Diodes

[dnsey]

when looking at the other side of the board where it has sort of delaminated it a bit.

You might find that the board has become somewhat conductive, which can cause all sorts of problems.
If in doubt, cut out the damaged section of board and hard-wire the IC.
BTW, no offence, but there seem to be rather a lot of solder splashes around the replaced chip - I'd be inclined to clean up a bit before they cause trouble.

[CitroJim]

That's interesting Dave, one looks like it's been running a lot hotter than the other and yet both should be about the same as each are driving one electrovalve and both switch at the same time.

Looking hot is not necessarily a sign of failure though.

I fancy I've seen much the same in a Xantia ECU but can't remember exactly the circumstances.

Conceivably, if one electrovalve has been running with a duff diode for a very long time that may account for it...

[davetherave]

Interesting how it is the same chip on both boards though.

Thanks for the heads up on the solder, Ill give it a clean before it goes back on!
Dave

[xmexclusive]

Hi Jim & Dave

Have to dissagree on the heat affected VN05N's.
If they show physical signs of overheating they will not work correctly or adequately.
The spec sheet for the device states that built in thermal shut down circuitry is present.
This shut down operating plays havoc with the output waveform.

John

[CitroJim]

I'm just basing my observations on what I've seen in other electronic equipment John, very happy that you have more experience of Hydractive ECUs than I do...

[davetherave]

Ok Ill be replacing it just in case! Iv got a spare still!