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Sony PS3 APS-231 Power Supply Voltage Mod

PSU Ratings
PSU Ratings
PSU Ratings

I was recently given a Sony PS3 with a dead disc drive, and since I’m not a console gamer I figured I’d see if there were any handy parts inside. Turns out these units contain a rather nice SMPS, the Sony APS-231 with a high power 12v rail, rated at 23.5A. A bit of searching around discovered a thread on the BadCaps Forums about voltage modding these supplies for a 13.8v output, suitable for my Ham radio gear.
These supplies are controlled by a Sony CXA8038A, for which there is very little information. Active PFC is included, along with synchronous rectification which increases the efficiency of the supply, and in turn, reduces the waste heat output from the rectifiers.

Regulation Section
Regulation Section

Like many of the SMPS units I’ve seen, the output voltage is controlled by referencing it to an adjustable shunt reference, and adjusting the set point of this reference will in turn adjust the output voltage of the supply, this is done in circuit by a single resistor.

Here’s the regulator section of the PSU, with the resistors labelled. The one we’re after changing is the 800Ω one between pins 2 & 3 of the TS2431 shunt reference. It’s a very small 0402 size resistor, located right next to the filter electrolytic for the 5v standby supply circuit. A fine tip on the soldering iron is required to get this resistor removed.

Attachment Points
Attachment Points

Once this resistor is removed from the circuit, a 1KΩ 18-turn potentiometer is fitted in it’s place, from the Anode (Pin 3) to the Ref. (Pin 2) pins of the TS2431 shunt reference. I initally set the potentiometer to be the same 800Ω as the factory set resistor, to make sure the supply would start up at a sensible voltage before I did the adjustment.

Potentiometer
Potentiometer

The pot is secured to the top of the standby supply transformer with a drop of CA glue to stop everything moving around. The supply can now be adjusted to a higher setpoint voltage – 13.8v is about the maxumum, as the OVP cuts the supply out at between 13.9v-14v.

Modded Voltage
Modded Voltage

After doing some testing at roughly 50% of the supply’s rated load, everything seems to be stable, and nothing is heating up more than I’d expect.

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Anker PowerPort Speed 5 USB Rapid Charger Teardown

Front
Front

Here’s a piece of tech that is growing all the more important in recent times, with devices with huge battery capacities, a quick charger. This unit supports Qualcomm’s Quick Charge 3 standard, where the device being charged can negotiate with the charger for a higher-power link, by increasing the bus voltage past the usual 5v.

Rear
Rear

The casing feels rather nice on this unit, sturdy & well designed. All the legends on the case are laser marked, apart from the front side logo which is part of the injection moulding.

Specifications
Specifications

The power capacity of this charger is pretty impressive, with outputs for QC3 from 3.6-6.5v at 3A, up to 12v 1.5A. Standard USB charging is limited at 4.8A for the other 3 ports.

Ports
Ports

The two of the 5 USB ports are colour coded blue on the QC3 ports. The other 3 are standard 5v ports, the only thing that doesn’t make sense in the ratings is the overall current rating of the 5v supply (4.8A), and the rated current of each of the ports (2.4A) – this is 7.2A total rather than 4.8A.

Top Removed
Top Removed

The casing is glued together at the seam, but it gave in to some percussive attack with a screwdriver handle. The inside of this supply is mostly hidden by the large heatspreader on the top.

Main PCB Bottom
Main PCB Bottom

This is a nicely designed board, the creepage distances are at least 8mm between the primary & secondary sides, the bottom also has a conformal coating, with extra silicone around the primary-side switching transistor pins, presumably to decrease the chances of the board flashing over between the close pins.
On the lower 3 USB ports can be seen the 3 SOT-23 USB charge control ICs. These are probably similar to the Texas Instruments TPS2514 controllers, which I’ve experimented with before, however I can’t read the numbers due to the conformal coating. The other semiconductors on this side of the board are part of the voltage feedback circuits for the SMPS. The 5v supply optocoupler is in the centre bottom of the board.

Heatsink Removed
Heatsink Removed

Desoldering the pair of primary side transistors allowed me to easily remove the heatspreader from the supply. There’s thermal pads & grease over everything to get rid of the heat. Here can be seen there are two transformers, forming completely separate supplies for the standard USB side of things & the QC3 side. Measuring the voltages on the main filter capacitors showed me the difference – the QC3 supply is held at 14.2v, and is managed through other circuits further on in the power chain. There’s plenty of mains filtering on the input, as well as common-mode chokes on the DC outputs before they reach the USB ports.

Quick Charge 3 DC-DC Converters
Quick Charge 3 DC-DC Converters

Here’s where the QC3 magic happens, a small DC-DC buck converter for each of the two ports. The data lines are also connected to these modules, so all the control logic is located on these too. The TO-220 device to the left is the main rectifier.

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Mercury 30A Ham Radio SMPS

Mercury 30A SMPS
Mercury 30A SMPS

After having a couple of the cheap Chinese PSUs fail on me in a rather spectacular fashion, I decided to splash on a more expensive name-brand PSU, since constantly replacing PSUs at £15 a piece is going to get old pretty fast. This is the 30A model from Mercury, which seems to be pretty well built. It’s also significantly more expensive at £80. Power output is via the beefy binding posts on the front panel. There isn’t any metering on board, this is something I’ll probably change once I’ve ascertained it’s reliability. This is also a fixed voltage supply, at 13.8v.

Rear Panel
Rear Panel

Not much on the rear panel, just the fuse & cooling fan. This isn’t temperature controlled, but it’s not loud. No IEC power socket here, the mains cable is hard wired.

Main Board
Main Board

Removing some spanner-type security screws reveals the power supply board itself. Everything on here is enormous to handle the 30A output current at 13.8v. The main primary side switching transistors are on the large silver heatsink in the centre of the board, feeding the huge ferrite transformer on the right.

Transformer
Transformer

The transformer’s low voltage output tap comes straight out instead of being on pins, due to the size of the winding cores. Four massive diodes are mounted on the black heatsinks for output rectification.

 

SMPS Controller
SMPS Controller

The supply is controlled via the jelly bean TL494 PWM controller IC. The multi-turn potentiometer doesn’t adjust the output voltage, more likely it adjusts the current limit.

Standby Supply
Standby Supply

Power to initially start the supply is provided by a small SMPS circuit, with a VIPer22A Low Power Primary Switcher & small transformer on the lower right. The transformer upper left is the base drive transformer for the main high power supply.