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Reverse engineering the Bosch K-Jet ignition module

Started by ptashek, 10 January 2013, 11:56 AM

lethy

Hey guys, I'm trying to fix my ign module, can you guys help me?
The R4 capacitor looks bad and the transistor made by bosch code 00119/187 failed the test with the multimeter (This test failed at step 3 and step 5), I couldn't find any capacitor with this capacitance nor the same type, is there any suggestions on what I could use as a replacement? And I have no idea what is the spec of this transistor, I saw you trying to figure it out what was a good replacement, but I would like to use another TO3, because others components seems to be good.

ptashek

Assuming your module is the same as the one I've used for this experiment:

* if you meant C4 capacitor, that one is 8.2uF/20V electrolytic.
* if you meant R4 resistor, that one is 3.3k.

For the transistor, you will need to to find a package equivalent of BUB323Z or BDW42G. The exact spec of the original is unknown. These two above worked as replacements in a prototype.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE (history, resto)

lethy

Quote from: ptashek on 08 April 2022, 11:30 AMAssuming your module is the same as the one I've used for this experiment:

* if you meant C4 capacitor, that one is 8.2uF/20V electrolytic.
* if you meant R4 resistor, that one is 3.3k.

For the transistor, you will need to to find a package equivalent of BUB323Z or BDW42G. The exact spec of the original is unknown. These two above worked as replacements in a prototype.

Mistyped, *C4, right. The only 8,2uF I found was 400v, I don't think that it's a problem, as long as it's more voltage, and not less than 20v. Right?

Do you know if there's any chance I can use BU931? This one was used on Bosch ign modules made here in Brasil, but on 4 cyl cars.

ptashek

Correct on the capacitor.
For the transistor, you would need to compare it's datasheet with the other two.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE (history, resto)