St60 depth fried

[Atlantic Salt]

All my gauges are Raymarine ST 60 vintage. On Saturday, we smelled and saw smoke. I quickly isolated to an instrument and shut down the power to them. When we docked, about 30 minutes later, we isolated it to the depth gauge. I just took the gauge a part and the board is badly fried and the sea talk plug was melted and fused to the back of it. Has anyone seen this before or do you know why it would happen or what caused it?

[senormechanico]

I have not seen that problem, but suspect the cable connector shorted internally.
I'd bet the gauge is OK.
(retired electronics tech)

[Atlantic Salt]

The actual transponder should be OK - I hope - but I can't see how the gauge is. I took apart and one of the metal pin connectors on the board is completely melted and the board and circuitry in that area is charred. Thanks for the reply - it all helps!

[smac999]

how big was the seatalk fuse feeding all the gauges?... it should only be a couple amps. and probably should have blown.

[87Catalina34]

check your battery ground , if its loose, it could cause an overvoltage in the line. mine just fried last week, for these reasons. mine was connected and powered directly by the seatalk backbone. it still fried, auto pilot and chart plotter and all other instruments were not affected

im hoping to be able to fix mine.

[GordMay]

This might help.
Raytheon ST-60 Digital Instruments SERVICE Manual
➥ http://www.olajedatos.com/documentos...e%20Manual.pdf

[transmitterdan]

A picture might help.

There are a few possibilities. It’s possible that a protection device failed on the board. Seatalk is often wired with too small wire for the length of the network. It is possible that the resistance of the power wires (red/black) is too high and the fuse could not be blown open by a fault on the board. So it cooked the board and connector.

It would be prudent to check all the other seatalk plugs for any damage. Also, check that the fuse at the power injection point on the seatalk network is properly sized.

ST-60 depth units often come up for sale on the CF commerce section. Also, check eBay as well as local boatyards. Many boaters are replacing ST-60 systems with newer instruments so there are likely used depth units around if you do a search.

[Atlantic Salt]

This process has been enlightening. There was no fuse in the circuit. Now I have a five amp fuse which is what Ray Marine recommends. However, there are two instrument switches on my electrical panel and they each power on the instruments. one or the other can be turned on or both can be turned on at the same time and under any of those conditions the instruments are on. I put the fuse in The circuit are usually use. I am about to trace the second circuit to see where it enters the network. Is it normal to have these instruments powered by two circuits?

[smac999]

No yiu can’t have that. Otherwise if both are fused at 5a. Yiu now have a 10a fuse.

often the auto pilot powers them. But if it dies. you should choose either the pilot or a direct power source. And get rid of the other.

A seatalk to seatalkng adapter will also inject power from a seatalkng network to seatalk. Same thing. Either power the seatalk or seatalkng network. But not both. Or isolate power between them by cutting wire.

[Atlantic Salt]

Good suggestions. Not sure I agree with the 5+5=10 amp fuse comment. I think if there was over 5 on either circuit then that fuse, or both, would blow. However, I don’t think the way it is set up now is right and I will have to investigate further.

[transmitterdan]

Originally Posted by Atlantic Salt

Good suggestions. Not sure I agree with the 5+5=10 amp fuse comment. I think if there was over 5 on either circuit then that fuse, or both, would blow. However, I don’t think the way it is set up now is right and I will have to investigate further.

The 5+5=10 is right if both switches are on. This is not the right way to power a Sea Talk network. Try to get ahold of a Sea Talk instrument installation manual. It will describe the right way to wire the power. Try raymarine.com for tech advice and downloadable manuals. ST60 is in the discontinued products section.

Having no fuse in a circuit is a fire waiting to happen. Good job finding and fixing that. Look elsewhere for crimes against electricity because it’s rare to find just one thing wrong.