Panasonic RQ-SX5V — проблема отключения «ухудшайзеров» звука (S-XBS / Train / ASC / Live) без пульта

Panasonic RQ-SX5V Cassette Player: I received a sample with a pre-activated bass boost mode (S-XBS), which degrades the sound with modern headphones. It can only be disabled with the original remote, which is not included. 🎧 Panasonic RQ-SX5V (November 1994). S-series cassette player with a built-in FM/AM/TV tuner. Based on the RQ-SX5, this model was one of the first Panasonic models since the RQ-S60V to combine a tuner with an LCD remote control. The control buttons and main unit display are located on the rear of the unit. Built on a deru mechanism, this allowed for a compact body and a built-in tuner—a solution previously considered too complex for similar models. Supports: • Metal tape playback • Auto-reverse • Search for up to 3 tracks • Blank Skip • Dolby B NR • Vibration Sound • FM/AM/TV tuner • Wired remote control with LCD display Power — Gumstick battery or 1 x AA battery. Specifications: • 78.5 x 109.2 x 24.7 mm • Approx. 193 g • Approx. 8 hours of operation • 3-band FM/AM/TV tuner Starting price — open. 00:00 Welcome. Presentation of the very rare Panasonic RQ-SX5V cassette player. 00:44 Several problems arose while restoring the player: The radio does not work; The enhanced bass mode (S-XBS) is pre-selected. 1:23 I had a similar problem with the RQ-SX22V. 2:01 S-XBS is easily disabled with the original remote control, but I don't have one. 2:26 Theory. Suggestions for disabling S-XBS by shorting a special contact. I need a wiring diagram for the RQ-SX5V. 3:03 The closest player for which a service manual is available is the RQ-SX22V. 3:39 How is S-XBS mode activated in hardware? Pin 41 of the audio amplifier chip is responsible for boosting low frequencies. 4:52 How is Train EQ (ASC) mode activated? 6:02 Equalization modes for the RQ-SX22V (RQ-SX5V) are controlled via the TC9317F microcontroller. 7:35 Unlike the RQ-SX22V, the RQ-SX5V also has a Live EQ mode. I'll take a closer look at how to activate this mode, using the RQ-SX3 model as an example. 11:00 I'm having doubts about the correct way to disable the equalization modes. 11:49 The Vibration Sound mode should also activate S-XBS. 12:19 How else can I deactivate previously enabled equalization modes? Why isn't the previously enabled S-XBS mode reset when the power is turned off? 13:00 A special feature of the RQ-SX22V and RQ-SX5V models is the presence of an AK93C45LF non-volatile memory chip. 13:22 It's possible that the equalization modes are stored in non-volatile memory. This means you need to disable the DO memory pin—then the TC9317F microcontroller won't be able to read data and will start in default modes. 14:22 The RQ-SX22V and RQ-SX5V players also have a separate chip that controls the tape transport mechanism. 15:16 Interfering with the non-volatile memory shouldn't affect cassette playback, but it will prevent you from saving radio settings. 15:56 Practice. To safely unsolder the DO memory pin, I recommend covering the surrounding area with Kapton tape. 5:00 PM The radio settings are indeed not saved, but the sound has improved significantly—the excess bass has disappeared. 5:53 PM Description of an experiment involving connecting the DO memory pin in the hopes that the default settings from the microcontroller will be written to the memory. 6:47 PM Voltage measurements on pin 41 of the audio amplifier showed that the S-XBS returned to the "on" position. 7:35 PM I finally unsoldered the DO memory pin and checked that the equalization modes were disabled. 8:45 PM Radio stations and regional settings will not be saved. 💬If you have questions about the portable cassette player or want to share your experience, write to the Telegram chatbot - https://t.me/walkman_chatbot. You can read about the experience of listening to cassettes on different players here: https://t.me/walkmanfans Secrets On restoring cassette players and more: https://t.me/walkmaland And a great thread on common problems with cassette players of different models is here: https://stereo2go.com/forums/threads/... EN 💬If you have questions about cassette portables or want to share your experience, message the Telegram chatbot - https://t.me/walkman_chatbot Tips and secrets for restoring cassette players and more: https://t.me/walkmaland And a great thread on common Walkman issues across models: https://stereo2go.com/forums/threads/...