Help! Fried voltage regulator?

sunray · Post by **sunray** » Fri May 07, 2010 10:47 pm

I am not a surface mount type guy so I am only guessing. The three pin part in my old mjlj has a big heat crack across it and the unit is inop. Its a part marked WO6239 with an LESOABP below that. Can I get this part locally for a race tomorrow?

sunray · Post by **sunray** » Sat May 08, 2010 4:40 am

Okay so a friend of mine soldered in a new voltage regulator onto the board nut the mjlj will not work. I tried loading new firmware but it gets stuck with a neverending pulse break. Any ideas that could see me racing tomorrow or is it just dead for good?

NITROPIXIE · Post by **NITROPIXIE** » Tue May 11, 2010 5:52 pm

Sorry for late reply.

With the voltage regulator cracking i would of thought there would be a bit more damage to other components or board tracks to be honest.

There are a few other checks we can do to double check some circuitry and components. Do you have a multimeter or similar and have you had much experience with circuit boards, did you build your own mjlj??

Ryan

sunray · Post by **sunray** » Tue May 11, 2010 7:40 pm

I do have a good DMM and am very capable when it comes to electrical. I am an auto tech so I also have my trusty labscope too. I have not done any surface mount or though holes work so I did not assemble my mjlj. Its a version 3 unit so if I knew where to look for what values then that would be awesome.

Brent sent me a pm indicating that other components are likely faulty. I suspect that the eeprom is totally fubar, lol!

NITROPIXIE · Post by **NITROPIXIE** » Tue May 11, 2010 8:01 pm

Well the eeprom is slightly harder to come by, probably what brent has left but all the other components are pretty easy and you could just change them as they cost very little.

I would personally go along most of the common tracks first, such as ground, 5v, etc to make sure all components would be able to recieve power. Do this by eye firstly looking at the tracks detail, then with your dmm, set in Ohm (or bleep for continuity if you have that option).

Example (this will check the tracks that give U1 eeprom chip 5v)
From 12v molex to D2
then other side of D2 to U3 or D3
then the other side of U3 or D3 to pin 16 of U1

I will send you the schematic for the whole circuit if you don't aleady have it and if you need further help to follow it in more detail then get in touch.

Also from the ground pin of the molex to the ground pin of all the chips at least on the board. Don't worry too much if there is damage on the tracks of the board. If there is fine damage the run a little solder across the gap or if bigger then use some thin wire.

The mjlj circuit board is not designed for using high current as high current is not needed for this circuit. If there has been enough current to damage the voltage regulator then there maybe damage elsewhere, whether it be board or component.

Post by **brentp** » Wed May 12, 2010 2:50 am

What eeprom?

Are we talking V3 or V4? I think you're on a V3? As NITROPIXIE describes, if the voltage regulator failed it might've taken other components with it. Post a pic of the board if you can!

sunray · Post by **sunray** » Wed May 12, 2010 5:10 am

Well its a version 3 board and its over at my friend's house right now. He is going to tinker with it while I wait for the new version 4 kit I have ordered. You guys are still in WA right so it should take too long?

Oh by the way, thanks very much for the diagram Ryan.

BRUCEROE · Post by **BRUCEROE** » Wed May 12, 2010 1:52 pm

If a voltage excess blew up one integrated circuit, it likely damaged all the ICs. Even an IC that seems to have survived, may fail soon (happened to me). I'd replace them all.

Is there a V4 schematic diagram available? Bruce Roe

Autosport Labs

Help! Fried voltage regulator?

Help! Fried voltage regulator?

VOLTAGE EXCESS