Autohelm Personal Compass playing up with new batteries

[iainhu]

Okay, new batteries arrived from batteries4you a day after ordering as suggested and measure 6.0V. This is therefore new set #3.

Insert into Personal Compass and...

All segments of display light followed by --- display and ready to go. This is looking good.

Take one bearing okay. Take two bearings okay. Take third bearing and I have 1UU all in half-height chars. Looking across the display rather than directly at it, it reads as 988, but the top of the display is feint so straight on (as you'd normally view it) you only see the bottom of the display, hence 'half-height' 1UU. This is not so good :-( Attempts to switch on backlight (MEM + TIMER buttons together) does nothing. So the unit seems to be in some kind of locked-out state.

Remove batteries, short internal terminals (you never know, this might help), reinsert batteries and...completely blank. No sign of life at all. Repeat a few times, and every time the unit is utterly dead.

Remove batteries and check voltage...5.5V...which is about the same as new set #2 and means these newest batteries, set #3, have gone from 6.0V to 5.5V in the space of about 5 mins after insertion in the personal compass. Is this the issue?

In fact when I first changed the batteries (to new set #1) everything seemed to work, it was only when I tried some time later to use the unit for real in Greece it 'played up' working and not working at random.

Anyway, having tested the battery voltage (5.5V together), reinsert the batteries, press the red button and get an 'illegal' display of something like UUU followed by all the segments and then dead again.

I am now wishing I'd bout the 12 pack of CR2025 from batteries4you (as it only cost £5-something!) so I could continue to experiment with further sets of batteries. Meanwhile I'm building up a good stock of 'old' CR2025 batteries ;-)

I'll experiment through the day, but after initial hope it looks like I'm back in the same place as before and the 'fresh batteries' argument may have been disproven. Maybe it's a fault in the compass that is draining new batteries really fast, hence they initially work and then go into unpredictable behaviour due to the reduced voltage batteries?

.../Iain

 

[iainhu]

Further test...

Warmed batteries. Cleaned batteries and unit terminals with meths. Checked battery voltage which was 6.1V combined. Inserted into compass, pressed red button and in the top of this display I got 000, the 0s being the top of an 8 (not proper zeros) with a sideways T in the degree and bearing count spots, e.g. not working at all.

Remove and recheck batteries which are still 6.0-6.1V. This suggests the unit is misbehaving even with a 6V supply which rather kills-off the 'bad battery' theory and the 'fingers on batteries' idea too...which is a great shame as I seem to be back to the strange position of an apparently perfect unit, which can work at times, but mostly wants to play different versions of not working...odd siaply chars, all display lit, unti completely dead etc.

Still no word from query to Raymarine :-(

 

[boguing]

That's a shame.

I can only suggest taking it apart to see if there is any water damage.

Just taken mine apart (sharp blade between the rubber and case to crack the first bit, then all the way round with a screwdiver. The cases are held together by glued pegs, which all break, so epoxy needed to refix.

Mine shows no sign of any leaks or corrosion.

Worth a try though because I don't think that there's much chance of it fixing itself.

Mine has no 'holdover' memory ie. Take the batteries out and it forgets stored bearings.

So there does not seem to be any stored power on the circuit board, and that suggests that there is no point in shorting the terminals.

 

[iainhu]

Not (yet) certain about breaking it apart. The unit is little used, has never been wet and excepting the battery cover which is now showing signs of a coin being used to open and close it repeatedly, the unit looks as if it's just come out of the box. I therefore would put money on finding the same as you; no signs of leaks or corrosion. However...I do have to agree with your; "I don't think there's much chance of it fixing itself" diagnosis.

Have tried simply leaving new set of batteries #3 in the unit a few hours to see if it would 'stabilise' and start working, but several hours later it's still dead.

Have also hooked it up to a transformer giving 6.2V, verified the unit had 6V on it's contacts and still nothing. Could try it on 8V I guess but at the danger of blowing the unit and then it really would be dead! However, this all suggests it's not bad batteries which is a real shame...I was hoping for a breakthrough there.

So I'm back to wondering; Why did it go 'bad'. It was working, put away, taken out, carried to Portugal in hand luggage along with a laptop, and then when used didn't work reliably and showed 'BAT'. But after lots of messing with now 3 sets of new batteries, it is still not working reliably and (sometimes) showing BAT, so really, there's not a lot different to now and with new batteries as to on the return from Portugal and old batteries. So were batteries ever the issue? And if not, then why 'go bad' for no apparent reason?

