IIYAMA E2274HDS (PLE2274HDS-B2) monitor

I've got this monitor for free as previous owner gave up on fixing it.
Symptoms: monitor works fine at first look, but after hour or so it may randomly turn off or start showing image with weird colors (e.g. missing one color entirely). OSD menu has often random minor artifacts. It cannot be turned on again using ON/OFF button but with powered off entirely (detaching power cable) for few minutes it starts working correctly again for a random time. Sometimes image might get really weird:

 From the posts on few forums this is common issue with this model and also with larger XB2374HDS and E2475HDS / B2475HDS. Two possible problems are listed: failure of NOVATEK NT68677UMFG chip (scaler) and failure of serial EEPROM (A25L020). Some suggested that main chips are just faulty and need replacement, but my plan for now is just trying to lower it temperature using radiator from old Pentium 4 motherboard north bridge. After testing for a few days this radiator seems to be helping, not fixing all problems (like not powering on after signal going down and then up) but reducing them significantly (hours of work but still need to cut down the power once or twice per day) - this might be just coincidental.

 PAM8007 - class D power amplifier, 2 x 1.5W @ 4Ohm, 10% THD, 5V supply.

 Audio quality is very poor as nothing separates the front and the back of the speaker. Perhaps some piece of plastic is missing from this unit? Otherwise this would be just poor design - sacrificing audio quality for like a dollar.

Monitor is using PWM for brightness control - it is working with 240Hz frequency right after brightness is reduced below 100%.

 I've changed scaler chip for new one (from 2016) bought on ebay for ~$4. Although I've used hot air old one was rather hard to desolder. Also, despite used some protecting aluminum foil I've blown away 2 or 3 0402 SMD components near the chip - be careful when setting air flow.
Replacing scaler did not seem to make difference - monitor is still randomly shuts off, so my next planned step is replacing Flash chip. I have now new chip soldered and I've added piece of 3M thermal tape and small radiator just in case, but I think replacing Novatek was not necessary.
Update: Pm25LD020 finally arrived ($1.50 for 5 pieces) and then I realized I have no programmer for these low voltage chips (pickit2 with flashrom did not work for me), so I also ordered CH341A-based flash programmer ($2.50).
After desoldering original A25L020 I wasn't able to read anything making sense from it - it is possible I have overheated it, but I've used firmware from https://www.elektroda.pl/rtvforum/viewtopic.php?p=15640144#15640144 (iiyama ple 2274hds-b2 25l020.bin) and it seems to work. For programming I was using CH341A.
I don't see any problems with monitor at the moment.
This seems to be frequent problem with this model, but if you have to spend money to fix it keep in mind that this is not top of the line device - vertical viewing angles are pretty poor, PWM frequency is low (240Hz), speakers are just disgusting.

 LED driver: OZ9998BGN, controlling 4 LED strings, up to 160mA per string, external PWM dimming input. My guess is that PWM frequency is controlled by scaler firmware thus might be not possible to change.

(low quality schematic comes directly from datasheet)

 LD7576AGR - power supply controller

 SMK0965 - N-channel MOSFET, 650V, 9A.

 SP1060 - dual Schottky diode, 60V, 5A per leg

APM8005 - dual N-channel MOSFET, near LED driver chip

Grundig Music 51 radio

Small portable FM PLL radio with clock and alarm - RP 5201 PLL. Retail price: ~$25-$30.

 2 R6 cells for clock / station memory backup (optional), 4 R14 cells or 230V AC for full operation.

 Decent speaker.

 Two keyboard boards connected with single wire pair each - reading keys by measuring resistance.

 This one is incomplete - transformer is missing, otherwise it works fine. Mains socket is couples with mechanical switch disabling internal battery.

Power supply filtering is very impressive for this class of products - there are 3 coils, 2200uF + 1000uF + 2 x 470uF + 6x 220uF + 100uF (one of these might be DC decoupling for speaker actually).
Audio amplifier: "CHMC S75"/"D820"

Microcontroller: TMP86FM29LUG. Toshiba, 8-bit TLCS-870/C series, 32kB FLASH, 1.5kB RAM, 10bit x 8ch ADC, built-in LCD driver, dual clock. Supply current 4.5mA typ, 8-20uA in SLOW/SLEEP modes. UART bootloader.

 Coils on small board resembling hybrid circuit.

 Radio chip.

Both reception and audio quality is pretty decent.
It's worth noting that apart from 2xAA clock/station backup it seems to retain memory with energy from capacitors for a minute or so.
NiMH cells (1.2V) seems to work fine, so semi-discharged primary cells would work also. Consumed current = 6uA.

UB-PB228 powerbank

Small powerbank with single 18650 cell. Branded as "URBAN BEATZ".

 5V/1A input and output, 2200mAh capacity - matches markings on LiIon cell.

 Small mounting screws are covered with sticker front.

 TP4213 from Shenzhen TPOWER Semiconductor. Chinese datasheet exists - 1A max, over-temperature protection, overcharge and over-discharge protection, output over-voltage protection, output overload protection, output short-circuit protection.
Preset 4.2V / 4.35V charge voltage with accuracy of ± 1%.
When charging, LED1 flashes (1Hz?), LED1 is always on when the battery is fully charged, LED2 is always on when discharging, LED2 is flashing when discharging low.
LED2 1Hz flashing = low battery. 

 2200 mAh 18650 cell, SZN = Shenzhen?

PCB markings: EC018_v6.1 2014.6.4

I've received this in non-working condition - it was not holding any charge at all. Few sources suggested resetting CID with screwdriver and although using this cell further might be risky it worked. Cell voltage jumped to 4.09V so CID probably "exploded" during charging.

$0.99 mini flashlight

Small $0.99 flashlight from ebay.

 Single LED.

 ON/OFF switch at the back. It might be weakest point of this flashlight - it clicks nicely but light gets wobbly if it is touched when powered on. Because of this rubber cap flashlight has also some problems with standing on its back.

 This works with single 18650 AA cell - I've tested it Eneloop (as I have few of them laying around anyway).

 While this flashlight is often advertised as "3W" it consumes roughly 0.2A from 1.3V Eneloop (260mW).

Emitted light is cold. I don't have point of reference but given the small flashlight size (it can be hidden completely in hand) output light stream is satisfying - it's good enough for the trip to basement or to be used as emergency light in bathroom.

As problem with the switch was getting annoying it was time to dismantle it, which turned out to be pretty straightforward, starting from rubber cap:

Switch itself does not seem to be serviceable, but I washed it for an hour in isopropyl alcohol and then I've poured drop of synthetic oil (popular FINISH LINE green bike chain lubricant) inside - so far this is working.

Another issue (after few years of sporadic use): it seems like "+" cell contact is also not reliable and it might turn off whan shaken. Some cleaning helped, I've also put piece of paper inside to make the cell bounce less, but I'm not sure if this would be permanent solution.

Car USB adapter

 Car USB adapter- 12..24V DC input, 5V/1.5A output with mini USB cable.

 NEC B772P (2SB772) transistor, 34063 switching regulator from ON Semiconductors.