Last year for Yashica Data-Backs...

It was probably more a matter of trying to figure out how long it would be before introducing the next models, and how long afterwards people would switch over to the newer stuff. Of course, that became a mute subject when Yashica folded.

PF

My question then … so why didn't they?

I was just about to pull the trigger on a 137 DataBack at KEH. I guess I should hold off until I can find out if it's also effected by the 'expired' chip. I should also go through the ones I already have to figure out whether any others are doomed as well.

Thanks for the reminder biggles3

I dug up a dealer sheet on the 137 back, and it turns out it's the D-5. That one won't do intervalometer functions, so that leaves only the index, count, and 2 types of date/time stamps. Without doing intervals puts a limit on its usefulness for me, so... out of the basket it goes. I still have to look through the others, and assuming I still have batteries, I'll post details, once tested.

To fill in the blanks on the Dental Eyes - I have the I and III. I don't have the optional back for the I, but I don't recall it having more than just date functions from anything I've read, but I don't know what date-chip it uses for setting the current year. I think they only came with dial-type settings knobs, and not the later push-button panels. With the body based of the FX series, I doubt it would have intervals anyway, and it might be an early type that can't handle current dates/times. The III only has date functions in it's 'Date-Unit' (as the manual calls it), which won't do intervals. According to the manual for the Dental Eye II, it too uses only dates. It looks to be the same back as on the III, and both were included with the setup, and not optional backs like the I. I presume that Dentists created far too many photos over time, and wouldn't want a tool unless it had a date function as a default.

My RX I's have the correct dates, but sadly no interval function. It looks like they use the same 'Date-Unit' that's on the Dental Eye III - which also shows today's date. I have one data back for my 167's to swap back & forth that does have the interval functions, and it is indeed a D-7. I'll have to dig out the 2 button cells to power it up, but it was working correctly earlier this year. Why on earth they stuck them under a panel only accessible when the film door is open, is beyond me though.

Thanks for the thorough rundown on the capabilities @biggles. I thought I had a back for an RTS I, but if I do it's run off to hide somewhere, but otherwise, what I do have is working okay. Luckily there are still batteries, and they're cheap too, so no reason not to use them if you need the functions.

EDIT: After looking at the details shown in the Dental Eye II manual, the backs are not the same. The II also uses a CR2025, but like the D-7 back, you need to access its battery compartment by opening the back and unscrewing a cover plate from the inside.