Need help with Narco LORAN LRN 840

Benjamin Gawert wrote:
I got an old NARCO LRN-840 LORAN-C that I want to reanimate. Sadly I
only got the unit itself, no manuals or cables. What I need is a pinout
of the rear card-edge connector and informations about what voltage it
requires etc. If someone has a manual as pdf or any other electronic
format it would be great if he'd mail that to me.


I have an LRN-820, and the pinout may be the same. Looking at the back,
top row of pins (L to R) are 1-12; bottom are A-N. GND is H & J (there
is no I pin). +14/28v is pin 7. Use a multimeter to verify. GND will
be a dead short to the case. Measure +V in to GND: with multimeter set
on high resistance, turning switch on should cause the meter to show an
increasing resistance reading until an electrolytic capacitor fully
charges. Feed in +V thru a 2-3 amp fuse for insurance. Current draw on
the 820 is .5A at 14V; .25A at 28V.

It probably also requires an amplified antenna. Did you get a little
amplifier box which is inserted (near antenna end) in the coax to the
antenna?

Fred F.

TxSrv schrieb:

I have an LRN-820, and the pinout may be the same. Looking at the back,
top row of pins (L to R) are 1-12; bottom are A-N. GND is H & J (there
is no I pin). +14/28v is pin 7. Use a multimeter to verify. GND will
be a dead short to the case. Measure +V in to GND: with multimeter set
on high resistance, turning switch on should cause the meter to show an
increasing resistance reading until an electrolytic capacitor fully
charges. Feed in +V thru a 2-3 amp fuse for insurance. Current draw on
the 820 is .5A at 14V; .25A at 28V.

Thank you very much! This was the information I was looking for...

It probably also requires an amplified antenna. Did you get a little
amplifier box which is inserted (near antenna end) in the coax to the
antenna?

Sadly, no, just the base unit. But it's not for use in an airplane any
more but just for the fun of it, so that's not a problem at all.

Thanks again!

Benjamin