charybdis55
Member
I have an old Autohelm 4000 model Z077 on my 11.5m sail boat. It has worked perfectly for 3 years but within the last few weeks has started to go wrong.
Initially, while in Auto mode, it would take itself to Stand By accompanied by the button push confirmation beep. Although it’s only happened twice, a bit worrying on a long night passage!
The wiring inside the unit is solid as is the plug connection.
Subsequently, the unit has become erratic in operation and will suddenly turn hard to port or starboard for no apparent reason. Sometimes the off course alarm sounds but I didn’t measure the time interval between going off course and the alarm sounding as I had to return the unit to stand by and open the wheel pilot clutch to keep on course.
I completely dismantled the unit to check for anything that may cause erratic behaviour but couldn’t find anything untoward. At some stage in its life one of the motor drive transistors has been replaced but, as the unit works perfectly in Standby mode and +-1 +-10 Port & Starboard in Auto mode, I assume the motor drive transistors are ok. I’m not sure if transistors have an in-between state of working and not working but, I’ve ordered 2 x BDW94B PNP and 2 x BDW93C NPN transistors just in case.
I removed the flux gate compass and measured the resistance of each coil, all 8 showed a resistance of 3.3 ohms.
There have been no significant changes in what’s stored in close proximity the unit and I’m at a loss what could be the issue.
I like the unit for its simplicity and it does exactly what I need. Could anyone on this forum offer advice on what I could check with a multi meter, basic electronic knowledge and a soldering iron?
Alternatively, does anyone know where I could send the unit for repair?
Initially, while in Auto mode, it would take itself to Stand By accompanied by the button push confirmation beep. Although it’s only happened twice, a bit worrying on a long night passage!
The wiring inside the unit is solid as is the plug connection.
Subsequently, the unit has become erratic in operation and will suddenly turn hard to port or starboard for no apparent reason. Sometimes the off course alarm sounds but I didn’t measure the time interval between going off course and the alarm sounding as I had to return the unit to stand by and open the wheel pilot clutch to keep on course.
I completely dismantled the unit to check for anything that may cause erratic behaviour but couldn’t find anything untoward. At some stage in its life one of the motor drive transistors has been replaced but, as the unit works perfectly in Standby mode and +-1 +-10 Port & Starboard in Auto mode, I assume the motor drive transistors are ok. I’m not sure if transistors have an in-between state of working and not working but, I’ve ordered 2 x BDW94B PNP and 2 x BDW93C NPN transistors just in case.
I removed the flux gate compass and measured the resistance of each coil, all 8 showed a resistance of 3.3 ohms.
There have been no significant changes in what’s stored in close proximity the unit and I’m at a loss what could be the issue.
I like the unit for its simplicity and it does exactly what I need. Could anyone on this forum offer advice on what I could check with a multi meter, basic electronic knowledge and a soldering iron?
Alternatively, does anyone know where I could send the unit for repair?
