The 2DM860H chinese controllers vs the rest?

[Kitwn]

Doddy,
That's a brilliant job, thank you!

I know most people want to just plug-and-play with modules but when you see how simple it is to fix some of the faults for yourself and realise how cheap some of the components are it saddens me to see people just give up and trash expensive modules that can be repaired for very little. Most faults with this kind of device will be in the power supply or output devices, all of which tend to be the large components that cost very little and are easy to replace as you've demonstrated. RS components will send you a bag of 5 new transistors for less than the cost of a pint, including postage!

[Doddy]

A little unfair there - there's a long way to go before this works again, and I'm carrying cost and risk in repairing it - for some the downtime wouldn't warrant the cost of replacing with new. Also, to be absolutely honest, I don't think it's cost-effective for me to have spent trying to clear some form of metal debris from the fan supply solder pads for the last hour (finally resolved with a 0.4mm drill - which I managed to snap in the hole) - it was clear on inspection that the fan wiring was a bodge job with the assembler unable to poke the wire through the hole - silicone hides a whole multitude of sins on PCB assembly in china.

If it wasn't for this damned lock-down I'd throw the controller in the bin and be done with it, but being forced to spend time either with the wife or with a soldering iron, there's some curiosity value for trying to repair. But I do have some rather expensive tools to support that curiosity. Also for many in this game there's a lifetime of experience of feed rates and chip loadings that I just don't claim to understand, but then I wouldn't expect them to understand the behaviour of a h-bridge and failure modes of a MOSFET.

Horses for courses.

(but I'm determined now to get this sucker working again)