This is a small 120W power inverter, intended for small loads such as lights, fans, small TVs & laptop computers.
End Cover
End cover of the unit, 12v DC input cord at the top, power switch & indicator LEDs at the bottom.
Mains Output
Opposite end of the unit, with the standard 240v AC 50Hz Mains output socket.
Cover Removed
Cover removed from the top of the unit. Main power transformer is visible in the centre here, MOSFET bank is under the steel clamp on the left, the aluminium case forms the heatsink.
PWM Controllers
On the right is a KA3525 switchmode PWM controller & on the left is a LM324N quad Op-Amp IC. The buzzer on the far left is for the low battery warning.
PCB Removed
PCB removed from the casing, with the MOSFET bank on the right hand side. Two potentiometers in the centre of the board tweak the frequency of the switcher & the output voltage.
Here is an old electrochemical type carbon monoxide detector cell, from Monox. Hole in the centre is the inlet for the gas under test. DO NOT TRY THIS AT HOME! Electrochemical cells contain a substantial amount of sulphuric acid, strong enough to cause burns.
This is a type of fuel cell that instead of being designed to produce power, is designed to produce a current that is precisely related to the amount of the target gas (in this case carbon monoxide) in the atmosphere. Measurement of the current gives a measure of the concentration of carbon monoxide in the atmosphere. Essentially the electrochemical cell consists of a container, 2 electrodes, connection wires and an electrolyte – typically sulfuric acid. Carbon monoxide is oxidized at one electrode to carbon dioxide while oxygen is consumed at the other electrode. For carbon monoxide detection, the electrochemical cell has advantages over other technologies in that it has a highly accurate and linear output to carbon monoxide concentration, requires minimal power as it is operated at room temperature, and has a long lifetime (typically commercial available cells now have lifetimes of 5 years or greater). Until recently, the cost of these cells and concerns about their long term reliability had limited uptake of this technology in the marketplace, although these concerns are now largely overcome. This technology is now the dominant technology in USA and Europe.
Rear
Rear of unit with connection pins. Hole here is to let oxygen into the cell which permits the redox reaction to take place in the cell when CO is detected, producing a voltage on the output pins.
Disassembled
Cell disassembled. The semi-permeable membrane on the back cover can be seen here, to allow gas into the cell, but not the liquid electrolyte out. Cell with the electrodes is on the right, immersed in sulphuric acid.
Platinum Electrode
Closeup of the electrode structure. Polymer base with a precious metal coating.
This is a device to use an IDE or SATA interface drive via a USB connection. Here is the front of the device, IDE interface at the bottom, 2.5″ form factor.
PCB Top
PCB removed from the casing. USB cable exits the top, 12v DC power jack to the left.
SATA interface below the DC Jack.
Molex connector below SATA is the power output for the drive in use. This unit has a built in 5v regulator.
PCB Bottom
Bottom of the PCB showing the interface IC.
Drive Adaptor
Adaptor to plug into the 44-pin 2.5″ form factor IDE interface on the adaptor, converts to standard 40-pin 3.5″ IDE.
Power Cable
Power pigtail with standard Molex & SATA power plugs.
Here is one of the first USB tuners that was available from Hauppauge Computer Works. Totally analog tuner of course, this model required 2 cables – a USB interface & a sound cable for the audio output of the tuner.
I/O
A/V connections.
Label
For those who are interested. Here is the label with the model details.
Antenna Connection
Connection to an external antenna.
PCB Bottom
Bottom of the PCB.
PCB Top
Top of the PCB showing the USB interface IC (top left), cache memory (top right) & the main tuner assembly.
A quick post documenting a DPSS laser module i salvaged from a disco scanner. Estimated output ~80mW
Diode Connection
Connection to the 808nm pump diode on the back of the module. There is a protection diode soldered across the diode pins. (Not visible). Note heatsinking of the module.
Driver PCB
Driver PCB. This module was originally 240v AC powered, with a transformer mounted on the PCB with a built in rectifier & filter capacitor. I converted it to 5v operation. Emission LED on PCB.
