Arctos Stem Set LCD

[quietman]

Hallo,

I know theres some very knowledgable vinatge LCD enthusiasts from continental Europe who frequent the forum so I thought I'd ask about a big old Arctos I picked up a while ago ......





The back cover says "All Steel Water Resistant Discu-safe" but I think this is pretty generic for Arctos as I think they also used this basic case for analogue watches back then. The serial number is 25627 if that means anything. The movement is 31mm diameter with an FR PCB taking 2 x SR43 cells.

I have read that there were three Arctos LCD movement types. The 575 came in DSM and FE variants and had time display only. The 675 and 775 came in FE only and have date and seconds display as well - as does my example - pushing the crown in once brings up the date and twice brings up the seconds display.

So I think its either 675 (manufactured 1975 to 1977) or 775 (manufactured 1977 to 19??). Anyone know these watches well enough to offer any more info or date/ID it more specifically

MP.

[azimuth_pl]

hi there,
I'd say this Arctos is from 1975 latest as the crown would be rather obsolete by then.
I have been searching for this watch many times but always found them to late.
Most of these sold for very low money so I was not happy either.
Can you gut the module to show the construction?
Probably similar to that of Seiko stem-set watches.

Piotr

[quietman]

Oh, I made a mistake in my previous post - actually you pull the crown one position to adjust hours and to the second position to adjust minutes (or 1st position AM/PM and 2nd position date if you press onto that display before pulling the crown....) There is no up/down which kind of makes it a fake crown! (Been playing with too many Japanese watches recently )

I didn't take pics of the insides and the watch is kind of inaccessible right now.... There's no 'proper' keyless works but rather the crown moves a slider that carries a set of three gold contacts that selectively bridge various pads on the PCB according to the crowns position. I spent ages poking and proding trying to release the crown so I could get the movement out but in fact you disassemble by removing the back plastic chassis piece by unclipping around its perimeter. And then everything else drops out from there.

There's not much on the back side of the PCB but tracking / Xtal / Trim Cap and a few other discretes. Everything else is on the other side under the LC panel which is held under a pressed metal frame. I didn't pull all of that apart as I have a worker and didn't see any reason to accidentally mash wirebonds or crack the LC panel. Overall I'd say the movement design was clean and efficient but unspectacular. Thats perhaps in part due to the two battery architecture which eliminates some of the PSU circuitry that clutters the back-side of many early Japanese watches. With no backlight, buzzer, keyless or buttons its all in the silicon and glass.