So I am back wondering...what could have been the initial problem and so therefore, what could be a possible solution?

.../Iain

 

[Skysail]

Some years ago my Autohelm compass failed for no obvious reason - completely dead. Electronic components do fail, I bought another on ebay where they still fetch respectable prices. Some seller wants £99 for one, but you can pay much less than that.

A pity thay were discontinued.

 

[Cari bean Pie rat.]

Not familar with the equipment but is there a "reset" function like when you first set the units up ?
I think this battery is for the memory IC's and some data corruption could have occured.
It maybe in the volitle memories and all it needs is holding down the on button while pressing another button at the same time....just a thought.
Good luck.

 

[iainhu]

Some more bizarre behaviour by my Autohelm Personal Compass...

Last night I inserted the batteries and it all started up fine. I got 9 bearings without problem and then the display reverted to 000 and sideways T in the degree and bearing count segments (the 0 being the top loop of an 8 and the sideways T being a 3 without the top and bottom bars of the 3). I removed the batteries and left the unit.

Then this morning I reinserted the batteries and the unit started fine. I then took something like 24 bearings, switched to the timer, switched back to the memory recall...all working perfectly. Then put the unit down and about a minute later the display was blank and the unit won't come back to life.

This behaviour all seems terribly like depleted batteries...working until the battery voltage drops at which points things 'go wrong' or simply stop, yet numerous tests seems to suggest it's not batteries. Ahhhh!

 

[boguing]

I take it that you are confident that the spring contacts are clean and pressing hard enough on the batteries.

That would cause an on/off fault, but not the duff display you're seeing.

I don't think it's a battery problem now.

I can only think of two possibilities. A dodgy joint on the pcb or an actual component intermittently failing.

The lcd panel is held down onto the pcb with 4 screws. As far as I can see, the contact between them is of the clever rubber type.

And I'm not going to disturb mine!

My best guess would be that this contact is the most likely to show this behaviour.

 

[iainhu]

The spring contacts in the battery bay seem fine...clean, making good contact and the + (side spring) only appears to be making contact with the second battery, as it should to give 6V. I've also put a direct 6V supply onto the contacts although if they were making poor contact internally I'd not detect this of course.

Against the poor contact theory is why, say this morning, the unit performs perfectly for about 1-2 minutes, is then laid down, still working, and then 'goes dead' all by itself while sat undisturbed. That hints more towards an internal component working intermittantly - sadly as that doesn't seem very repairable, vs. a battery connection which with no movement or vibration, excepting heat movement, you'd expect to stay put, either working or not :-(

 

[iainhu]

And another thought against the battery contacts theory. The unit will, as just now, have batteries inserted, start up with a perfectly lit display of UUU, e.g. plenty of power but garbage on the display, and then (as now), flip over to the 'all display segments lit' (as it normally does for about 1 second on initial power-up) and stay locked like that, e.g. displaying that the unit has plenty of power...at least it's a perfect lit display...but the unit is simply unresponsive, locked on 'all display segments lit'. It won't light the backlight, timer or anything. The unit is entirely locked out.

So I guess I'm talking myself into the 'partially failed internal component' theory, only I then wonder; Why? Why when it was packed away dry and cool, would it 'just fail', or rather, just partially fail?

 

[iainhu]

There is no reset button...sadly...but then it doesn't need one...

Not familar with the equipment but is there a "reset" function like when you first set the units up ?

Sadly not...the unit is waterproof, floats and is 'minimal' in it's design and there's no reset hole, not even inside the battery compartment which is the only opening in the case.

But I've just reinserted the batteries and taken 100 bearings without problem and run the timer, can use the backlight, recall bearings from memory, continue running the timer, all working 100% AOK. And yet, unless I have just had some extraordinary Mon luck, the unit will lock up in a while, e.g. no corrupt data when I start using it, but it will at some point come to a grinding halt...at least on previous experience.

I was about to say I might leave the timer running to see if the unit will 'settle down', but looking down as I type, the timer which was working perfectly is now displaying 8:81"- BAT, only the second 8 is missing the top of the 8, e.g. garbage on this display. And it was just sat there with the timer running; which is why I don't think it's battery connector issue.

