Can anybody work out a replacement transistor? BMW E36 ECU

[ardy89]

Hi all,

Having spent a few hours last week tracing the cause of a misfire I have discovered a transistor has blown inside the ECU:

https://ibb.co/TqCnPR9

Now it seems rather difficult to get a hold of one of these, with exception of getting it from America. I could also buy another ECU and transfer into mine, something I am looking into.

Does anyone here understand the specification of transistors and can recommend the equivalent part from a different manufacturer. From my research, the transistor I am replacing is a Motorola STP8055.

Any help would be appreciated.

Cheer

Rob

 

[Atari]

Might be worth speaking to Enda from End Tuning here in Birmingham. He knows his way around ECU's and I've seen him do a number of repairs and fault finding the PCB's. He may be able to point you in the right direction.

Nice bloke too!

 

[Orionaut]

OTOH, you could always go down the remanufacture route.

There are a lot of companies in the game, some better than others, but I have always found this company satisfactory.

https://www.actronics.co.uk/

 

[jsmoke]

Well this comes up for a search of "r738" transistor so maybe it's the same transistor under a different name. Contact mouser.

https://www.mouser.co.uk/ProductDet...IvZ9jH6R4S8XWoDBdKvVoFQUBEbXNpIoaAjbjEALw_wcB

 

[ardy89]

Thanks for the advice guys I've gotten in touch with Mouser.

Can anyone see a reason why swapping the transistor wouldn't work? Unless of course more damage was caused than can visibly be seen?

Thanks

Rob

 

[bremen1874]

It'll depend on what caused it to fail in the first place. It could go bang again as soon as you power it back up.

 

[ardy89]

It'll depend on what caused it to fail in the first place. It could go bang again as soon as you power it back up.

Sorry I should have said this in the original post. The blown transistor was caused by a faulty ignition coil. This has since been replaced.

 

[jsmoke]

If it's only a couple quid for the new trans then I can't see any harm in trying although possible other components have been damaged. You'd really need to use an oscilloscope and look at the waveforms at different section to really know, but you wouldn't be able to get these waveforms anyway. Maybe a multimeter could be of some use otherwise it's a case of trial and error or replace whole ECU.

 

[paradigm]

The most likely scenario is that the transistor simply failed in a closed state and shorted something to ground. With the ECU not really getting external interference (physically, like liquid ingestion or taken a whack), it’s far more likely to just be failure rather than that being the symptom. Of course a nearby filtering cap or pull down resistor could have dragged the line short thus killing the transistor, but you can measure the resistance to ground on each of the transistor pin pads once you’ve removed the failed transistor from the board.

 

[Adam_151]

I cant seem to find a datasheet for the STP8055 however on a web search it seems to come up with the fact its a IGBT intended for ignition coil drivers (which fits!) and that the fairchild ISL9V3040P3 https://docs.rs-online.com/bbd9/0900766b813a1e81.pdf )might be a replacement, someone else says have used fairchild ISL9V5036P3 ( https://docs.rs-online.com/016c/0900766b816f79eb.pdf )These look like very similar parts, just with the later having a higher switching capacity, but lower breakdown voltage, I'm guessing either one would be an alright replacement

RS have both in stock (although minimum order of 5 of each, but at about 2 quid or something per part not end of world!)

 

[broadbandylegs]

Sorry to reopen a dormant thread - but did the above work for the original poster? I have the same problem and have been looking around for weeks for a solution - this is the closest to a solution that I've found
My ECU is Siemens MSS50.1 5WK9 026
Any advice greatly appreciated!