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914World.com _ 914World Garage _ MS with blown diodes

Posted by: bd1308 Mar 18 2006, 10:24 AM

does this actually happen during normal use?

I got a freebie MS last night but it needed some diodes and some transistors replaced.

if i were to get this working on the '14, would they blow out during normal use?

Thanks steven again for all of your help/patience and for helping me create the very first AWD 914

b

Posted by: Carrera916 Mar 18 2006, 10:34 AM

Come again?...you say AWD 914?

that would be really cool....what would you use as AWD driveline? Audi Quattro stuff? Ummm, i got these laying around here....maybe I ought to do that....I gotta be that !

As for the MS, nah, it sounded like the input voltage to the MS might have spiked too high for the watt rating of the diodes and resisters....take a picture of the PC board if you can...I'd like to see it....

Posted by: Dr Evil Mar 18 2006, 10:36 AM

No, not normal at all. Either the polarities of said componenets were not correctly observed, or parts with incorrect tolerances were used. The only other possibility I can think of is that it was installed in a hot area. Check the schematic to make sure.

Oh ya, and a possible spike.

Posted by: bd1308 Mar 18 2006, 10:58 AM

v1.01 without flyback module (which is presumably required for these 914 injectors)

pics later.

b

Posted by: Dr Evil Mar 18 2006, 11:01 AM

You may be the one in need of my v2 kit. I was going MS, but then got a 2.7 w/ CIS and decided to go MJLJ instead. I have the board with the chip programmer and the stimulator. the board is not completely assembled as I used many of the parts for the MJLJ project. PM me and we may be able to work something out. Also, I am likely to have some of the diodes left that you can have.

Posted by: bd1308 Mar 18 2006, 11:05 AM

i'm gonna go ahead and replace all of the diodes and transitors...

and then im gonna get the stimulator to see if i can get anything to work. I bet something spiked and it roached the diodes, but when im looking at this board, i dont see *ANY* melted or roached areas (roasted board) or anything that would indicate a problem. Besides the diodes that were 'unplugged' to ID the dead ones, I would think that this still works.

b

Posted by: kwales Mar 18 2006, 11:09 AM

Use little hair clips on the leads to act as heat sinks. Some people make good and sure the solder is heated, and sometimes damage the components. Use silicone heat grease if components attach to a heat sink.

Ken

Posted by: davep Mar 18 2006, 11:20 AM

Not sure about the flyback module function, however in electronics design one always puts a diode across the solenoid of a relay to suppress the spike that occurs when the solenoid is de-energized. The un-suppressed spike can damage other components in the circuit.

Posted by: rick 918-S Mar 18 2006, 11:44 AM

I have no idea what you guys are talking about, but it's cool! I have got to get with this lingo.

Posted by: tdsmoonchild Mar 18 2006, 01:24 PM

QUOTE (rick 918-S @ Mar 18 2006, 11:44 AM)
I have no idea what you guys are talking about, but it's cool! I have got to get with this lingo.

Posted by: Mueller Mar 18 2006, 01:47 PM

Blown diodes = operator error

on my 1st MS, I didn't follow the directions and didn't have the injectors hooked up with a relay...with the MS off, power was still going thru the injectors and made it way back to the MS, frying some parts....

not a bad idea to replace some of the components, the diode and transistors are dirt cheap.....

if you order from Mouser, there is no minimum purchase...for DigiKey, you must purchase at least $25 or get hit with a $5 fee.