14 Dec 2011, 21:00
Hi,
I recall a while ago reading a thread on this module with some theories (I think from Rewolf) about the elastomer pusher contact shrouds and chassis plate spacers in this module. I tried searching for the original post but couldn't find it. I couldn't remember any definitive conclusion to the discussion, apologies if that was just me not 'turning the page'
Anyhow, my growing thirst for simple old LCD modules in big lumps of steel brought me a 64100 last night and I had it in bits to fix. Only took quick photos as there was another acquisition that was calling me
-
The three pusher contact shrouds (seen resting just north of the circuit block) are indeed conductive at DC - low 10's of ohms depending on pressure and Surface Area of contact. They presumably provide some environmental protection, some 'feel', some debouncing, some conducted EMC protection and provide plenty clean enough voltage into a high impedance IC input.
The pusher on the right of the picture doesn't have a shroud as it is for the backlight, is unbuffered and so must switch supply at low dc impedance.
The elastomer spacers on the chassis also measure as conductive with low 10's of ohms dc impedance. They contact on the obvious pads on the top of the circuit board. An additional benefit to these is that they hold the brittle ceramic PCB firm between the front and rear metal chassis plates without nasty stresses. They will also provide some shock protection in use.
As appears to be the concesus, the whole thing is really well made. Face on this one is green Orient-style. Case is a hefty 40mm (W) x 42mm (H). Model number is TS641102-40.
Last point of note on this 64100 module is that it is designed for thin AG3 type cells. One side of the gold battery cover has a longer bent spring contact and there is a brass 'pill' for the other side. Kind of odd way of doing it? I did note from looking at photos on DWL that a module marked 64100A did not have this 'feature' and was presumably designed instead for AG5 type cells. Ditto the 64101 photos on DWL - contacts for 2 x AG5 types.
Rgds,
MP.
I recall a while ago reading a thread on this module with some theories (I think from Rewolf) about the elastomer pusher contact shrouds and chassis plate spacers in this module. I tried searching for the original post but couldn't find it. I couldn't remember any definitive conclusion to the discussion, apologies if that was just me not 'turning the page'
Anyhow, my growing thirst for simple old LCD modules in big lumps of steel brought me a 64100 last night and I had it in bits to fix. Only took quick photos as there was another acquisition that was calling me
-
The three pusher contact shrouds (seen resting just north of the circuit block) are indeed conductive at DC - low 10's of ohms depending on pressure and Surface Area of contact. They presumably provide some environmental protection, some 'feel', some debouncing, some conducted EMC protection and provide plenty clean enough voltage into a high impedance IC input.
The pusher on the right of the picture doesn't have a shroud as it is for the backlight, is unbuffered and so must switch supply at low dc impedance.
The elastomer spacers on the chassis also measure as conductive with low 10's of ohms dc impedance. They contact on the obvious pads on the top of the circuit board. An additional benefit to these is that they hold the brittle ceramic PCB firm between the front and rear metal chassis plates without nasty stresses. They will also provide some shock protection in use.
As appears to be the concesus, the whole thing is really well made. Face on this one is green Orient-style. Case is a hefty 40mm (W) x 42mm (H). Model number is TS641102-40.
Last point of note on this 64100 module is that it is designed for thin AG3 type cells. One side of the gold battery cover has a longer bent spring contact and there is a brass 'pill' for the other side. Kind of odd way of doing it? I did note from looking at photos on DWL that a module marked 64100A did not have this 'feature' and was presumably designed instead for AG5 type cells. Ditto the 64101 photos on DWL - contacts for 2 x AG5 types.
Rgds,
MP.