Rob wrote:
I recived a Lowrance Fish Lo-K-Tor "Little Green Box" model 505B from a
friend. I believe it is a 1960s or 1970s vintage fish finder although I
know very little about these. It appears to work, the disk spins, but the
flasher bulb is broken. It appears to be neon bulb about 1 inch long. I
was told by someone that it probably operates at 600V. I did a search on
DigiKey and so no good replacement. I have also searched for schematics on
these fish finders on Google and found nothing. Does anyone know any
details about these bulbs? What operating voltage? Are there any
practical replacements?

Any insight would be greatly appreciated.

- Rob

Hi Rob...

Do you mean the bulb is broken as in physically broken, or as in doesn't
light?

If you're meaning it doesn't light, it's far, far, far more likely that
the transducer is gone. And remember, it needs at least a reasonable
facsimile of looking through water to operate.

On the other hand, if you mean it's physically broken - it's been a
long time, but I suspect it's just an ne-51h. If you do decide to
try one don't forget to put a resistor in series just in case.

Or, if you'd rather be safe than sorry, try calling fish-lectronics,
(763) 571-1277. They are/were in Minneapolis, USA, and might be willing
to tell you for sure what it is. Maybe even sell you one if it turns
out to be unique.

Good luck, good fishing, and take care.

Ken