Diode has continuity in both directions?

[Vonwolf]

While I am waiting on parts I figured I might as well follow the Service Manual Starter Circuit Diagnostics and try to solve this starter button problem I’ve had since 2010, when I finally gave up on it and let her sit. I found I had a bad starter circuit and side stand relays. I also found that my Diode had continuity in both directions on both circuits, but the resistance was good on the 3^rd. I replaced the relays back in 2010, but I didn’t check the diode. I’m not real familiar with how this diode functions in the starter circuit, but I do know you should only have continuity in one direction, would this burn out my new relays, I’ve been hammering in the starter pretty hard trying to get that blue/white wire to do what it’s supposed to do so I might have cooked them I’m not sure. I’m replacing it all again along with the diode and praying the started button works

[bkuhr]

Both diodes are used in the safety logic to prevent starter operation in gear or side stand down. They prevent backfeed to the safety relays(sidestand and start cutout). Both are wired in series to relay coils, so if you test in circuit, it would be possible to read continuity in both directions. Best to remove the diodes from the circuit and test again.

[Vonwolf]

Both diodes are used in the safety logic to prevent starter operation in gear or side stand down. They prevent backfeed to the safety relays(sidestand and start cutout). Both are wired in series to relay coils, so if you test in circuit, it would be possible to read continuity in both directions. Best to remove the diodes from the circuit and test again.

 

I wasn't aware there were 2 diode's in the circuit, I'll have to find the other one and try again. This starter issue is like a quest o can't find any reason for it, the old 2 brush starter I think is the original culprit, it always turned the motor really slow. I'm pretty sure all that slow grinding cooked something, I just have to figure out what and my constant hammering on the solenoid has burned a few, that probably did my relays no good.

[M61A1MECH]

I have not seen the diagram of this circuit, but speaking in general terms.

 

If the diode is in series with the coil, it should still act the same as any diode, continuity in one direction and open in the other, the relay coil in that configuration will not change that.

BUT If the diode is in parallel with the coil , now you should get continuity in both directions, however, in one direction where it is going thru the coil only, you should have continuity with some resistance in the circuit that is indictive of the coil's resistance.

 

The diode in parallel with the coil is pretty common in aircraft wiring, this eliminates the spike caused as the coil voltage collapses when the relay is de-energized, thos spikes raise havoc with sensitive electronics used in aircraft comms and instument systems.

[Vonwolf]

The 3rd circuit had resistance within spec, but 1 and 2 had continuity pos/neg or neg/pos with the ignition on or off. The manual wasn't real clear on key on or off and did not identify the circuits and it says nothing about a second diode, but they seem to be known for leaving things out. They might think you should just know this stuff iff you're messing with it, they're wrong.

[Neil86]

The component you are testing should be unplugged from the harness so you are only testing continuity from point A to B.

Otherwise it could be taking an alternate path through the harness.

[Vonwolf]

The component you are testing should be unplugged from the harness so you are only testing continuity from point A to B.

Otherwise it could be taking an alternate path through the harness.

 

Thanks that's another thing that's not real clear in the manual. I'll have to pull it off and test again. I thought I was on to something, this might leave me scratching my head. I've got one 750 Yamaha buried in the back yard if I don't figure this out soon this Venture will be right next to it.

[Vonwolf]

I checked it unplugged and the D1&D2 circuits both had .600 ohmx2k, I don't have a 1k setting and the R circuit had 0 ohm. So the continuity does only go 1 way but it's not infinite it has some resistance and haveing no resistance at the R circuit where 8ohm is indicated. I have no idea how this impacts the starting circuit, but a new one's on its way so I just have to wait and see

[flyday58]

1st Gen Wiring Schematics 1983 - 1993

 

Try these.

[Vonwolf]

I want to thank all of you that took the time to try and get me through this mess and a big thank you to neil86 who took the time and called me, somehow getting it through my very thick skull that something didn't sound right with my solenoid, be it new or used. It turns out that somehow I had the Pos and Neg posts reversed, I have no idea how I did it and I feel like a complete fool, but I unbolted the battery cables spun the solenoid around 180 deg, hooked them back up, grounded the blue/white wire to the battery and I heard the sweetest sound I've heard in a long time. The solenoid "clicked", it was great! I still have problems with the relays and all but by now I could fix that stuff with my eyes closed, I mean I drove the bike for about a year with the solenoid in backward 's now that takes talent right? I'm sorry for burning up so much bandwidth and everyone's time with such a dumb mistake hopefully I'll think things through a little better.

[Neil86]

Glad to help and good to hear progress is being made!!

[flyday58]