I have an old 2A0 Tech edge wide band controller that i put together probably 15 years ago. Its been a reliable unit but after a long period of storage it seems to have failed.

When in use it will only output 5v no matter what the engine is doing. If i blow lots of butane over the sensor i can get the voltage to drop but nothing like it should.

I've bought a new (but from eBay admittedly) Bosch 6066 sensor and get exactly the same result.

So far i have checked the sensor cable several times, re-soldered all the cable connections, shortened the cable and re-made the connections. Pretty sure its not the cable!

There's nothing obviously fried on the circuit board and I've been over just about all of the joints and re-soldered them.

I've also tried moving the Op-amps around to see if that changed the symptoms, no difference.

I've re-flashed to the latest firmware and re calibrated. During re calibration i noticed that the sensor seems to react properly to air changes, if i were to blow on the sensor the readings jumped a lot as you would expect.

Unfortunately the support forum seems to be dead these days, its not even possible to register. Thought i'd ask on here on the off chance before i condemn the lot to the bin!

Any ideas?

I will be starting another thread for opinions on a replacement unit.

Cheers
Dan