Heuer Chronostop Manhatten LCD Module Dead

[tycooke]

I just purchased an Heuer Chronostop Manhatten from 1975. The analog movement works okay but the LCD module is dead. No bleed throughon display face. All connections and contacts have been checked. Had a hard time removing back as screws were rusted and some screw heads broke off. Not sure if water got at lcd movement. Any help troubleshooting this module appreciated as this is a watch worth collecting I have heard.

Thanks,
T.Cooke

[Old Tom]

Hi, the Manhattan is very sort after! However the digital modules are notoriously unreliable. Usually it is the panel that causes the problems- they seem to have been badly made and the nematic material reverts to the liquid state (the display goes black). In your case it looks like the display is OK so problem lies in the electronics or all the various PCB contacts. I don't know if you have dismantled the module yet (take the battery spring clip off completely and then you pop off the two display retaining latches on the bottom of the circuit board and carefully lift off the clip & display. If you do this you expose the totally unprotected (no protective gel or whatever) circuit chip and connecting wires. Inspect carefully to see if any of these fine wires have broken away or collected any corrosion debris (white or green crystals). Broken wires are beyond the skills of most people although I can think of one or two who do do rebonding work. If you have corrosion crystals on the wires resist the temptation to poke at them, try and puff them off with a watch blower (not a compressed lens cleaner type, too vicious). Also worth inspecting the zebra connector between the circuit board and LCD for specks- a single speck on the common connection stops the whole display working. Getting at the crystal in this module is not easy because of the clear plastic mounting frame which is difficult to remove without breaking it or some of the wire bonds. Apart from the above there is not a lot more you can easily do with this module but even not working completely the watch commands a decent price- good maker & an attractive shape. One last thing- in quite a lot of LCD watches I have noticed you get an almost colourless coating of corrosion on the negative terminal which is non conducting- doesn't always come off with the usual fibreglass brush/fine emery stick type of cleaner and is the one case where a light application of a sewing machine needle to scratch the coating off is acceptable.

[tycooke]

Thanks for all your info. The circuit chip under module has come unglued and is loose. Was it originally just glued in place or mounted with some other adhesive? Any place on Internet to get a schematic of this module? If you want I can post picts of the module. How can I test the display with test leads and a battery? Again,thanks for your help.

T.Cooke