All buttons are now locked out, so no backlight, can't access the memory, go to the timer or anything.

An interesting thing though. I twice removed and replaced the batteries (to perform a reset) and each time the display came up showing 8:81"-BAT, e.g. there was a retained memory for the few seconds while I removed and replaced the batteries, only on the second time the unit started up with 8:81"-BAT and then blanked the screen within a second and went into 'dead mode'; totally unresponsive to anything now. Removal and replacement of batteries does nothing now (unit stays 'playing dead') and the unit will be like this for a few hours, then likely go again.

Batteries showing 5.5V after removal from unit but I suspect will recover...but I thought we'd (almost) disproved the battery theory? Now I wish I had a furth brand new set of batteries to try and this stage although I'm confident the unit would stay 'dead'.

 

[boguing]

I'm afraid you're on a hiding to nothing without taking it apart. I'm pretty ceratin that the lcd/board contact is the culprit.

No amount of successful startups would persuade me to trust it to work when I needed it. Dark night, GPS bust, take bearings, nip downstairs to plot and, oh arse, it's forgotten them again. You'll be back to writing each bearing down in case it packs up again. In which case you might as well be using an ornery hb compass that needs no batteries!

 

[iainhu]

I'm afraid you're on a hiding to nothing without taking it apart. I'm pretty ceratin that the lcd/board contact is the culprit.

No amount of successful startups would persuade me to trust it to work when I needed it. Dark night, GPS bust, take bearings, nip downstairs to plot and, oh arse, it's forgotten them again. You'll be back to writing each bearing down in case it packs up again. In which case you might as well be using an ornery hb compass that needs no batteries!

Oh, I quite agree, only I doubt I'd get as far as getting downstairs! More likely it would pack up while taking the bearings or simply refuse to start at all. This whole episode is a great illustration of what Cunliffe terms; "the volts running out".

At the moment there is no way I could trust to unit to be available when I needed it, but I am doubtful about the PCB contacts otherwise I'd have the thing apart. I thought your experience of breaking your unit open was everything looked fine? Doesn't that suggest breaking the unit apart will buy me nothing but a broken apart unit? However, I also have to subscribe to the view that simply trying retrying the unit isn't buying me much either ;-)

It's a real shame there's no word at all from Raymarine :-(

 

[ianat182]

From your previous postings about this problem it seems that the automatic shutdown switch is cutting in after a period of inactivity,which would be normal procedure when ceasing the work. I don't know how this works; but presumably whilst active it is passing battery power via some kind of capacitor to the functioning module but if the power drops/bleeds off a cutout operates closing down the unit. Could it be that the drain from the battery to a faulty capacitor is the problem.
I'm no electrician,far from it, but even a schematic drawing could provide a clue. Have you tried a PM to Raymarine again?
P.S. How do you switch on the (red?) backlighting to the display?

ianat182

 

[iainhu]

Sadly I think there's more than just the auto shutdown at work as 'locking out' is just one thing, it also likes to display all kinds of nonsense or get stuck on all display segments lit. I think it's a 'logic' problem which probably means a duff component...but why it should just 'go bad' is beyond me.

Re the backlight (white I'm afraid...I suspect it's two grain of wheat bulbs rather than LED) it's activated by pressing the MEM and TIMER buttons simultaneously. I think early units may lack this.

I also found the user manual which can be downloaded from http://www.raymarine.com/submittedfiles/handbooks/instruments/personal_compass.pdf

 

[KenMcCulloch]

It was exactly the prospect of this happening that led me to dispose of mine, which I had had since 1992, 3 or 4 years ago. Someone bought mine on eBay for £80 which I thought was quite a lot to pay for a 15 year old electronic device. A very clever piece of kit but the fixes I plotted with it were no more accurate than using a conventional compass and I don't have to worry about my HB compass failing.

 

[boguing]

I thought your experience of breaking your unit open was everything looked fine? Doesn't that suggest breaking the unit apart will buy me nothing but a broken apart unit?(

Well, I opened mine up because I do this sort of thing a lot, and wanted to see if I could help you. Sure, the pegs broke, but 5 minute epoxy will fix that! Thing is that I knew mine would probably have no water damage, because it is working properly.. Your's isn't!

