Quick SBC 251PLUS - battery type selector

[Ziffius]

On my quick mains charger is a tiny sliding switch to select either gel or wet cell batteries. Unfortunately when I went to change from gel to wet having replaced my agm’s for sealed batteries the top of the switch pings off. I hunted high and low in the area but couldn’t find it but did find a tiny gold button/disc about 1.5mm in diameter. Looting at the base of the switch I can see what looks like a row of gold buttons with the middle much lower. So now I am not sure what type of battery the charger is set for.
I dismantled the cover of the charger and found the top of the sliding switch (the slider) inside but putting it back onto the switch doesn’t feel right. The gold button doesn’t want to fit in the middle of the switch and appears too big. So not sure if it came from here or not.

Anyone have any clues about this switch and it’s workings?

[Lyra]

Could not understand the details.
Upload a picture of the switch area, I think it will make things clearer and better understood  to try to help you.

[Ziffius]

Wish I had thought to do that whilst I had it all in bits. At sea at many Kent but will get a pic of the switch when I’m at anchor in meantime I have photo of gold button thing I’ll put a scale on it later

[Lyra]

When you write " a row of buttons" - is it 3 buttons (or actually 3 contact points)?
And if so - is the button in the photo large enough to simultaneously touch the middle contact and either of the contacts to its side?

If both the above are positive then maybe it goes like this:
The button in the picture is a contact point held under the switch plastic cover, probably with some sort of spring. Sliding the switch it makes contact between the center point and either of the other two points.
If you know which way to slide the switch for each of the battery types then it is a matter of making electric contact between the center point and the correct point. I have no idea how the charger behaves if both contacts are open (as it seems to be your case right now).

My boat also has a Quick SBC charger (not sure which model), I will be there today and if  if I get a chance (it is buried below the nav table) I will take a look and see if it has a similar switch.

[Ziffius]

The switch is recessed such that is finger proof- only way to move selector is with a small screwdriver and that’s what’s caused the problem. The amount of slide is very small and it was hard to see if the switch had changed position.
The three gold contacts - the outer ones are high and the middle one deeply recessed such that the sliding part of the switch can’t make contact with it unless there was something else in there. The spare gold disc is slightly too large to drop down on it. I couldn’t find any springs anywhere but they tend to fly when they pop out. The housing is now damaged so the red slider won’t stay in even if I found the right bits and figured out how to fit them.
Not on shore power at moment so can’t be sure what the current setting has defaulted to but looking at the charge voltage before I left I suspect it is in the GEL position ie higher voltage.

Looking at the metal strip under the red slider I can’t figure out how the contact sequence would work. It would be possible to bridge the contacts underneath the circuit board. I checked the resistances and the contact nearest the charger housing seems to be isolated from the middle contact whereas the contact furthest away seems to have a resistance to the middle contact if about 140kohms but I will have to dismantle it all to check fully. I might be able to get on shore power tomorrow.

[Lyra]

What I see makes me believe that what I wrote before is correct - the center contact makes contact to either of the side contacts.
 As to the disk being too large, maybe it was the opposite - a spring touched the recessed middle contact and the disk was riding on top of it. Or as you already wrote, maybe it simply does not belong there.

Anyhow, at the moment I would try to find a way to bridge the center contact with the correct side contact, maybe just solder a short piece of wire.

[Ziffius]

Lyra you are probably right I’ll have to jury rig a connection to test what it does when mains power is applied - it’s just in such an awkward place. I noticed the new chargers from quick have much easier selector