Logitech Z906 Service Manual Fixed Verified ((install)) ✦

The Logitech Z906 utilizes a powerful Switching Mode Power Supply (SMPS). The primary side of this power supply stores lethal voltages (up to 400V DC) inside its large electrolytic capacitors. before opening the chassis.

Over time, the massive electrolytic capacitors responsible for smoothing the DC voltage rails lose their capacitance due to constant thermal cycles inside the sealed subwoofer enclosure.

The Logitech Z906 is a THX-certified 5.1 surround sound speaker system, renowned for its 1000 Watts peak power (500 Watts RMS) and its ability to decode both Dolby Digital and DTS soundtracks. This makes it a popular choice for immersive home theater and PC gaming experiences. The system includes a powered subwoofer, four satellite speakers, a center channel, and a control console with an IR remote.

: Turn off the control console. Press and hold the Input button for 8 seconds. You should see several lights flash on the console.

Capacitors are a common point of failure in any aging electronics. Visually inspect the power supply board inside the subwoofer for:

The Ultimate Logitech Z906 Service Manual & Repair Guide: Fixed and Verified

Desolder the shorted MOSFETs. Replace them with identical, high-grade replacements (matching the voltage and amperage ratings exactly). Crucial: Always replace the thermal paste or silicone thermal pads behind the MOSFETs before screwing them back onto the heatsink to prevent immediate thermal failure. Fix 3: Clearing the Eprom / Factory Reset Method

The logic board inside the subwoofer drops the main DC rails down to 5V and 3.3V using linear or buck regulators to power the MCU and EEPROM chips.

Control up to 8 devices by this easy constructable remote control. It can work as a radio or infrared remote control, depending on the components. Each device output can be configured to be momentary (turned on while you press the button) or latched. Latched outputs can be toggled on/off by one button per channel, or turned on and off by two buttons per channel.

logitech z906 service manual fixed verified

Try it now, before building! Click on the transmitter buttons with the green labels on the left and see how the receiver outputs (K1-K8) change. Change the number of transmitter or receiver channels. Switch the receiver output type between latched and momentary.

Containing a PIC microcontroller, the circuit is very flexible. You can decide which receiver outputs are latched and which are momentary. The Manchester-coded transmitter output is well suited for the cheapest ASK radio modules or for infrared control. The units are configurable to a unique address, which must match to control the devices.

Related project: Learning remote control receiver
Take your existing remote control and control everything with it. This receiver can learn codes from an RC-5 format IR remote control, and associate the buttons to different channels and actions.

Related project: 2^16 remote control encoder and decoder
If you have TTL signals to control remote digital output lines, please check this project instead.

If you have trouble with programming PIC microcontrollers, you can consider builing other circuits based on Holtek HT-12D, HT-12E, Princeton PT2262, PT2272 and Motorola MC145026, MC145027, MC145028 encoders/decoders.

The difference between the 4-channel and the 8-channel version is only the software inside. The 8-channel transmitter has one button (S1-S8) per channel. The 4-channel transmitter uses S1-S4 buttons to turn on, S5-S8 buttons to turn off channel 1-4 (use with latched outputs on the receiver). The D1-D4 diodes and J1-J4 jumpers are optional, and are used to setup the transmitter address. Higher supply voltage results higher transmit power, but V+ range is 2-5.5VDC for the PIC MCU. When V+ is higher than 5VDC, use separate power for the mcu.

Configure & download
What if you can't get a pic16f630?

use a pic16f676
try a pic16f628, here is the modified transmitter

4/8-channel V4.2 infrared transmitter

infrared remote control transmitter schematic

The difference between the 4-channel and the 8-channel version is only the software inside. The 8-channel transmitter has one button (S1-S8) per channel. The 4-channel transmitter uses S1-S4 buttons to turn on, S5-S8 buttons to turn off channel 1-4 (use with latched outputs on the receiver). The D1-D4 diodes and J1-J4 jumpers are optional, and are used to setup the transmitter address. V+ supply voltage should be between 2.5-5.5VDC. It is practical to use two or three AAA batteries.

Configure & download

parts list

part	description
C1	100nF ceramic capacitor
C2	470 uF 6.3V, electrolytic capacitor
R1	10k resistor (1/8W)
R2	10 ohm resistor (1/4W)
D1-D4	1N4148 diode (optional)
D5	IR transmitter LED
Q1	BSS138 or similar N-MOSFET
S1-S8	tact switch, DTSM 61N or similar
IC1	PIC16F684 microcontroller, pre-programmed
B1	battery between 2-5.5VDC (CR2032, 3.6V LiIon battery or 3xAA batteries)

4/8-channel V4.2 radio receiver

The difference between the 4-channel and the 8-channel version is only the software inside. The 8-channel receiver outputs are individually configurable for latched or momentary output. The 4-channel receiver has two outputs per channel: K1-K4 are latched outputs, K5-K8 are momentary outputs for the four channels. The "valid" LED shows the transmitter activity. Make sure to turn on all address switches when the transmitter diodes are absent, or the J1-J4 jumpers are cut. Choose V+ supply voltage between +6-15VDC, based on the relay voltage ratings. For 6V relays, use +6VDC, for 12V relays use +12VDC.

