pa38112

pa38112

Well Known Member
Does anyone have an Exp Bus 2 with the external over voltage indicator light installed? When I connect the indicator LED it trips the overvoltage circut and lights up. - The manual says that the light should go out in an over voltage condition. Am I reading something wrong, and what would cause the lamp to trip the over voltage circut ?
 
Without seeing anything, just a guess:
LEDs only go one way, one lead to +, one to -. Make sure they aren't reversed.
 
I have an EXPBUS 2 but I have no documentation mentioning an OV light.

Mine connects to the EXP indicator panel with a ribbon cable. I have not been able to get any schematics for troubleshooting from them so if it ever goes bad I will probably end up pitching the whole thing. I purchased one very early on in the build, about 12 years ago and regret it.
 
I did not know that about LED's - you lean something new every day ! - Does the fact that it is lighting up mean that it is correct ?
 
Probably. LEDs will only light when the voltage polarity is correct.

I does not make sense for the LED to cause the OV. It may not connected correctly and you are pulling down the voltage somewhere else which the board sees as an OV. Your best bet is to call Control Vision and get some tech support.
 
Thanks - I have tried Control Vision, but they have not answered my e-mails. I will try calling, but have found them to be less than suportive of this thing. -I do know it is tied into the indicator light, though, because if I unplug the light the over voltage trip-out condition goes away.
 
There are many EXP Bus systems out there working just fine. However, when it comes to electrical system troubleshooting, it puts you at a severe disadvantage.
I yanked mine out over the last week and reworked my entire power buss and secondary protection as a last attempt to diagnose a electrical gremlin affecting my Alt. Field. I will post separately my experiences. In fairness, I do not know if the problem is the EXP Bus, and I may never know.
That is exactly why I don't care for the product.
 
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What are you doing with your old unit ? - I would be interested in having a spare and test unit, but not at the standard price.
I'm currently having an Alternator Field issue on top of the LED for Over Voltage Protection. That is one of the reasons I'm installing the remote LED; to be able to know if that is why the Alternator stops putting out current.
I would be very interested in hearing about your issue and what you have tried/found
 
pa38112 said:
What are you doing with your old unit ? - I would be interested in having a spare and test unit, but not at the standard price.
I'm currently having an Alternator Field issue on top of the LED for Over Voltage Protection. That is one of the reasons I'm installing the remote LED; to be able to know if that is why the Alternator stops putting out current.
I would be very interested in hearing about your issue and what you have tried/found
Click to expand...

If my problems go away after the rewire I intend to throw it away. I am not taking the chance that somebody else has to deal with it. Since I have now rewired the entire power distribution system, even if the symptoms go away, I will never know if it was the EXp or something else in the wiring.
If my problem still persists, and I am able to find and fix the issue, then I will sell the unit for a very reasonable price.

Two symptoms I have are charge current fluctuating and OV tripping on hot days only. I changed alternators from the Nippo to Plane Power. ( The Nippos does not have OV protection, the Plane Power does). Same symptoms. I isolated the Alt. Field directly off of the EXP buss onto a resetable separate breaker and rewired the entire Alt. Field circuit using #16 instead of #18. No change. I fabricated a scoop for my Alt. blast tube to make it more effective and put a heat shield on the exhaust in that area. I spent hours disconnecting instruments, radios, devices, checking grounds, resistance through the system, you name it. Could not find anything.

I should be able to test fly in a few days and will write up my experience through this whole thing.
 
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