Dyna S fried overnight - possible causes?

[Suzuki_Don]

I think you may have answered your own question. You left the ign ON overnight. Those modules are designed to switch ON, OFF, ON, OFF, etc as the magnet passes each module. If the magnet was positioned so that one module was ON all the time that could have caused it to fail. Have you ever felt how hot a condensor gets in points type ign if the ign is left on for some time. Same senario.

[Pendulum]

I think you may have answered your own question. You left the ign ON overnight. Those modules are designed to switch ON, OFF, ON, OFF, etc as the magnet passes each module. If the magnet was positioned so that one module was ON all the time that could have caused it to fail. Have you ever felt how hot a condensor gets in points type ign if the ign is left on for some time. Same senario.

I should have clarified. The battery was drained about 5 days before the Dyna died. I charged it up, and it held a charge until I rode the bike around the block. Parked the bike, and the next morning the Dyna S was dead. Battery was still at 12.7v.

[Suzuki_Don]

I still think the ign being left on overnight had weakened the module in some way and it failed at a later stage.

Did both modules fail or only one?

[Pendulum]

I still think the ign being left on overnight had weakened the module in some way and it failed at a later stage.

Did both modules fail or only one?

I had no spark on either coil, and I've got continuity between the plate and white wire, as well as the plate and black wire. So I believe that both did fail. I've also got some white stuff that looks like corrosion that's barely visible under the 1-4 pickup.

[Suzuki_Don]

I am surprised others have not chimed in. If it were me I would fit the new Dyna S unit, make sure battery is fully charged and try it again with generator wires disconnected in case it is over charging. But I am the kind of guy that is prepared to take a risk to get my bike going even at the risk of burning something out.

Your decision.

[mike_of_bbg]

Don, I really don't know that there's any good option there but to try it. Well, this is a pre-80: did you keep the points? If it were me I might put them back in long enough to run it and ensure that the charging system is sorted. They don't need to last long, but will be more resilient to excessive voltage.

[Killer2600]

I had no spark on either coil, and I've got continuity between the plate and white wire, as well as the plate and black wire. So I believe that both did fail. I've also got some white stuff that looks like corrosion that's barely visible under the 1-4 pickup.

I don't own a Dyna S nor am Dyna's tech support but with the ignition powered up I would expect the black and white wire to show a connection to ground. It could even possibly show a connection to ground when unplugged/powered off.

[Pendulum]

I am surprised others have not chimed in. If it were me I would fit the new Dyna S unit, make sure battery is fully charged and try it again with generator wires disconnected in case it is over charging. But I am the kind of guy that is prepared to take a risk to get my bike going even at the risk of burning something out.

Your decision.

I don't really have much choice, unfortunately.

Don, I really don't know that there's any good option there but to try it. Well, this is a pre-80: did you keep the points? If it were me I might put them back in long enough to run it and ensure that the charging system is sorted. They don't need to last long, but will be more resilient to excessive voltage.

The bike had a Dyna III when I bought it, so no points. The reason I upgraded to the S was because the III fried when the original R/R went out.

I don't own a Dyna S nor am Dyna's tech support but with the ignition powered up I would expect the black and white wire to show a connection to ground. It could even possibly show a connection to ground when unplugged/powered off.

According to Dyna tech support, if there's continuity between those wires and the plate, it's probably fried. I was told this by 2 different tech support guys.

[Killer2600]

According to Dyna tech support, if there's continuity between those wires and the plate, it's probably fried. I was told this by 2 different tech support guys.

Well the keyword is "probably" and if they want to warranty it or fix it for free then that's on them. If they want to charge to fix or replace it, in my opinion, it better be broken.

I'm a bit skeptical and don't trust the words of tech support or salesmen

[Pendulum]

Well the keyword is "probably" and if they want to warranty it or fix it for free then that's on them. If they want to charge to fix or replace it, in my opinion, it better be broken.

I'm a bit skeptical and don't trust the words of tech support or salesmen

Yeah, I won't be doing that any time soon either. My brand new Dyna S showed similar specs between the output wires and mounting plate.

I figured out the problem... My ignition fuse was partially blown. I was only getting 5v at the connection for the Dyna S.

[mike_of_bbg]

Glad you got it sorted. I found your issue vexing as well. The Dyna S is very well known for its reliability. The impedance through the pickups demonstrating a bad Dyna seemed rather sketchy to me as well: the idea of the ignition is to let ground through UNTIL it's time to fire the plugs.

[Pendulum]

Glad you got it sorted. I found your issue vexing as well. The Dyna S is very well known for its reliability. The impedance through the pickups demonstrating a bad Dyna seemed rather sketchy to me as well: the idea of the ignition is to let ground through UNTIL it's time to fire the plugs.

Yeah, it sucks that I spent the $150 on a new part, but at least I have an extra now. I could just really use the money right now due to my rapidly changing living situation. Off topic, but... Roommates are never a good idea. I'm never cohabiting with anyone ever again.

[mike_of_bbg]

Will they take it back if it remains unopened/uninstalled?

You might be able to sell it in the parts for sale board, though the going rate for new ones is really about $120 via eBay.

Yeah, it sucks that I spent the $150 on a new part, but at least I have an extra now. I could just really use the money right now due to my rapidly changing living situation. Off topic, but... Roommates are never a good idea. I'm never cohabiting with anyone ever again.

[Pendulum]

Will they take it back if it remains unopened/uninstalled?

You might be able to sell it in the parts for sale board, though the going rate for new ones is really about $120 via eBay.

It's already opened and installed. I'm sure if I threw a fit, I could return it but meh. The shop I bought it from has been good to me, and it's my fault for not testing thoroughly enough before buying.

Besides, if I return it then I'll need one in a week lol. Or, I'll be broken down on the side of the road in some small town at 3 AM in the rain on a cross country trip. That's just how my luck has been lately.