A first-person, immersive day in the life of an appliance repairman

An appliance repairman’s day: Edifier C3100 speaker with mains hum — going by experience, the middle amp chip (TDA2032 type, imported) is replaced, thermal paste and touch-up soldering, every channel fine; a kids’ Chinese-classics story player with a broken USB port gets a new one, charging at 0.7A 3.8W; the cell was starved flat and must not go below 3V (30A power cell); a Midea handheld vacuum gets a new battery, powered up and tested, perfectly fixed

First job: what looks like an ELEX (Edifier) C3100 speaker with mains hum from one speaker, which means a shorted amp chip, so straight in; going by experience the middle amp chip is the problem; swap it (2032) and the hum is gone; pull the two originals, BDI, imported; thermal paste on, fit the amp chips and touch up the solder; power up and test, big brand at a low price, no buzzing; input signal, left and right channels OK, sound from both sides, rich deep bass, play a post-80s DJ favourite. Second job, a Chinese-classics story player with a broken USB port, replace it; charging current 0.7A, 3.8W; the cell has been starved flat, it must not drop below 3V, 30A power cell discharging at 3.8(V); ‘Welcome’; full charge 2.6 (reading), enough to beat Dahuanma (joke), all good. Third job, a Midea handheld vacuum, battery replaced (no commentary), powered up and tested, perfectly fixed, put on charge. Comments: Edifier speaker (creator: yes); swapped mine for an LM1875T, the TDA2030 is retired; which one is the voltage-select wire; assorted repair requests (water dispenser, freezer, range hood); he has every part going.

Outcome

Steps5 steps · click a frame to jump

1. 
   1. C3100 speaker hum → shorted amp chip; swap the middle one by experience

   An ELEX C3100 with mains hum from one speaker, which means a shorted amp chip, open it up; the middle amp chip is the problem, going by experience; swap in a 2032 and the hum is gone; pull the two originals.

   00:04 – 00:36
2. 
   2. Imported amp chips + thermal paste, touch-up solder and test, all channels OK

   BDI, imported; thermal paste on; fit the amp chips and touch up the solder; power on, no buzzing; input signal, left and right channels OK; sound from both sides; rich deep bass; post-80s DJ.

   00:45 – 01:50
3. 
   3. Story player with a broken USB port gets a new one; charging 0.7A 3.8W

   The Chinese-classics story player’s USB port is broken, replace it; charging current 0.7 amps, 3.8 watts.

   01:39 – 02:30
4. 
   4. Cell starved flat (must not go below 3V), 30A power cell; revived

   It’s starved flat, must not go below 3 volts; 30A power cell discharging at 3.8, see that; ‘Welcome’; full charge 2.6 (reading); all good, no problem.

   02:35 – 03:12
5. 
   5. Midea handheld vacuum battery swap, powered up and tested, perfectly fixed

   Midea handheld vacuum; battery replaced (no commentary); power up and test; perfectly fixed, put it on charge.

   03:09 – 04:03

Bill of materials

Measured on camera

Creator’s tips

• Hum from one side is usually a shorted amp chip; by experience, swap the middle one first 00:04
• When replacing amp chips, apply thermal paste and touch up the solder 00:45
• Lithium cells must not go below 3V or they starve flat 02:35

Pitfalls

• A starved-flat cell needs reviving or replacing 02:35

Li-ion safety

Quotes