 

[iainhu]

You broke it apart just for me? That's more than a little generous...makes me feel I must do the same now to justify you 'breaking' yours...and yes I appreciate it can be expoxied back together again.

So thanks for your help...will let you know how I get on

Thx.../Iain

 

[oldharry]

A solution!

Well, I opened mine up because I do this sort of thing a lot, and wanted to see if I could help you. Sure, the pegs broke, but 5 minute epoxy will fix that! Thing is that I knew mine would probably have no water damage, because it is working properly.. Your's isn't!

What a pity! Read my signature.... as I've solved mine WITHOUT smashing it. The problem is the battery contacts, which are not very cleverly designed: The + contact on the unit - thats the one that contacts the side of the CR2025 - can get bent down when replacing the batteries. It then either only makes contact with the lower of the two cells, or shorts the top one out. At 3v supply the display works but the processor doesnt. I am not sure how the contact looked when new, but if it is sticking out clear of the slot it lives in, then the top cell can press it down against the bottom one, causing it to bypass or short the top cell.

Now you spend 2.5 hours as I did, trying to bend the wretched thing back into place so that it makes reliable contact without touching the rim of the lower cell. Its quite solid spring steel, and once bent wont go back, and wont go back, and wont go back, and got it - no, wont go back..... you do have to be a bit brutal with thin nose piers and what not.

Thats fun....

but in the end - RESULT!

At least, I hope so - worked almost perfectly now for half an hour, and some 60 - 70 operations, where it was not working at all before. I say 'almost', because twice it went back to 'silly' mode, but worked properly again after being left 20 seconds or so, so dont quite know whats happening there - yet.

Good luck - its not the easiest repair I ever did!

 

[iainhu]

Have opened case and guess what...?

What a pity! Read my signature.... as I've solved mine WITHOUT smashing it.

Well congratulations and thanks for the news...wish I'd checked for your post before splitting my unit open (with a chisel...which has at least made a neat job of it). I might post some pictures for the benefit of anyone else foolhardy enough to go 'cracking cases')

Well, depending upon your point of view the good news is that the inside of my unit looks pristine...which is as I expected. I've not lifted the PCB as it's partially still held in place by the remains of the welded case pins and I really don't want to crack the PCB just to confirm it looks clean both sides. The bad news though is that I've opened the case only to hear news about a potential fix and of course I've opened the case only to confirm it looks pristine and didn't need opening. But then again, I can now at least check the voltage on the PCB itself and so really know what the unit is getting as opposed to what the batteries give when outside the case.

I had wondered about the +ve terminal shorting and had even experimented with a bit of tape over the inner-most battery in an attempt to ensure the contact couldn't short onto this, but without success.

So now that I have the unit is pieces, what have I learnt? Well first-off, for anyone tempted to do the same, be aware that there are three tiny pressure pins underneath the three face buttons (the red, MEM and TIMER buttons), so remove the back of the unit upwards so that these pressure pins don't drop out of the back of the rubber button and vanish. That warning over...

I can see I have visually perfect battery springs/contacts. I can also see I have 5.5V on the PCB which is what the batteries are giving outside the case. I've not recorded anything as high as 6.6V on my meter even when the batteries were fresh out of their packs. I've also 'adjusted' the +ve battery contact and can see there's no shorting plus I have 5.5V on the board which would seem to confirm the battery contacts are good. So does it now work?

Well it did for a while, much as it has done for short periods while still in one piece, but the 'good behaviour' only lasted a few minutes and then the unit went back to misbehaving. At the moment it's sat with all this display elements lit having switched to this 'mode' after initially starting up with U:UU where the U are the bottom portion of an 8. I've cleaned the batteries and the terminals with meths and warmed the batteries (to coax a little more voltage out of them). After removing and reinserting the batteries and swapping between new sets #3 and #2 I have 5.5V on the PCB and an entirely blank display. The unit is lifeless. I can light the backlight which works fine, but I cannot coax the real gubbins of the unit into life.

So I think in summary I can see what looks a perfectly clean inside and PCB. I can record 5.5V on the PCB which I would presume is adequate and yet have no life or 'misbehaviour', and having had the unit work correctly for about 2 minutes, just as it did while still in one piece, it reverts of 'misbehaving' after a short while. It all makes me think about Ken's comments and the simplicity and reliability of a 'manual' HB compass. It might not remember my bearings for me, but it does at least work reliably every time.