One for the Boffins

[addo]

Never seen it before.

http://www.ebay.co.uk/itm/261200391005" onclick="window.open(this.href);return false;

Anyone have an opinion?

[CitroJim]

He's dead right the original has design deficiencies Adam... The main one being no emitter resistors to allow the pair of darlingtons to current-share to a greater degree than they can otherwise...

I'm concerned the active devices don't seem to be attached to any meaningful heatsink.

Also, looking at the PCB closely it's going to fail spectacularly as all four pins of the 4-way connector appear to be shorted together. Maybe just the way the picture is taken... I've got another after-market one sitting here. Beautifully made except it has a pair of NPN MJ11016 rather than the correct PNP MJ11015 and of course because of that it's nothing more than an ornament.. Until I replace the darlingtons that is...

The biggest clincher is that it's made in China and looks to be very poorly built - very amatuerish..

Personally I'd not go near it. 18 quid will buy several pairs of MJ11015s to keep the original going. It's not as if they pop every week is it?

Invest in a stock of MJ11015s - it makes far more sense.

[addo]

My original Xantia one has completely roasted the tracks, so I need a starting point in the form of a rebuildable board. The hardwired resistor setup in place of my glovebox is getting a bit stale for laughs.

A blackly funny mishap with panic braking and a slippery length of hardwood door jamb resulted in the slider panel getting an almighty whack; since then the aircon has run faultlessly. So a nice variable speed fan would really top it off.

[spider]

It does look poorly made, more like a home / hobby job from obtaining some pcb board, some etch chemicals (ferric chloride probably, nasty stuff!) and an etch resist pen.

[CitroJim]

My original Xantia one has completely roasted the tracks.

I'm sure someone on here can do you one Adam...

[RichardW]

I've got a board with broken transistors (probably! - it went full bore for a couple of weeks, then started working again ) on it if anyone wants it....

I bought a replacement from e-bay that was original design, under £20, fitted with the correct transistors, and works fine - as the original lasted nearly 140k miles, I think I'll take the chance on the design flaws