blaplante
Well Known Member
Throwing this out to see if anyone has seen such a problem before.
GNC420 GPS+COM. Had it powered up on the bench via the primary (GPS) P4001 connector. Worked fine, found position, etc.
Installed in plane. No go! Power up, nothing, blank screen.
After much futzing around I discovered if I disconnect the P4002 (25 pin D COM connector)... THEN the GPS powers up!
I double checked that there is power on pins 11&12 of P4002, and ground on pins 21,22.
The only other thing odd is that this is a 28V box that came with a 14->28 volt converter from the avionics shop. The converter is rated for plenty of output amps for the purpose, especially as the problem is manifesting at power-up... not transmitting. So I really don't think the converter is the problem.
Hoping g3expert or someone can give me some guidance!
GNC420 GPS+COM. Had it powered up on the bench via the primary (GPS) P4001 connector. Worked fine, found position, etc.
Installed in plane. No go! Power up, nothing, blank screen.
After much futzing around I discovered if I disconnect the P4002 (25 pin D COM connector)... THEN the GPS powers up!
I double checked that there is power on pins 11&12 of P4002, and ground on pins 21,22.
The only other thing odd is that this is a 28V box that came with a 14->28 volt converter from the avionics shop. The converter is rated for plenty of output amps for the purpose, especially as the problem is manifesting at power-up... not transmitting. So I really don't think the converter is the problem.
Hoping g3expert or someone can give me some guidance!
