EdSanders

1980 928
L-Jetronic

I have determined the cause of a no start was a defective "ignition control unit' via replacement with good working unit. I am attempting a repair of the defective unit and have determined that the type T0-3 flat metal cased transistor is defective. The only identifying marks are an icon resembling a bolt with round heads within a circle and the numeric notation of [0011 0/3].
Would anyone have any info/source for replacement of this transistor ?

Thanks.
Ed

Lizard928

Ed,

I should have a good one of those boxes coming off a running car if you are interested in a working unit let me know.

I cannot help you with your question though.

EdSanders

Greetings Colin,
Thanks for your offer. However, I had a replacement on the shelf waiting. I am now trying to repair the defective unit to go back onto the shelf. I am hoping a Renner has an electrical schematic or knowledge about sourcing/cross referencing the specific transistor.
Cheers,
Ed

hacker-pschorr

All L-Jet owners should have one in the car as a spare, I've had two fail.

Currently I have four spare's.

John Speake

If they're that unreliable I better start offering a repair service :-)

hacker-pschorr

Every CIS 928 also has the same box.
Quite a few 911's (78ish - late 80's?) use a six cylinder version of the same box. A popular upgrade is a box by Permatune. I know more 911 owners who have tossed the aftermarket box into the garbage in favor of the OEM. It's supposed to be an added spark box like MSD for the Porsche. They used to make a 928 specific one too.

I often wonder how many CIS / L-Jet owners who are having intermittent issues are suffering from a malfunctioning ignition box.

The green wire plugs into this box with give the tach signal to the dash and L-Jet brain telling it when to fire, and the Coil. When these boxes start to act up they screw up the entire harmony of the engine. No different than a shorting out green wire.

I also found three corroded wire ends in the plug for this box. Just little things that go un-noticed by most techs that can cause all kinds of odd running issues.

danglerb

Just a wild thought, take a good unit and measure the characteristics of the transistor and find an equivalent part.

EdSanders

Hi Colin,
I have contacted several different sources including Bosch and it seems a no go without knowledge of the required transistor parameters. It seems such a shame to abandon a DIY for want of a small transistor. I may have an interest in taking you up on your offer of the L-Jetronic ignition unit as a backup replacement. Please advise. 1980 928
Cheers,
Ed [sandersedward@sbcglobal.net]

danglerb

If you trace out the circuit a decent EE might be able to figure out what sort of transistor would work.

John Speake

If that igntion box is similar to the Bosch 0 227 300 004 used on 911's then that device is an NPN switching transistor Emmittier is connected to ground in the circuit. It's function is the oscillator.

Shouldn't be too difficult to find a replacement. The reason you can't trace the part number is that Bosch often use their own P/N to stop what you are tring to do :-)

Walt L

Hey Colin,
A good box off a running car eh.............

Walt

EdSanders

Thanks John,
I just hate to discard the module for want of a single power transistor. Your info will be helpful in tracing down a replacement transistor.

Ed Sunny So . Californ

Bill 86.5 928s

As John Speake mentions, it somewhat looks like a 2N3055 switching/high current NPN transistor. What throws it off is the fact that the transistor in the picture is a three legged device. Now if one of those legs is part of the case of the transistor then a 3055 may work fine. This is a warning though and be careful that you do not lose the mica dielectric insulator under the transistor, also looking at the picture it appears that the transistor is isolated from the heatsink. It is very important that the case does not short to ground/case of the ECU or the heatsink. The case is the collector and usually the business/output portion of the transistor. That is of course if it is of the NPN or 3055 equivalent type...what I am trying to say is this transistor can be ruined very easily if you are not careful....Bill