Backward Compatible Transducer Question

I have an Interphase 20/20 fish finder, depth, temp and speed box from the late '80s/early '90s. *It is connected to a thru hull transducer that I'm having a heck of a time getting a manufacturer or part number off of. *The Interphase box manual says it uses a 200k Hz transducer. *All works fine on the box, but it is very difficult to read the CRT display in the sun. *I'd like to replace the box with a combo GPS, depth, speed, fish unit or just a depth digital read-out unit. *I've combed the Interphase web site, etc. for compatibality info without success (don't have a part number!). *Any experience with wiring up an old ducer to a new unit out there? *Are there Internet resources I'm missing? Any and all help appreciated. Thanks!

Why not try calling them. The net is great but it also is often just advertising and no real depth to the info offered. Not much better than some of the printed brochures.

Sometimes the web pages have a technical question facility, a contact us box , or you can get a tel.# to call and talk to a tech.

I have a similar issue where I'm using an old Lowrance X70 monochrome depth sounder I inherited with the boat, which I moved upstairs when I installed a Lowrance GPS/depth colour combo down at the main helm. The old one is very good, in that it does all I need up there, and because it has a good through-hull transducer, and operates on 192 Khz. I can't really see why one should not be able to use that same transducer for a new(er) Lowrance unit which sends at 200KHz, but there appears no alternative to yet another hole in the hull, because the plugs are different. Has anyone just rewired a newer unit to use an older transducer..? The manufacturers just say it can't be done, but not why. I suspect they just want to sell another new transducer. Anybody..?

Funny I just read a thread about a guy that had done it quite a few times.* If the boat is in the water....as long as you can get the 2-3 wires correct (usually a power, ground, possibly shield (if shield and no black wire the shield is used as ground).

He did it with a generic 200hz transducer and a new Raymarine digital depth.

Worked for a marine electronics firm for 4 years and know that tansducer cable is spliced all the time...but as to a old transducer with new eqipment I'm not positive...but as I said...others say it's possible as long as the freq is the same

I might try it in a similar situation...but if the boat is out of the water then I would definitely install a new transducer.*

Airmar makes the transducers for about every manufacturer. If you call them, you will have to use a phone and not your computer, and give them the original model, they will tell you if that transducer is compatible with any other displays, etc. Chuck

I don't think it is worth the effort.

*I would say time to up grade.

I have a garmin 4208 that is plug and play and does all you want.

Plus it has the feed for an engine room camera.

Just plug and go.

some times the best laid plans just arn't worth it.

It will cost you a boat buck but doesn't everything on the boat.

SD