Datatime LED watch

[Pauly]

Hello everyone. Ive just picked up an Datatime led watch which had corroded batteries inside. Ive cleaned it up but it is only displaying a 0 in the last column. This is on constantly even without pressing either of the two buttons. Have checked for short circuits on the board and it seems fine with all wire bonds intact. Any help would be much appreciated. Cheers guys.

[bucko170]

One constant digit is usually a good indication that the quartz crystal has completely failed, although it does not rule out the watch having other faults swapping the QC would be worth a try.
New 32.768 KHz are inexpensive and easy to find, you would need to check the module because if the module is a Hughes you would need a donor QC from an old module as they used a different frequency (786,432 KHz) which is no longer available.
Good luck.

[Pauly]

Hi Bucko 170 and thanks for your quick reply. Excuse my ignorance but am not sure what module it is. It is just printed with Made in Hong Kong for Datatime Corpuration on the casing. The crystal has M 127 on one side with MTQ32C on the other. Hope this makes some sense to you and any ideas where I might get a replacement?

[bucko170]

Hi Bucko 170 and thanks for your quick reply. Excuse my ignorance but am not sure what module it is. It is just printed with Made in Hong Kong for Datatime Corpuration on the casing. The crystal has M 127 on one side with MTQ32C on the other. Hope this makes some sense to you and any ideas where I might get a replacement?

A photograph would make it easier to identify although the 'MTQ32C' stamp does suggest a 32.768 KHz QC.
I would try a QC change first before looking for a replacement module.

[Pauly]

Thanks for that. Am going to try to attatch a picture of the module and I hope its better than my last attempt. Apologies in advance if it doesnt work or is poor quality

[bucko170]

Sorry but I am not sure what make that module is hopefully others will be able to identify it for you, maybe it's a Hantronix?
The QC will be on the reverse side of the board.
For a spare module you could try Ed 'retroleds', he might even be able to repair it for you, for those that do repairs a QC change is a relatively easy task, if you decide to purchase a spare module you would need to include a photo of the module, the size (depth & diameter) and the button lay out so he can match it up.

[Pauly]

Thanks for that Bucko. Have posted a picture of the reverse side of the module still in its casing along with the crystal that I purchased from Maplins yesterday. Looks like a simple job but will have to dig out my old low wattage soldering iron as my usual 25W will probably be a bit too hot. Will post pics of my progress. Thanks for the info on Ed of Retroleds. May ask him about the Litronix from my old trafalgar as thats the sentimental one that I really want working

[bucko170]

You should be able to remove the black plastic casing from around the board to make the soldering a little easier.
There are one or two tips on the forum relating to replacing the QC, a couple that I can recall - be careful when bending the wires at the bottom of the QC, the aim is to bend just the wires without disturbing the seal were the wires enter the body of the QC and it is important to use a heat sink to avoid heat damage.
I think I am also correct in saying a new QC has a bedding in period and might be slightly off time wise for a period of time after installation.
I have managed to successfully change a few QC's myself and I am pants with a soldering iron, so it's not that difficult.

[Pauly]

Yes I removed it from the case quite easily. Will try and do it over the next few days with step by step pictures. As you say, the heat sink will be important so fingers crossed.

[Pauly]

Hi guys. Just a quick update on the above. Finally got a bit of time to change the crystal, powered it up and it still shows the same single 0 digit. I can only assume that the IC is shot so will put this one to rest now. I hope the next repair will be a bit more succussful but will start that one as a new topic.