ZoltriXound PC speakers

Cheap PC speakers from ancient times.

2W, 4Ohm speakers, magnetically shielded

601M marking
By the date on the plastic it looks like speakers were made in 2002.

EPC-S601M310
881015 VER 1.0

Transformer: ETS-S2BO9021
230V/9V, 0.2A

Idle voltage from transformer is close to 12V RMS, after rectifying ~15.4V and dropping by ~1V when playing. Transformer is heating quite a bit.

SP2822 amplifier (most likely equivalent of TDA2822M)

 Amplifier should be able to provide few hundreds mW per channel, although it seems to be working outside of specified voltage / load impedance range.

Apparently soldering wires on copper side was faster / cheaper.

470u for power supply filtering,
220u at output

Zelmer Z28Z010 iron repair

Zelmer is Polish brand with long tradition, although these days its production is probably in China like for everyone else.

 Most tricky part of disassembling for me was screw hidden under hard to remove (thigh latches) "extra steam"/sprinkler buttons.

 And this is what failed - thermal fuse MICROTEMP G4A00 240C, 10amps, 4mm diameter. Connected to wires with crimps, put in silicone tube and held by metal plate at heating element.

I'm assuming that bimetal thermal regulator is working fine and thermal fuse just tripped prematurely. Its characteristics says that it must trip at 240C, it must hold (holding temperature or Th) at 200C but it is also susceptible to aging so over time it might fail at lower temperature.
I've bought replacement (5pcs described as NEC Microtemp SF240E) on ebay for 1.49USD including shipping and reused original crimps.

Nady 49 MINI wireless microphone/receiver set

Wireless microphone + receiver set from 1989.

 49HT-01 REV.A

 NE571N - dual channel compressor/expander

 NE5534 - well known low-noise opamp (single)

 MC1458 - dual opamp

 CA3089 - IF amplifier and FM detector

Vakoss TM-421UR mouse

 It looks like PCB was initially designed for A2636 but A2639B (pin-compatible successor) is used. This is all-in-one mouse SoC from Apexone with optical sensor (800/1200cpi), USB + PS/2, voltage regulators, internal oscillator. Detailed datasheet is available.

Date on the silkscreen: 2008.09.08, model: JY-62.