GTV LD ZASL6W-30 LED power supply

Small (up to 6W) LED power supply, 12V/0.5A

Repair:

• C5 (47u/25V) was replaced as it completely lost it properties, not even being recognized by component tester as capacitor
• THX203H needed replacing

As this exact model costs $5, repairing it might be not worth the time. I thought this only capacitor failure at first, but driver chip was available at the local electronics store that I had to visit anyway for $0.75.

I'm not 100% sure if I've fixed everything as this power supply behaves somehow weird - it's output voltage is stable with 100 Ohm load (120 mA) but falls down to 9 V with 27 Ohm load (~300 mA).

Asus VW223D monitor repair

 This is 22" 16:10 (1680x1050) LCD monitor from 2008. It has CCFL backlight (4 tubes), so power consumption is rather high (55W according to user manual). I suspect this might be power consumption with maximum brightness, as in my test it heats up only a little. While I'll probably won't keep it, I like warm colors of this kind of monitors comparing them to LED/blueish cheap LED-backlight panels.

Disassembly: panel is screwed up to back part, front frame is held by one screw and latches.

Only VGA input

Realtek RTD2554VH

Delta DAC-19M020 power supply, used also in other monitors. Apparently still available (as used products, so it might be hard to predict their expected life time) on aliexpress for less than $10.

When I've tried to turn it on, it only was blinking shortly in regular intervals - pretty typical sign of power supply malfunction or overloading. It turned out to be typical failure, with 2200u/10V capacitors visibly bulging and losing capacity. Other capacitors seemed to be fine when measuring with tester, but I've actually replaced all electrolytic capacitors except for the high voltage one. 

Other problem: not working ON/OFF microswitch (probably because it was the most used one). Metal part soldering was broken and also its latches were streched, so it was only loosely attached. I probably could search for some replacement, but soldering back microswitch metal part and securing it with some epoxy was faster and seems good enough.

Trust Mauro USB headset

Trust Mauro (17591) USB headset, retail price ~$20.

Problem: weird sounds from left earpiece (not correlated with played audio), slightly disturbed sound from right earpiece.

Rather big in size in-line controller: volume, output mute, microphone mute.

Sound card (chip with scrapped markings) inside USB plug. Plug itself is glued together but can be opened by prying (with some damage).

Cause of the problem: mismatched connections between USB part and controller part. I think this was factory error, probably partially caused by not so clear PCB markings (for example there is "M-" and "M/-" contact pad).

Build quality is worse than with Trust Roha - headband is thin and little creaky, ear cushions are less soft. In-line controller is large and its weight can be felt when e.g. it drops from the table.
Probably too much bass (same as Trust Roha), but not as muddy - they sound better than Trust Roha.

On the other side microphone is quite noisy. It seems that this noise depends little on USB connection - it was higher when I was using extension cord.

One weird thing is that sound card emits some heat - not a lot, but this is still unusual for this type of device. I'm not sure if this is not a problem of my particular item, but otherwise it seems to work correctly.

Trust Roha 24188 USB headset

Inexpensive USB headset with microphone.

Fault: no sound from left earpiece, intermittent sound from right earpiece.

Earpiece disassembly: two plastic pieces are press-fit together with ear cup held in between. No glue is used.

Volume control + mic mute on the cable.

Sound card / electronic plug is held inside USB plug.

Fault: broken cable between controller on the cable and headset, possibly in more than one place. I've had to cut off about half of the cable from the headset side.

Overall build quality seems quite nice, with stable cushioned headband and pleasant ear cups.

Sound quality coming from headphones is somehow muddy and little unnatural, but might be acceptable.

Microphone might be little quiet but in general should work.

Logitech MX Master 2S

Logitech MX Master 2S with mechanically broken right mouse button.

This mouse can be paired with up to 3 receivers, either Unifying or Bluetooth. According to specification Bluetooth LE is required for second option.

Internal Li-Ion accumulator, charged with micro USB.

Two visible T5 screws and four Philips screws hidden under feet. Hooks on left and bottom sides, but easy to open.

"Hidden PCB" for button hidden in thumb reast.

500 mAh battery. Three leds with light pipes on left side indicate charge level. Operation time on single charge is specified as 70 days. Swappable (short instruction is included by manufacturer, though T5 Torx screws are not exactly user friendly) and and as it is not crammed can be probably swapped for third party higher capacity cell.

Very weird: there was extra screw stuck under battery holder screw. I don't think this was the cause of failure though as there seems to be extra space in this area. I'm pretty sure no one opened it before, so it must be manufacturing fault.

nRF 51802 - from Nordic site: general purpose, ultra-low power SoC ideally suited for Bluetooth® Low Energy and 2.4 GHz proprietary wireless applications. It is built around the 32-bit ARM® Cortex™-M0 CPU with 256 KB flash + 16 KB RAM. The flexible 2.4 GHz radio supports Bluetooth Low Energy and 2.4 GHz proprietary protocols, such as Gazell.

It incorporates a rich selection of analog and digital peripherals that can interact directly without CPU intervention through the Programmable Peripheral Interconnect (PPI) system. Flexible GPIOs enables you to connect digital interfaces like SPI Master/slave, TWI Master and UART to any of the 31 GPIOs on the device.

The nRF51802 is a low cost variant of the nRF51822, it has the same functionality, but has minor performance degradation in terms of:

• 2 dB less RX sensitivity
• Slightly higher RX and TX peak currents

BQ24040 LiIon charger

Pixart PMW3816DM sensor. Up to 4000 dpi according to specification and working on glass surfaces.

Motor has semicircular element on the shaft. After rotating it other plastic element is moved and mouse wheel is either freed or is resisting.

Broken right mouse button. I've used some epoxy glue and also heated this element with hot air (at 130 C) to adjust its shape/position.

There is also missing metal spring from the same button (probably lost at the same time button was broken). This changes the click feel, but still seems acceptable.

Hidden button (described as intended for gestures):

After repair: