750c Display Documentation

[ykick]

Measuring 1.1V on a battery cell which should be around 3.3V is a battery issue.

All FW becomes totally unpredictable if circuit voltages fluctuate at or below minimums. Dying empty battery will sag and recover slightly as the load is removed. Rinse and repeat that a few times and who knows what the clock displays.

[SM300]

This isn't a battery issue as much as a firmware one. My battery is never disconnected, I only shut off the display. The time remains correct for up to an hour if shut off and back on. Beyond that the time "freezes" and then begins at that time when powered back up... or in other cases it loses time during that period but is still running. If the battery failed, the time would reset to factory defaults. It's remembering time, but just not accurately. To me this is clearly firmware at fault.

[squirrelpie0]

Anyone hear if and how there is going to be a firmware update for the 750C?

[MichaelT]

RTC battery does NOT take a charge, it runs down then you replace it.
Have you never replaced the RTC (Real Time Clock)/CMOS battery in your PC?

[Lost]

Sounds like maybe we need an LIR2032? https://www.tindie.com/products/bobr...arger-lir2032/

[ykick]

Or perhaps the question - "is there any charging current" designed into the circuit?

I wish my 750C worked, I would try to find out...

[Lost]

^^^Thanks for that! The question no becomes if the (TINY!) charging current will screw up that battery. I would doubt it.

Link to a battery. http://www.jameco.com/z/CR2032-LEADS...gaAt8fEALw_wcB

[MichaelT]

3V, 5.5mAh, 0.27" Dia x 0.08" H (6.8mm x 2.1mm).
https://www.digikey.com/product-deta...057-ND/1889208





Try something with a MUCH larger capacity......
RTC (Real Time Clock)/CMOS (Complementary Metal-Oxide-Semiconductor).....bios memory.

[ykick]

When the unit was opened, did anyone check the battery voltage? I wonder if the battery is actually dead or a design flaw.

I have a recently dead 750C laying around. Opened it up and checked out the MS621FE button battery. It’s supposed to be 3V lithium rechargeable but only measuring 1.1V.

Picture speaks 1000 words -


Since the display is dead to me I’m not sure if this battery is supposed to have any charge applied as installed in the 750C when connected to a battery pack?

[Lost]

Hoping to see a resolution to this soon. I use a Shark pack on my BBSHD and remove it when I get to work each day. On my ebike with the DPC-14, this hasn't been a problem, but I hate having to reset the time on the 750c every afternoon when I ride that ebike.

I wouldn't let that rent too much space, I have a watch and a cell phone. It's just an annoying "feature" that if anything. highlights a lack of beta testing. I like the display overall, it looks more integrated on my bike, not like a stuck on afterthought. For that, I'll give it a pass. BUT: If I knew for sure that it was a defective battery, I'll work on replacing it.

[mtrain13]

Did you happen to note the voltage on the battery? Thinking of adding a replaceable CMOS battery and disconnecting the original battery.

[mtrain13]

Hoping to see a resolution to this soon. I use a Shark pack on my BBSHD and remove it when I get to work each day. On my ebike with the DPC-14, this hasn't been a problem, but I hate having to reset the time on the 750c every afternoon when I ride that ebike.

[Lost]

When the unit was opened, did anyone check the battery voltage? I wonder if the battery is actually dead or a design flaw.

[skymon]

For the record, I still use the 750c even though its buggy. I prefer its mounting and low profile enough to put up with the bugs.

[ykick]

My 1st job out of college was working for GI (General Instruments) Jerrold division cable box depot which opened a new production rework line for replacing defective button batteries on PCBs. Large number of new cable boxes were found to have defective Sanyo button batteries and the “settlement” reached was that Sanyo financed the creation of the rework line and 2 shifts working to fix the engineering recall.

It was not a bad gig and they kept me on as a bench tech once the project was completed.

Oddly there's no soldering to PCB here? That sounds like a problem waiting to happen....