Making an Aliexpress arcade chassis a bit better

[Big_P Big_p]

These guys are actually not too bad if you change out a few things to fix some of the reliability problems. Picture is clear on a good tube but there is no degaussing circuit or place to plug it.

I documented the steps to rebuilding one of these here: Post in thread 'Chandy Cab Restoration' https://www.arcade-projects.com/threads/chandy-cab-restoration.33621/post-463044

And just wanted to create a thread for anyone looking at these in the Monitors section of the forum. I don't think I documented (or remember) what the rectifier diodes were replaced with exactly but they went up to 3A and they were something pretty standard from a reliable manufacturer.

I have been considering designing a basic degaussing circuit for the Chandy and if I do I'll document it here.

 

[Big_P Big_p]

OK... I have am idea for a degaussing circuit.

AC live to an NO relay, AC neutral to one pin on the degaussing coil.
The other NO relay goes to a PTC thermistor. The other side of the PCT goes to the other side of the degaussing coil.
The AC goes to a AC to 12v DC converter.
12v DC from the converter goes to a 555 timer, with pin 2 of the timer connecting to momentary switch. Pin 5 is tied to gnd with an 0.01uf cap.pins 6 & 7 are tied together, pin 7 is tied to VCC with a 270ohm resistor, 10uf cap between pin 6 and GND.
Output of the 555 (pin 3) goes to a 1k ohm resistor which then goes to the base of a 2n2222 transistor. Emitter of the transistor to gnd. Collector to 1 side of the relay coii other end of the relay coil to 12v DC with a 1n4007 diode across the relay coil (cathode to the 12vdc side).
Pressing the switch activates the 555, the 555s output in turn activates the transistor which energises the relay allowing 120VAC or 250VAC to flow through the degaussing coil via the PTC. As current flows the initial high PTC current is reduced gradually. After 3 secs the 555 shuts off deactivating the relay.

Is the theory sound. Does that work? I have never built or had to build one of these before.

 

[Big_P Big_p]

Something like this maybe. Alot of assumptions and "sounds about right" in this at the minute.