please observe the corresponding address configuration!
transmitter: no diodes connected	receiver: switches all ON
transmitter: all diodes connected	receiver: switches all OFF

Configure & download

Zoom the picture
radio remote control receiver schematic

component pinouts

parts list

part	description
C1, C2	22pF ceramic capacitor
C3, C5	100nF ceramic capacitor
C6	10uF 6.3V electrolytic capacitor
CN1-CN8	PCB terminal block, 3-way (DG301)
D1-D8	1N4004 diode
IC1	PIC16F627 or PIC16F628 or PIC16F627A or PIC16F628A microcontroller, pre-programmed
IC2	LP2950CZ5.0 voltage regulator
LED	3mm LED (green)
LED1-LED8	3mm LED (red)
Q1-Q8	BS170 N-channel mosfet transistor
R1-R9	220R resistor (1/8W)
RL1-RL8	G5LE relay, see text for coil voltage selection
S1	piano DIP switch, 4-way
X1	4MHz HC49 crystal
RXMOD	3-pin radio receiver module, see text (hardware)

4/8-channel V4.2 infrared receiver

The difference between the 4-channel and the 8-channel version is only the software inside. The 8-channel receiver outputs are individually configurable for latched or momentary output. The 4-channel receiver has two outputs per channel: K1-K4 are latched outputs, K5-K8 are momentary outputs for the four channels. The "valid" LED shows the transmitter activity. Make sure to turn on all address jumpers when the transmitter diodes are absent, or the J1-J4 jumpers are cut. Choose V+ supply voltage between +6-15VDC, based on the relay voltage ratings. For 6V relays, use +6VDC, for 12V relays use +12VDC.

please observe the corresponding address configuration!
transmitter: no diodes connected	receiver: switches all ON
transmitter: all diodes connected	receiver: switches all OFF

Configure & download

Zoom the picture
infrared remote control receiver schematic

Over time, the massive electrolytic capacitors responsible for smoothing the DC voltage rails lose their capacitance due to constant thermal cycles inside the sealed subwoofer enclosure.

: Turn off the control console. Press and hold the Input button for 8 seconds. You should see several lights flash on the console.

Capacitors are a common point of failure in any aging electronics. Visually inspect the power supply board inside the subwoofer for:

The Ultimate Logitech Z906 Service Manual & Repair Guide: Fixed and Verified

The logic board inside the subwoofer drops the main DC rails down to 5V and 3.3V using linear or buck regulators to power the MCU and EEPROM chips.

hardware

The radio version circuit diagrams show generic ISM RF modules, which connect to the circuits using two power pins and one modulation pin. The transmitter (TX) module is connected to the transmitter circuit. The receiver (RX) module is connected to the receiver circuit. Choose ISM RF modules from the list of modules. The remote control works with the cheapest OOK/ASK modules and with FSK modules, too. Use the same frequency and modulation type for all modules. Choose a module which doesn't need setup - these are which connect only using 3 pins (ground (GND), power supply (VCC), modulation in/demod out (MOD) ) and usually have an external antenna (ANT) connection.

If you are building the infrared version, choose an IR LED matching the wavelength of the receiver module. The receiver center frequency should match the transmitter modulation frequency, which can be set the transmitter source (pwm_freq). If in doubt, just choose a TSOP1738. A list of usable modules: Sharp GP1U52X, IS1U60L, Vishay TSOP17XX, TSOP18XX.

FAQ

Q: Do I have to use a bs170 transistor in the receiver?
A: You can use other logic N-channel mosfets or npn bipolar transistors (with a series base resistor added) to drive the relays in place of Q1-Q8 of the remote control receiver. Examples: bss138, bc182+2.2kohm

Q: How do I set toggle or momentary mode for the relays?
A: Make a modification in the receiver source code. Modify the LATCH_MASK define - this contains one bit for every channel. A zero bit sets the corresponding output to momentary, a high bit sets the corresponding output to latched. For example, the line LATCH_MASK EQU B'00001111' sets channels 8-5 to momentary and channels 4-1 to latched (toggle) mode. Then use the compiler (MPLAB or gputils) to assemble the code.

Q: I want to control multiple outputs by pressing button 2 and 3 at the same time. Is that possible?
A: Not with this project. Please use this 2^16 remote control encoder and decoder instead.

Q: What if I can't get a pic16f630?
A1: Try a pic16f676, and put this line back into code:

clrf
0x91 ;
ANSEL

A2: Try a pic16f628, here is the modified transmitter

Q: What radio modules can this remote control work with?
A: You can choose from this list. The remote control works with the cheapest OOK/ASK modules and with FSK modules, too. Use the same frequency and modulation type for all modules. Choose a module which doesn't need setup - these are which connect only using 3 pins (ground (GND), power supply (VCC), modulation in/demod out (MOD) ) and usually have an external antenna (ANT) connection.

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Logitech Z906 Service Manual Fixed Verified ((install)) ✦

Logitech Z906 Service Manual Fixed Verified ((install)) ✦

4/8-channel V4.2 radio transmitter

4/8-channel V4.2 infrared transmitter

4/8-channel V4.2 radio receiver

4/8-channel V4.2 infrared receiver

hardware

FAQ

references