2018-07-16

Zelmer Z28Z010 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.

2018-07-14

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




2018-07-07

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.

2018-06-23

Nokia 105

Severely abused Nokia 105

 TA-1034






 Whole keyboard is backlighted with single LED with polycarbonate light guide.
 Display: T177F455FPC VER08

2018-05-27

Eurit 133 ISDN/DECT base station


 No screws, easy to open with flat screwdriver
 Gold-plated PCB, no screws and very nice build quality.


SC14425 from National Semiconductors - Complete Baseband processor for DECT Base Stations with Caller-id and Handsfree
 TDA7052B - 1W audio amplifier with DC volume control
 Infineon PSB2186N - ISDN 2B+D interface
 Two radio antennas