To help make my system more efficient, a pair of switching regulators has been fitted, the one shown above is a Texas Instruments PTN78060 switchmode regulator module, which provides a 7.5v rail from the main 12v battery pack.
A Lot like the LM317 & similar linear regulators, these modules require a single program resistor to set the output voltage, but are much more efficient, around the 94% mark at the settings used here.
The 7.5v rail supplies the LM317 constant current circuit in the laser diode driver subsection. This increases efficiency by taking some voltage drop away from the LM317.
5v Regulator
The 7.5v rail also provides power to this Texas Instruments PTH08000 switchmode regulator module, providing the 5v rail for the USB port power.
The parts arrived for my adjustable laser diode driver! Components here are an LM317K with heatsink, 100Ω 10-turn precision potentiometer, 15-turn counting dial & a 7-pin matching plug & socket.
Driver Schematic
Here is the schematic for the driver circuit. I have used a 7-pin socket for provisions for active cooling of bigger laser diodes. R1 sets the maximum current to the laser diode, while R2 is the power adjustment. This is all fed from the main 12v Ni-Cd pack built into the PSU. The LM317 is set up as a constant current source in this circuit.
Installed
Here the power adjust dial & the laser head connector have been installed in the front panel. Power is switched to the driver with the toggle switch to the right of the connector.
Regulator
The LM317 installed on the rear panel of the PSU with it’s heatsink.
Connection
Connections to the regulator, the output is fully isolated from the heatsink & rear panel.
Here is a cheapo 500W rated ATX PSU that has totally borked itself, probably due to the unit NOT actually being capable of 500W. All 3 of the switching transistors were shorted, causing the ensuing carnage:
AC Input
Here is the AC input to the PCB. Note the vapourised element inside the input fuse on the left. There is no PFC/filtering built into this supply, being as cheap as it is links have been installed in place of the RFI chokes.
Input Side
Main filter capacitors & bridge rectifier diodes. PCB shows signs of excessive heating.
Filter Caps Removed
Filter capacitors have been removed from the PCB here, showing some cooked components. Resistor & diode next to the heatsink are the in the biasing network for the main switching transistors.
Heatsinks Removed
Heatsink has been removed, note the remaining pin from one of the switching transistors still attached to the PCB & not the transistor 🙂
Transformers
Output side of the PSU, with heatsink removed. Main transformer on the right, transformers centre & left are the 5vSB transformer & feedback transformer.
Output Side
Output side of the unit, filter capacitors, choke & rectifier diodes are visible here attached to their heatsink.
Comparator
Comparator IC that deals with regulation of the outputs & overvoltage protection.
Here we have a Dremel MultiPro rotary tool, a main powered 125W 33,000RPM bit of kit.
Motor Assembly
Here the field & controller assembly is removed from the casing.
Armature
Here is the armature, which rotates at up to 33,000RPM. The brushes rise against the commutator on the left, next to the bearing, the cooling fan is on the right hand side on the power output shaft, the chuck attaches at the far right end of the shaft.
Speed Controller & Brush Box
Here is the speed controller unit, inside is an SCR phase angle speed controller, to vary the speed of the motor from 10,000RPM to the full rated speed of 33,000RPM.
Mains Filter
This is the mains filter on the input to the unit, stops stray RF from the motor being radiated down the mains cable.
An ICL barcode scanner from the 80s is shown here. This is the top of the unit with cover on.
Cover Removed
Plastic cover removed from the unit showing internal components. Main PSU on left, scan assembly in center. Laser PSU & Cooling fan on right. Laser tube at top.
Scan Motor
Closeup of laser scan motor. This unit scans the laser beam rapidly across the glass plate to read the barcode.
Controller PCB
View of the bottom of the unit, showing the controller PCB in the centre.
Scan Motor Driver
The 3-phase motor driver circuit for the scan motor. 15v DC powered.
Laser Unit
This is the laser unit disconnected from the back of the scanner. HT PSU is on right hand side, beam emerges from optics on left.
Laser Unit Label
This unit is date stamped 1987. The oldest laser unit i own.
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