Sony STR-DE445
Sony 5.0 amplituner from 2000 or 2001. Quick specifications:
- 5 x 60W at 1kHz, 8Ohms, 0.7% THD; I'm guessing this is peak/music power, not RMS as total power consumption is specified as 160W
- 10 Hz - 50 kHz + 0.5/–2 dB (with sound field, tone, and bass boost bypassed)
- S/N for analog inputs: 96 dB (A, 250mV)
- S/N for digital inputs: 100 dB
- FM sensitivity, mono: 18.3 dBf, 2.2 µV/75 ohms, stereo: 38.3 dBf, 22.5µV/75 ohms
Initial issues:
- almost no FM radio reception - tuning occasionally to one or two strongest stations, but with mains hum stronger than actual useful signal; audio from Line IN sounds file
- operating erratically - some buttons not registered or registered as completely different function
- minor mechanical damage that I probably won't be able to fix without a donor
Lots of dust inside.
MITSUMI tuner, 340844 / 0818MY. LA1837 + LC72131. Controlled by digital serial interface, outputting already decoded L/R audio signal.
These PCB colors are awful - hard to read if there is any dust.
Digital input board. AK4527VQ codec, CXD9511AQ DTS decoder, LC89055W digital audio receiver, IDT71256 SRAM.
Standby power supply.
These semi-white switches are awful. Every one has either high/unstable resistance when turned on, sometimes zero reaction.
I've tried to put some alcohol on them and I've also soaked three of them after desoldering for a few hours. All of them (35 or so) would need to be replaced.
The blue ones (4 of them) are fine.
The cause of not working tuner: inadequate tuner supply voltage, caused by completely dried C899 (100u/35V Elna).
Service manual for this model is easy to find, though some parts like block diagram are confusing (transformer shorted by D899 diode below):
Replaced capacitors, most of them completely lost capacitance:
- C899 100u/35V ELNA
- C603 100u/10V Jamicon
- C753 100u/10V Jamicon
- C653 100u/10V Jamicon
- C703 100u/10V Jamicon
- C808 100u/10V Jamicon (just high ESR)
- C896 47u/16V Jamicon (just high ESR)
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