RGS dead- Witt question

[Reggie3cl]

OK, so I go to start up the RGS for the first time since October: Dead as a doornail.  Takes me back to my 180 before I fitted the IIS, ho hum.

Anyway, checked the spark first with a spare plug earthed to the head- nowt, nil, nada, bupkis. 

Haven't touched the unit or its wiring over the winter, but it doesn't seem to have power.  I'm sure I'll find something loose somewhere, perhaps from when I fitted the relays for the lights or summat, but  looking at the trigger unit I was wondering if you can actually see the light on the optical trigger when the DMC is powered up?

 

[sfcpiet]

Reggie,

Try cleaning the sensor.  Condensation and dust can block it to the point that it fails.  Just run a clean tissue through it.

If all else fails, fit a new optical sensor.  They very rarely fail completely.  Keith might be able to help you out, if not, give me a shout.

piet

 

[breganzane]

You got power to it?  If you've still got the original fuses they're fabulous at developing high resistance joints occasionally.  I'd look for something like that before suspecting the opto.  Check for 12V at box and coils. Twiddle your fuses, check your earth points.  Ignition switch and kill switch also.

I still remember seeing the fuse box of John Wilson's old Alfa Sud (same ceramic type fuses) - every fuse was soldered in!  He simply carried a 12V soldering iron in the event one blew and he needed to change it.

Cheers
Steve B

 

[Dellortoman]

Check for 12V at box and coils.

Voltage at the ignition box and coils won't necessarily reveal whether there's a high resistance at the fuse. Voltage drop is current dependent so you need the system to be under normal load conditions. If there's bugger-all current flowing, it'll still show close to 12V. Once there's a current draw, the voltage will drop. I got caught out by exactly that scenario on my Ducati. There was 12V at the ignition unit without the engine running, but the bike would barely start and wouldn't run properly. It wasn't until I actually measured the voltage with the engine running that I found a significant voltage drop. Checking the resistance across the fuse I found a bunch of Ohms that shouldn't have been there.

Cheers,
Cam

 

[Reggie3cl]

Thanks for the suggestions gents, but inevitably it was, ahem, user error.  When I fitted the relays for the headlight I noticed some redundant wiring so I removed it.  Seems not all of it was redundant.

I figured out there was no power pretty quick- hence my question about seeing the light at the trigger unit but all fixed now.  A little LED indicator on the front of the box as per the IIS would be nice.

Still, at least I now know that I'm going to have to spring for a new battery soon.