.

I’v got my old hairclippers made by Philips but they suffering short work time… sometimes i had go over wire.

I decide give them a try to fix.

It turn’s out that model of Philips hairclippers was quite easy to open without damage enclosure after putting everything back.

I feed it by the best (in my opinion) possible of shelf battery NiMh Eneloop.

Here are some pictures of that simple repair: