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Display changes

For electronic related stuff like module repair, silver epoxy fixes etc.
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Tuning Fork

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Display changes

Post20 Jan 2017, 14:13

Hello,

my name is Reinhard and I am completely new here. I am collecting Titus watches and there are a few lcd models. With one aof them I have got a problem.
When the watch isnt worn, it works. when its on my hand the display changes. I have heard that this is through my body heat. Down this post you can see on the first picture the watch after putting a new batterie in it. And on the second after wearing it for half an hour.

Now can you tell me what I can do? Can I, someone repair this watch?

Thanks for your comments and ideas.
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767Geoff

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Re: Display changes

Post20 Jan 2017, 20:07

Welcome,

Photos, photos photos, and did I say photos. Just with your phone if need be. Do you know how to remove the modules? What level are your DIY skills? Do you have tools? Sort of like trying in to diagnose as a doctor, over the phone, with a patient with an unknown knoledge base. But here goes:

Remove the module, inspecting for battery corrosion or any obvious faults. If packed with contamination then diassassemble, clean mechanically or with a dilute vinegar solution (search website for description). after rinse and dry reassemble. If now contamination proceed to 1) below but read entire post first.

Still faulty?

Then apply some DeOxit electronic cleaner with a watch oiler to mechanical connections

Still faulty?

Then proceed to 1 below

Heat expands and lack of heat contracts metals and plastics respectively.

The display problem is obviously a result of this. In electronics the term is 'creep'. ICs on a computer board that are plugged into sockets can expand out of their sockets when heated but do not reset into their sockets when cooled. Thus they creep out until a leg/pin no longer contacts the socket and the computer exhibits a fault depending on the IC.

1). In your watch the LCD panel is compressed onto zebra strips which conduct the signal from the PCA to the LCD panel. The compressor is usually a metal frame held in by clips or screws depending on the design. This MAY be the fault, the compressor frame may be creeping upwards when warmed, relieving pressure and breaking thue contract for the signal at the one point affecting the first LCD segment.

With this problem, remove the watch module with battery installed. Does the watch still display or is the case part of the circuit? If the watch displays and is warm enough to exhibit the fault, gently press down on the LCD compressor frame at the display with the segment fault. Did it correct the fault. Then you know the frame has crept and needs to be tightened (screws) or bent in the direction that causes it to exhibit more compression. If the case is part of the circuit it is necessary to remove the watch and with a wire clip, complete the case circuit by bridging the case to module contacts and test by pressing as described.

2). As described above but the creep is affecting the IC which contain the display driver chip or some other component causing a contact to break affecting the display. MUCH MORE DIFFICULT especially if the ICs are encapsulated in epoxy. Unfortunately it appears that this is the problem, it appears to be a fault with the display driver. When heated it is sending extra signals to the display.

I would test exposed traces with a continuity tester (multimeter) when the watch is cold and then heat it with a hairdryer (not hot just warm) and recheck the circuit for continuity to isolate the component which has crept under heat from its solder or conductive glue joint. If the fault isolated then remelt the solder joint or apply more sliver conducive epoxy.

Conclusion:

-One must start with a clean module. Either it is clean or you must clean it.

-check the easy stuff first; faulty mechanical contacts

-check hard stuff second; faulty. Solder joints, glue joints (continuity check)

-determine the worst, damaged or faulty ICs.

Cheers, Geoff

Example:

Just picked up a pristine NOS 0757-4020 Bond dial Seiko. All original, no scratches, perfect strap. No alarm function though hence the lower bid price of $80 USd. Came with original box, tags and manual. Opened it up, removed module expecting the alarm contact spring to be missing. Oops, it was there. Got another. Alarm case back and tested the module on it, intermittent sound. Ahhhh, the circuit wants to work. That is when I noticed the battery clamp. Was missing a screw and allowing the watch to run but one end of the clamp contacted the case back. Screwed it in place with a spare screw and now the watch works perfectly. Lucky me.

My understanding of the Titus brand is that it is heavily marketed in Asia and less so in America and Europe. Stores are full of Titus in Hong Kong but not here in Canada.

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