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Behringer DEQ2496 Mastering Processor

Bootscreen
Bootscreen

I was recently given this unit, along with another Behringer sound processor to repair, as the units were both displaying booting problems. This first one is a rather swish Mastering Processor, which has many features I’ll leave to Behringer to explain šŸ˜‰

Input Board & Relays
Input Board & Relays

All the inputs are on the back of this 19″ rackmount bit of kit, nothing much on this PCB other than the connectors & a couple of switching relays.

Main Processor PCB
Main Processor PCB

All the magic is done on the main processor PCB, which is host to 3 Analog Devices DSP processors:

ADSP-BF531 BlackFin DSP. This one is probably handling most of the audio processing, as it’s the most powerful DSP onboard at 600Mhz. There’s a ROM on board above this for the firmware & a single RAM chip. On the right are a pair of ADSP-21065Ā  DSP processors at a lower clock rate of 66MHz. To the left is some glue logic to interface the user controls & dot-matrix LCD.

PSU Module
PSU Module

The PSU in this unit is a pretty standard looking SMPS, with some extra noise filtering & shielding. The main transformer is underneath the mu-metal shield in the centre of the board.

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eBay Flyback High Voltage PSU

Flyback PSU
Flyback PSU

I have found myself needing some more in the way of High Voltage supplies of late, with the acquisition of the new He-Ne laser tubes, so I went trawling eBay for something that would be suitable to run these tubes. (I currently only have a single He-Ne laser PSU brick, and they’re notoriously hard to find & rather expensive).
This supply is rated at 1kV-10kV output, at 35W power level. Unfortunately this supply isn’t capable of sustaining the discharge in a large He-Ne tube, the impedance of the supply is far too high. Still, it’s useful for other experiments.
The flyback-type transformer clearly isn’t a surplus device from CRT manufacture, as there are very few pins on the bottom, and none of them connect to the primary side. The primary is separately wound on the open leg of the ferrite core.

Drive Electronics
Drive Electronics

The drive electronics are pretty simple, there’s a controller IC (with the number scrubbed off – guessing it’s either a 556 dual timer or a SMPS controller), a pair of FDP8N50NZ MOSFETs driving the centre-tapped primary winding.
The drive MOSFETs aren’t anything special in this case: they’re rated at 500v 8A, 850mĪ© on resistance. This high resistance does make them get rather hot even with no load on the output, so for high power use forced-air cooling from a fan would definitely be required.

Test Setup
Test Setup

Here’s the supply on test, I’ve got the scope probes connected to the gate resistors of the drive MOSFETs.

Waveforms
Waveforms

On the scope the primary switching waveforms can be seen. The FETs operate in push-pull mode, there’s a bit of a ring on the waveform, but they’re pretty nice square waves otherwise.

Arc
Arc

At maximum power on 12v input, about 25mm of gap is possible with an arc.

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Sky+ HD Set Top Box

Sky Box
Sky Box

Time for another teardown! I managed to fish this Sky+ box out of a skip, but to protect the guilty, all serial numbers have been removed.
These are pretty smart devices, with DVR capability on board.

Ports 1
Ports 1

There’s a lot of ports on these units, from RS-232 serial, POTS modem, eSATA, HDMI, USB, Ethernet, SCART, Optical, digital outputs & even composite video.

Ports 2
Ports 2
Ports 3
Ports 3
Top Panel
Top Panel

Removing the top plastic cover reveals the operation buttons & the built in WiFi adaptor, which is USB connected to the main logic board.

Front Panel
Front Panel

The PCB on the front of the chassis has all the indicators, and the IR Receiver for the remote.

Cover Removed
Cover Removed

Removing the top shield of the chassis reveals the innards. The PSU is on the top right, 500GB SATA disk drive in the bottom centre. The main logic PCB is top centre.

Logic PCB
Logic PCB

Here’s the main logic PCB. The massive heatsink in the middle is cooling the main SoC, below.

SoC
SoC

The main SoC in this unit is a Broadcom BCM7335 HD PVR Satellite System-On-Chip. It’s surrounded by it’s boot flash, a Spansion GL512P10FFCR1 512Mbit NOR device. It’s also got some DRAM around the left edge.

Smart Card Reader
Smart Card Reader

The smart card reader is on the PSU PCB, the controller here is an NXP TDA8024

PSU PCB
PSU PCB

The PSU itself is a pretty standard SMPS, so I won’t go too far into that particular bit. The logic PCB attaches to the large pin header on the left of the PSU, some of the analogue video outputs are also on this board.
There’s also a Microchip PIC16F726 microcontroller on this PCB, next to the pin header. Judging by the PCB traces, this handles everything on the user control panel.

Power Supplies
Power Supplies

Some local supplies are provided on the logic board for the main SoC, the IC in the centre here is an Allegro A92 DC-DC converter. I didn’t manage to find a datasheet for this one.

LNB Front End
LNB Front End

The RF front end for the satellite input is a Broadcom BCM3445 Low Noise Amplifier & Splitter, again not much info on this one.

RS232 Section
RS232 Section

The standard MAX232 is used for the serial interface. I imagine this is for diagnostics.

Modem
Modem

The POTS modem section is handled by a Si2457 System-Side device & Si3018 Line-Side device pair.