Magic smoke escaped

[Capt]

Okay that magic smoke from my Cessna type split rocker master switch decided to escape during start, the result? All my "EI" engine instruments are dead! Everything else elect works inc starting, spent hours chasing the fault to no avail, might be time to take up sailing! -
It's a birds nest under my dash (I didn't build the beast). All guages have circuit breakers, none popped, wish I could crawl under my panel, 6ft 220 lbs at my advanced age means I'd never get up again! There must be a hidden inline fuse/s somewhere buried, trouble is if I find same what was the original reason why it/they blew? Switch appears fine (I Pulled it apart) That's the million dollar question! No Xmas flying for me....sob sob sob

[rvdave]

What model is this? Is there a subpanel you can take off?

[rleffler]

Unfortunately, my only recommendation is to start tracing every wire and create a schematic. It's a royal PITA. But having an accurate schematic is a necessity in my opinion. It will also help the resale value.

Start by pulling your EI gear and testing the voltage on the power pin. Then trace that back to the power source.

I may be older and I am a pound or two heavier. I've spent more time under my panel that I care to admit troubleshooting an issue with my GTN650 that turned out to be an error in the install manual. (the manual error has been fixed) At least with my RV-10, if I pull the front seat and stick, I can lie relatively flat.

One last piece of advice, since most of us old farts need bifocals, get a a pair of glasses that has your reading prescription on the entire lens. You will be looking out of the top of your glasses a lot.

[PilotjohnS]

For those of you who do not have a schematic for your plane, I would recommend you do it now, before something smokes or something breaks in the field. Once the schematic is done, make sure it is what you want. Otherwise you are trusting in blind luck some idiot didnt wire your panel.

Sorry for the motherhood statement.

[Carl Froehlich]

Great opportunity to pull the panel along with the wiring and just start over. When you do establish some objectives:
- You end up with full documentation of what wire is on what connector. I find this a superior method to wire labels.
- Design the panel to come out. NEVER crawl under the panel.
- Dump the 1960 Cessna split rocker switch. Why this lingers amazes me.
- If you have your running list of panel upgrades now is the time. A new panel is just a ~$25 piece of aluminum from Van?s, some time cutting holes and paint.

When you are done you have ?your? panel and you know everything there is to know about it.

Carl

[az_gila]

Originally Posted by rleffler

Unfortunately, my only recommendation is to start tracing every wire and create a schematic. It's a royal PITA. But having an accurate schematic is a necessity in my opinion. It will also help the resale value.

Start by pulling your EI gear and testing the voltage on the power pin. Then trace that back to the power source.

.....

That is the short term answer to get you flying again.

Don't forget to check the grounds and look for wires rubbing on sharp edges that can cause a short in the middle of a bundle.

As Bob says, just trace it out with a voltmeter, cut open the tyraps if you have to, as you follow wires. You know(?) the switch has power, and you then need to see if it gets to the EI unit (probably not).

[JonJay]

The only thing the Split Master should control is your Master Relay and ALT Field.

If everything else works as you say, Starter, Radios, Lights, Flaps, etc.... I would suspect that the builder wired all of the EI gauges to one breaker or fuse and that gives you a place to start.

The fact that the Split Master "smoked" doesn't make sense to me that you would only lose a portion of what the Master Relay feeds. Something is amiss.

This is assuming the builder wired the Split Master as it should be, and did not take a sort cut and use it to control other loads, like the EI stuff. That wouldn't be good practice.

[Mike S]

Does the EI unit have an internal fuse?

[snopercod]

Originally Posted by JonJay

The only thing the Split Master should control is your Master Relay and ALT Field.

Correct me if I'm wrong, but doesn't the BAT half control the master and the ALT half control the alternator field (through a circuit breaker)? Maybe I'm misunderstanding what you wrote.

[Mike S]

Originally Posted by JonJay

The only thing the Split Master should control is your Master Relay and ALT Field.

Originally Posted by snopercod

Correct me if I'm wrong, but doesn't the BAT half control the master and the ALT half control the alternator field (through a circuit breaker)?

Methinks you are both saying the same thing.