Casio 400V "Select" Button not working (and more)

[Casio Kasem]

Hi, I have a 400V. Love it. The "alternate sound" select button works, and feels spring-loaded, but you have to hold it down. It doesn't "click" into place.

 

I opened this up and desoldered the battery cables, took off the green PCBs and then thought "wow, this looks like a pain." So many soldered connections and I'm not sure those alternate sounds are worth it, but if anyone has any insight on if that switch is repairable or not, that would be great. I couldn't find anything rattling around inside the case.

 

I also notice that the bass notes occasionally have a little "after" noise...like if I roll down the filter and play them, they sometimes have a weird little re-trigger, almost like it sounds like the envelope is retriggering. Anyone else have this? Thanks.

[Chas]

Those push to lock/ push to release switches are a known issue with age. My MT65 and MT68 (both of which the MT400V is based on) have the same problem with the same Tone bank select switch. I've found that if you sort of flick the switch rather than pushing it down, it will sometimes latch that way. There is a moving part inside the switch that might be sticking, or maybe the spring has lost tension.  Either way, I never found a permanent solution and as it will mostly lock when using the flick method I never opened it up to investigate further. 

 

As for the bass notes retriggering, I've not encountered that with mine. 

 

Considering the age of these vintage Casios, a service may well solve most of the issues.

[Casio Kasem]

Thanks Chas. I opened it up and there were so many board-soldered jumpers I just didn't feel like dealing with it for he sake of that one button. I'll try the flick! The weird ribbon connectors gave me particular pause. I have FZ1 display PTSD (those are the worst ribbons I've ever dealt with.)

 

The extra bass notes seem to come and go. It's currently stable. I wonder if it's corrosion or dirt on the key contacts.

[CYBERYOGI =CO=Windler]

You may temporary jam the select button by sticking a thin piece of sheet plastic (e.g. blister packaging) in the gap at the side of it. That's no proper solution but helps to hold it down.