Digital clock gone haywire!

[Birotor]

1991 16TGS Estate: Digital dashboard clock gone haywire! On starting up goes to 1 pm runs to 2 some thing pm and goes back to 1 pm of its own accord! I wonder if it is worth saving or is going to be useless not just replacing it?

[Tim Leech]

I would replace it Ioin.

[Vanny]

What happens if you press on the casing? the screen is wired to the circuit board through what i can only describe as conducting rubber. I think there are around 32 connections in total. If the rubber gets dirty or mis aligned (ie if the clock gets dropped), then you can get some funny results!

I'd suggest you take it apart (you have nothing to loose) take the pink rubber bits out, clean the edges, and put it back together. Chances are it will start working normally!

Oh, while your in there, you could change the back light colour. There is a little slip of coloured plastic which you can change, personally i replace it with a piece of shopping bag. My clock matches my stereo colour. Sad, i know, but better than green!


I certainly wouldn't just jump to replacing it without having a good old play first, i might have spares, but i'm not going to throw good money away.

[Birotor]

Right something to do over the long week end! It sounds as a friend at Cammel Laird would have said "Worth a coat of looking over!" Thanks for the tip. Eoinsloan aka Birotor.

[docchevron]

what vanny said, it's a bog standard clock LCD setup, and nearly always cured by giving it all a good clean and reassmebly carefully.
I like the orange effect myself...

[Birotor]

Never got beyond lifting the tray! Wonder why Citroen used Torx 20 headed screws to secure it - blatant attempt to deter DIY I suspect! Any way when I had got the car the car the intention was that the vendor would fix three minor issues. When the chance came for him to drop it off at my place and go off in my C1 which was part of the deal, I said I would deal with them. As an experienced Marine Engineer Officer in diesel and nuclear submarines and several frigates I was confident! Coming into it in the middle so to speak I failed to see the full picture! The clue was to see if the defects were connected! Well of course they were! I hadnt had a BX for 22 years... The three things: Clock, Interior lights and central locking... got it... ALL ON THE SAME SAME 30 amp fuse! Cause of blown fuse a boot light that had been broken some time in the past when changing a lamp and caused a short circuit. None of the other circuits on that fuse were ones that affected me (Cig lighter - dont smoke, radio - car came with a replacement head unit with CD and MP3 input for me to fit, etc). Replace one 30 amp fuse and the boot light and all three issues were of course fixed. All major fuses will now be fitted with diode fuses which light up if they blow - a trick I first used in my 1969 Porsche 911/TR which I stage rallied in Germany. Question: With the fuse blown where was the power coming from for the clock operating as detailed in my original post?

[citronut]

in the ealy days of new BX's there was a tech'y bulletin from citroen on erratic tic tic tic tic digital clocks,
if memory serves it was on cars with the LED rev counters,
we had to fit a component in the rev counter feed under the bonnet at the N/S/R corner of the engione bay,

the component turned out to be exactly the same as a GS points ignition condenser,

someone probably has a copy of the bulletin,

the clock would gain or loose time at random before the mod as the pulse from the rev counter feed was interfering with it

regards malcolm

[electrokid]

Question: With the fuse blown where was the power coming from for the clock operating as detailed in my original post?

The clock has a permanent supply (presumably the one through the fuse) and also a supply from the ignition cct to bright-up the display by running the bulb, and another from the lighting cct to dim the bulb at night. My guess is that one of these other supplies might have made it look as though the clock was running.

Oh, while your in there, you could change the back light colour. There is a little slip of coloured plastic which you can change, personally i replace it with a piece of shopping bag. My clock matches my stereo colour. Sad, i know, but better than green!

I'm happy with the green - but I keep a bunch of different theatre gels so maybe time to experiment !

[Defender110]

Never got beyond lifting the tray! Wonder why Citroën used Torx 20 headed screws to secure it - blatant attempt to deter DIY I suspect!

Torx scres are apparently normaly used when machines or robots are being used for manufacture as they are more easily held and centred.

[mat_fenwick]

Interesting (or otherwise!) fact: Phillips screws were designed for the bit to slip, to prevent overtightening when tightened by machine. Now it's possible to have much finer torque control than in the early days so manufacturers are free to choose screw head designs that are resistant to slip. If they really wanted to be awkward they could have picked something like a Bristol head!

[docchevron]

oi! It's well known that Bristol heads are the choice of champions!

[mat_fenwick]

I had a feeling you might know what I meant!

[docchevron]

You cant spend 32 years here and not! Both varieties!

[mds141]

oi! It's well known that Bristol heads are the choice of champions!

Please enlighten me!

[Birotor]

I reckon electrokid has hit the nail on the head! There are connections to the lighting circuit and a maintained supply not switched by the ignition key. I found them in the current flow diagram in Haynes and Revue Technique which just show these supplies into the representation of a digital clock. A bit like the memory supply to a car radio.... Many thanks....