Failed transistor in DME & ? can't cross reference, suggestions?

[mgoods50]

Here's a little history on the dead cylinder:
http://forums.bimmerforums.com/forum/showthread.php?t=1800513

I got around to pulling the DME, opening it up- and found what I believe is a trashed transistor, and a failing ground- possibly some other connections that are going as well. FOR SURE that transistor is shot- take a look!

I don't have much experience with circuit boards- so if there is something obvious, please point it out.

I have searched until I can't see straight anymore. I can't find a reference anywhere on this component, and would appreciate direction.

I've attached some pics.

DME # 484

[Mayorchuck]

Do you have a 404 or 484 DME?

[mgoods50]

Ugh- is it obvious I'm tired? (also battling bronchitis too) Sorry- it's a # 484 DME. I've edited my original post...

[Timm]

That's not a transistor - and will not be the cause of a single-cylinder misfire. It's certainly got hot (or has been replaced) but it doesn't look dead. Here's the transistor that fails when a single cylinder loses its spark:

http://www.meeknet.co.uk/E32/ECU/Index.htm

[mgoods50]

For the record- I do not believe it has been touched / replaced. The DME housing showed no signs of previous opening.

I have searched every combination of Bosch / Siemens / 30 191 / 9434 / 445 ET / VB 429 / 230 12 I can possibly think of.

I am no electronics component expert- but I've searched through a lot of material for more than 12 hours and I'm more confused than when I started.

Diode? Transistor? Regulator?

Whether it's the MAIN problem or not- I'm SURE it's contributing to the problem of issues in cylinder 8- fuel / spark / whatever.

I'm at a loss- hoping someone with more component experience can help--

[DUDMD]

Replace with another DME. Any 484 will work, just swap your EPROM chip into the new dme.

[mgoods50]

Replace with another DME. Any 484 will work, just swap your EPROM chip into the new dme.

I would rather use that as a last resort, since condition will be unknown until I open it up. At least if I replace this component, and re-flow some solder across those suspect joints, I'll feel a little better.

Some proactive searching revealed an orange-ish label DME, also #484, but non-EWS. Mine is EWS-II, so I'll have to replace with same- right? (retaining features of EWS ring / key transmitter etc.)

[Timm]

The component is a regulator - and has possibly got hot due to the additional current demanded by a faulty drive transistor for cylinder 8. You will not find the components listed anywhere, they were specifically manufactured for the ECU and not available from the manufacturer to the public. Unless you know the equivalent part, as was researched for the transistors, you will be out of luck. However, the regulator is working, you will get no sparks at all without it.

[DUDMD]

I would rather use that as a last resort, since condition will be unknown until I open it up. At least if I replace this component, and re-flow some solder across those suspect joints, I'll feel a little better.

Some proactive searching revealed an orange-ish label DME, also #484, but non-EWS. Mine is EWS-II, so I'll have to replace with same- right? (retaining features of EWS ring / key transmitter etc.)
484 DME's are easy to find and are cheap that you should just get a replacemnt and stop trying to fix your old one. All 484 DME's were EWS2 equipped, you can convert to a 404 DME. It's the same thing, minus the EWS2. Your transponder/EWS system will still work as a starter immobilizer, but will no longer prevent the engine from starting with a 404DME if someone were to hot wire the starter. I would call a 404 converted car an EWS1.5 car, it's more secure than EWS1, but less secure than EWS2.
Chances of someone stealing your E38 even if you completely remove the EWS system are very little, that it's not a major loss of security. Its' not a honda, people don't steal these.

[Hegemon]

Here's a little history on the dead cylinder:
http://forums.bimmerforums.com/forum/showthread.php?t=1800513

I got around to pulling the DME, opening it up- and found what I believe is a trashed transistor, and a failing ground- possibly some other connections that are going as well. FOR SURE that transistor is shot- take a look!

I don't have much experience with circuit boards- so if there is something obvious, please point it out.

I have searched until I can't see straight anymore. I can't find a reference anywhere on this component, and would appreciate direction.

I've attached some pics.

DME # 484
Definite you have some issues with the solder joints. There is also flux residue on the board from the original manufacture. That in itself is corrosive and over time will ruin the solder joints. If you are handy with a soldering iron I would touch up those solder joints and then locally clean the area as best as you can. If the joints are not totally corroded you can freshen them up and then ignore them for another 10-15 years.... many older vehicles have this problem, as do older electronics of any kind. The very thing thats makes soldering possible in a manufacturing environment is also one thing that will eat the joints over time. Flux, and Flux Residue. Cleanliness is next to Godliness in circuit board manufacturing.
'hege

[mgoods50]

Does anyone have a spare #484 DME they can part with reasonably? I'll also post a WTB thread.

I am going to call it quits on the component search. I cannot find any information anywhere. I'm still interested in any information-- for my own learning.

Thanks in advance-- and I'll update as things evolve!

[Mayorchuck]

I have one along with the EWS and key from my parts car. Think I will keep it as a package. They are on Ebay for about $60.