Topic: Interior view HP2551-C

[krojan]

I unscrewed a few screws and this is the view.
I am interested in what the SW8 switch is for.

[galfert]

This SW8 is present on the Ambient WS-2000 also. I would never have known since I haven't opened mine. There is a little hole in the back of the case to access this button. But it is not labeled. A few months ago I read the entire manual and I don't remember it being mentioned. I decided to press it momentarily with a paper clip and noticed no effect. You can feel and hear it click. Maybe it did something and I haven't yet noticed what. I pressed it while the power was on.

SW1 at the bottom is the Reset button and that is clearly labeled on the case. Interestingly this button is at a different angle than SW8 you found.

This display is not a new design. This same looking display was used for the WS-1000 (but it was silver instead of black). I don't know if the button had a function in that previous model. It is possible that it is a carry over that is not needed anymore. But the question then is why waste the component on the PCB if it isn't used? Often when a PCB is used in different models you see that components are just not present but the PCB traces pads/holes and labels are present but there is no component. It could be there for some future use waiting to be unlocked by a future firmware.

[galfert]

I've been thinking about this and after looking at the PCB line traces I think it has to do with the RTC (real time clock.) So I think it is a reset for the RTC if it gets all funky or frozen. Instead of needing to open up the case and remove the battery, all you need to do is press the SW8 button. You probably need to push it for a few seconds to discharge any capacitors and you probably need to do it while the power plug is removed.

That is my best guess.

[krojan]

I wrote to Lucy in this matter and I received an answer like that:
"The place you indicated on the attached photos of HP2551-C console is for inside testing usage and not available functions for users."