Autohelm 6000 Bowing a Fuse

[ErikFinn]

Originally Posted by Capn Dan

Erik,

Just pull the bad transistor and diode and do not replace. Now try powering up the computer. If you have no other problem on the board, the control head will display. If it works, replace the bad diode and transistor.

Dan

Thanks Dan,
will try that!

[ErikFinn]

Just a quick update, was in contact with Premier Farnell Plc, a big electronics distributor; they had 2 (two) transistors of my model available in Malaysia, more than 1300 in UK, I ordered the last two in Malaysia...
Today going to town to hunt for diodes and some "clever guy" to solder the pcb, let's see what happens...

[ErikFinn]

Surprisingly managed to buy the diodes and a condenser from an electronics supply store in Penang, AND found a TV repair shop who will do the checking and soldering of the basic components for about 8 USD. I can't believe my luck!
I just hope the rest of the components are ok and that there's nothing else wrong with the board. The transistor is arriving from Singapore in 2-3 days. So by the weekend I should be able to finally see if this thing was fixable or not.

[ErikFinn]

Well, I had the computer back from the TV-repair shop, and put everything back together again and the fuse no longer blows. However, something is still wrong. When I switch on the power, the control unit beeps shortly, and what looks like three C's flash on the display once shortly but only the backlight remains on. No digits or letters. When I then try to operate any of the buttons, I do get beeps from the red ones, not from the black ones, and nothing happens with the drive unit, ie I can't get the drive unit to move the rudder. I think it should move after pushing "stand by" and then pushing the course buttons (-1, -10, +1, +10) . I tested the drive unit earlier by overriding the computer and applying power to it directly and it worked. So it looks like the drive unit is not getting commands from the computer. I don't know what to do next. Does this imply another fault with the computer? Or is it likely to be something simple? Any ideas? At this stage should I just forget about this old computer and give up, and just get a new computer..?

[Capn Dan]

Erik,
Unfortunately, it is probably not something simple and is another fault on the circuit board. So, try to find a replacement computer or bite the bullet and buy a replacement.
Dan

[Searanger50]

Hi,
Sorry I haven't managed to get on the site for a few days. The most likely scenario is that TR1 and its circuit components were damaged by another fault rather than the fault itself. If the manual tells you the correct input and output values you could check for the correct input and output voltages at various points on the circuit. This may point to where the fault lies and allow you to isolate it. Unfortunately modern electronics with integrated circuits (ICs) are not really designed to be fixed (I started off on valve sets as an electronics engineer in the RN in 1975). If this doesnt help then as Capn Dan says you may have to surrender.
Sorry I can't be of more help. Kevin.

[ErikFinn]

Thank you Dan and Kevin for your excellent help! :-)
So close and yet so far.. Well at least I've learned a lot, Have to think now what to do..

[salpa1907]

I have autohelm 6000 type 1 (probably) and course computer is z049. I will explain my problem in aan other title. But I'm curious about end of your story.

[ErikFinn]

Salpa, I wasn't able to fix the computer. I believe the boat has had an indirect lightning strike that fried some of the components, memory and/or processor as I've heard these are the most vulnerable ones. So a bridge too far. Haven't bought a new computer computer yet. I have a wind pilot and considering using just that, as there is no electronics involved and I'm not too keen to experience another electronics frying lightning strike.

[dlymn]

Hi Erik
Would that service manual have the wiring to connect a remote control unit by any chance? My outside control unit is about as far away as you can get from where I sit managing the sheets. I thought that I might be able to knock up a simple remote unit assuming that the guts of the original unit was just a series of switches.
David

[JackTrac]

Originally Posted by ErikFinn

Something caught my attention and I need to ask for advice.
I looked at my "Autohelm 6000 Service Manual" and the TR1 listed for my Z051 Course computer is "NPNBDW398".
However, looking at my pics on posts #20 & #21 the TR1 has the print on it: "SGS 28737 BDW93B".
To me these don't seem like identical parts or am I wrong?

See pic from the Service Manual under "7.5 AH 6000 TYPE CR COMPUTER PCB (Z051,Z052, Z062, Z063)" - page 76 part number listing:

Noticed on the Service Manual pcb circuit diagram the TR1 however seems to be labeled as "BDW93B" (the old photocopy quality is poor)

Is this just a case of different part numbering standards?
What's the explanation? Same part different names, or do I have a wrong part on the pcb, or is my service manual incorrect?
When I hunt for the part which part number should I ask for?
-Erik

Anyone still have the service manual for the Autohelm 6000 Z051 or the schematics?
I'm trying to repair an autopilot of the same kind.