Autohelm ST2000+ Terminally Ill?

Appledore

Appledore

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Hi All,

Following on from my recent post about me destroying the Bulgin connector on my AH 2000+ unit, I now find that it won't power up when I connect the pos and neg wires to the power supply.

I read somewhere yesterday that if the pos and neg wires are wrongly connected, that may cause irrepairable damage to the unit. I am arranging to take the unit to a local outlet, but in the meantime does anyone here have any thoughts on this? Have I killed it completely? I'm willing to spend some money on it 'cos I can't afford almost £600 for a new one?

thanks

Geoff
 
It should be polarity protected, so connecting it up wrongly should simply mean it doesn't work, rather than destroying the electronics inside it.

Are you certain you now have the power supply correctly connected?
 
Pretty certain as I checked the supply with my voltmeter, that's how I found the voltage to be negative on what I thought was the positive terminal. Connecting the 2 x pos and 2 x neg wires together in a block does nothing! Perhaps I'll try it again when I go to the boat again. Thanks for the 'positive' feedback re the protection. At the price they are, it should be protected!
 
Appledore said:
. Connecting the 2 x pos and 2 x neg wires together in a block does nothing!
Click to expand...

???? There are only two power wires to connect, +ve and -ve. The other wires to the plug are data connections. Not sure from memory, but aren't the power wires brown and blue and thicker than the data wires which are white, green and yellow? Ignore these.
Edit, sorry, just re-read your post, I might have misinterpreted your meaning!
 
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The Service Center at Wareham will have a look and either sort it or let you know how much you have to pay for about £60.
I'm about to send them my old one. I wish I had known that Cactus sold at that price when I bought my replacement for £439 from Marine superstore who have since increased their prices.
 
NickRobinson said:
Mine have all had bridge rectifiers so would work whichever way connected to power. (not that I took liberties to test the theory.)
Click to expand...
Sorry but this is not true, even if it had a bridge rectifier it would not enable the autopilot to work with wrong polarity.
The only way a bridge rectifier could enable this statement is if the autopilot was connected to an AC supply, and that is not going to happen in a boat.
There is a power diode on the circuit board inside the Raymarine ST2000+ in series with the 12 volt power. The purpose of the diode is to ensure that if the pilot is occidentally connected the wrong way round, the diode will block the current into the pilot as current can only flow one direction through a diode. No harm should come to the pilot as a result of a reverse connection on the power supply cables.
The same may not be true if you connected the power up to the data cables inadvertently.
Mike
 
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crackle said:
Sorry but this is not true, even if it had a bridge rectifier it would not enable the autopilot to work with wrong polarity.
The only way a bridge rectifier could enable this statement is if the autopilot was connected to an AC supply, and that is not going to happen in a boat.
There is a power diode on the circuit board inside the Raymarine ST2000+ in series with the 12 volt power. The purpose of the diode is to ensure that if the pilot is occidentally connected the wrong way round, the diode will block the current into the pilot as current can only flow one direction through a diode. No harm should come to the pilot as a result of a reverse connection on the power supply cables.
The same may not be true if you connected the power up to the data cables inadvertently.
Mike
Click to expand...

A diode bridge would certainly allow connection to a DC supply of either polarity
 
Yes sorry, looked at the circuit again, I stand corrected. But a bridge would give approximately twice the volt drop.
Mike
 
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