Thanks Dell, it was a failed diode

[Kurt Barnhart]

Dell, it was indeed a failed diode causing my ignition switch not to shut the tractor down on my 12V 2N- replaced and problem solved. A couple of last questions to satisfy my curiosity. I put in a 1a 50V resistor which is a lot smaller than the one that was there so is the little one stout enough for the long haul or should I consider one that will handle more amps?

Also, since this last one failed while the tractor was in use was that just by chance or is that when they tend to fail because as I walked away from the tractor I thought "what if it fails between now and the next time I use it and then my ignition system gets fried"?

 

[Bob]

I do a LOT of alternator repair work and 12 Volt conversions and use 1N5408 diodes, 3A @ 1000 PIV and have never had one fail.

I pay about $.05 for them in quantity.

I'll mail anyone who wants one a 1N5408 for a SASE and an extra stamp.

So WHY use a wimpy diode? In THEORY a 50 or 100 PIV diode should work, but the diodes are subjected to voltage spikes from the ignition circuit and the alternator and wimpy diodes DO fail in this use.

So, use a wimpy diode and sooner or later it will come back to bite you in the butt!

 

[Dell (WA)]

Kurt......summtimes us guessers gitt lucky, but you were the one that figgered it out and did a replacement. Take Bob up on his offer of a "better" diode. .......Dell, the lucky

 

[GA Dave]

I convereted (Bubbafied) my 1958 IH 240 Utility to 12 volts several years ago and used three of these 1 amp rectifiers in parallel just because there were about twenty in the pack. If I remember correctly the Jim-Pak was less than two dollars. I'd Bubbafie my 49 8N to 12 volts but I'm afraid Dell would stripe my legs if I did. The only reason for the 240 12 volt conversion was because the 6 volt generator died and I had a GM alternator in the shop. David.......................

 

[Kurt Barnhart]

Bob, Thanks, send me your address and I'll get you an envelope and extra stamp.

Kurt

 

[Bob]

email [email protected]

 

[Dell (WA)]

Dave......while you may think you have 3-amps worth of diode protection in parallel, you really only have 1-diode worth of protection. You need a series resistor for each diode to "balance" the current draw. Its a semi-conductor thing. Unfortunately, I haven't had my cuppa kauphy yet and can't tell you what value of resistor. Its been 30-yrs since I did electronics design work and my brain been flooded with tractor problems overwhelming me brain (grin) ......Dell

 

[Bob Harvey]

AND the 'Ratboy' thing !! HPH >Dell

 

[ZANE]

There is a diode in every delco alternator. You can remove it from a parts alternator and use it for the diode to the field terminal of you alternator. It won't fail. I has one conductor on one side of the diode and three on the other side. Just cut off two of them and use the one left on the side that had three. Can't remember off hand which side goes to the hot side but just try it both ways. I don't even run an extra wire. Just put one end under the hot post of the alternator and the other to the fiels terminal by way of a jumper wire soldered to the diode with a spade connector on the other end.

Zane

 

[Dunk]

(quoted from post at 21:44:56 09/23/09) There is a diode in every delco alternator. You can remove it from a parts alternator and use it for the diode to the field terminal of you alternator. It won't fail. I has one conductor on one side of the diode and three on the other side. Just cut off two of them and use the one left on the side that had three. Can't remember off hand which side goes to the hot side but just try it both ways. I don't even run an extra wire. Just put one end under the hot post of the alternator and the other to the fiels terminal by way of a jumper wire soldered to the diode with a spade connector on the other end.

Zane

We need pics and diagrams.

 

[Anonymous-0]

Dell,1 diode will switch on first and carry the entire load.I use 1000 piv diodes on everthing.no sense in having a failure because of penny pinching.