Here is the lamp end of the physics package, with the voltageregulator & RFdriver for the lamp. The FETs soldered to the back of the housing are being used as heaters to maintain a constant temperature on the lamp in operation.
The temperaturesensor can be seen between the two FETs, with a single copper wire running around the housing to connect to it.
Main frequency synth board. This contains the RS-232 interface & the AD9830A from Analog Devices. This IC is a direct digital synthesizer & waveform generator.
This is a late 90’s business timeclock, used for maintaining records of staff working times, by printing the time when used on a sheet of card.
Here is the top cover removed, which is normally locked in place to stop tampering. The unit is programmed with the 3 buttons & the row of DIP switches along the top edge.
Closeup of the settings panel, with all the various DIP switch options.
Cover plate removed from the top, showing the LCD & CPU board, the backup battery normally fits behind this. The CPU is a 4-bit microcontroller from NEC, with built in LCD driver.
Power Supply & prinhead drivers. This board is fitted with several NPN Darlington transistor arrays for driving the dox matrix printhead.
Printhead assembly itself. The print ribbon fits over the top of the head & over the pins at the bottom. The drive hammers & solenoids are housed in the circular top of the unit.
Bottom of the print head showing the row of impact pins used to create the printout.
Bottom of the solenoid assembly with the ribbon cable for power. There are 9 solenoids, to operate the 9 pins in the head.
Top layer of the printhead assembly, showing the leaf spring used to hold the hammers in the correct positions.
Hammer assembly. The fingers on the ends of the arms push on the pins to strike through the ribbon onto the card.
The ring of solenoids at the centre of the assembly. These are driven with 3A darlington power arrays on the PSU board.
There is only a single drive motor in the entire unit, that both clamps the card for printing & moves the printhead laterally across the card. Through a rack & pinion this also advances the ribbon with each print.
Here is an old chemical dosing system for industrial washing machines. These units are 4-pump models, with dual pumpheads. The motors are reversed to operate alternate pumps in the same head.
From 2006, this is a fairly old unit, and made in the UK.
Main controller PCB, with interface to the power electronics via the ribbon cable, an external serial port for programming to it’s left. Powered by an ST microcontroller. The LCD is below this board.
Main power supply, sense input & motor driver boards. The PSU outputs +5v, +12v & +24v. The inputs on the lower left connect to the washing machine & trigger the pumps via the programming on the CPU. The motors are driven by L6202 H-Bridge drivers from ST.
Motor & gearbox assembly on the back of the pumphead. These are 24v DC units with 80RPM gearboxes.