Any quartz clock experts?

[PaulMB]

Just bought an old Braun quartz alarm clock in a flea market, 1 Euro. The battery inside, a fairly chunky thing, the length of an AA but fatter, marked 1.5 volts, was all disgusting and covered with white crystals/poweder. I've temporarily put in an old AA, which jams in. The clock runs, but erratically loses a couple of minutes every hour.

First question: can an old battery make a quartz clock run slow? Or maybe it is missing a beat every now and then?

Second question: Inside the clock there is what looks like a copper disk, maybe 2cm in diameter on about 3 cm. of wire. It looks like it should simply sit along the inside of the case, apparently not connected to anything except the wire which disappears into the works of the clock. What is this disk for?

The clock is a Braun "Silentime Quartz" model 4838/AB20sl

Grateful for any ideas.

 

[PaulMB]

Just found a photo of this clock with the back open: the metal disc seems to be jammed in against the inside of the casing and held there with a metal spring "clip" fastened to the circuit board. My "clip" is absent, and without taking the thing apart, which I fear greatly, I can't tell if the "clip" was connected to anything in the circuit.

(I will fully understand if the great minds present on PFM have better things to do than waste their time on an idiot who buys 1 Euro used alarm clocks)

 

[Rowan]

Have you tried turning it off and turning it on again?

 

[Paul R]

Is the battery likely to be a 'C' cell?

Can you link to photos?

Paul

 

[PaulMB]

Yes, I've turned it off and on several times (there is a start-stop switch when you remove the back cover).

Yes, the battery is indeed a "C". I've just put a new one in now and set it against my computer clock. Will report back if it is now accurate.

I have noticed that the alarm does not go off. And there is still the mystery of the metal disc.

 

[sq225917]

Think your copper disk might be a piezo of some kind that should be affixed to the case so it can use it as a sound board?

 

[PaulMB]

Think your copper disk might be a piezo of some kind that should be affixed to the case so it can use it as a sound board?

Not sure what that means, so I think I'll take it to a clock repairer, who will doubtless tell me to throw it away and buy a brand new 10 Euro clock.

In the meantime I've found that even with a new battery and cleaned contacts, it loses about 30 seconds every hour. I thought quartz mechanisms were perfect.....

Thanks everyone!

 

[vuk]

paul.

can you show us a picture of the clock?


vuk.

 

[garyi]

The pizo is like a tiny speaker, so sq may have nailed it if you dont hear the alarm.

 

[Minstrel SE]

Chuck it away and buy a 10 euro radio controlled clock or something. You can put it down to people handing junk into charity shops again. Sorry

Honestly these things either work properly or they dont when you put a battery in. Its not worth your time and effort.

I have noticed that the clock function on some of my cheaper little gadgets ( Quartz travel clocks, weather station, FM clock radio) are rubbish often losing/gaining minutes over a month. Even the ones on full size tuner separates can be poor in terms of accuracy when not updated by RDS

I went radio controlled and never looked back.

 

[matthewr]

Some of them are quite funky. I like this one:

Although I think Paul's might be one of these:

 

[PaulMB]

Yes! Mine is the one in the bottom photograph. I'm sorry but I still haven't learned how to post pictures, so I'm very grateful to Mathew.

And since I know that PFM en masse is waiting for news with bated breath, I can announce that it has now, after two days, inexplicably started running accurately.

As for the alarm, I opened it and discovered that the metal spring clip that should be pressing the metal disc against the inside of the case but is missing, was originally soldered to a connection on the PCB.

So the piezo theory sounds reasonable, and at some point I will endeavour to re-manufacture and solder in a spring clip. Phew!

 

[hc25036]

I had one of those years ago. Survived two business trips, then failed to go off and made me late for a meeting!

 

[TPA]

I fear the worst, you may be in for another Euro and a complete replacement.

 

[PaulMB]

Indeed! Serious talk with bank manager tomorrow.

But seriously, the thing that makes me furious is that if you try and buy a new alarm clock these days there is nothing as simply perfect, well-designed and functional. Its all cheap gimmicks and Chinese-baroque styling.

 

[stevec67]

Really? They are all over markets in the UK and Poundland. 5cm x 5cm x 3cm deep, plastic box, any colour, white face. Simple, effective and disposable.