Maker Pro
Maker Pro

Please help me Identify this part, thanks!

george2525

Jan 30, 2015
170
Joined
Jan 30, 2015
Messages
170
Hello,

I have a Casio Celvanio Keyboard and the Volume knob stopped working. It just stays the same level if I turn it.

I managed with some work to access what I was hoping would be a typical potentiometer but sadly I found this....

It Has 5 pins (there are 3 more under the 2 visible in the picture) and is annoyingly mounted to a small PCB

I would love to try and replace the part but Ive not had experience with 5 pins before and I cant identify the part name.

I would be eternally grateful for any help, best wishes

Screenshot_2021-09-07_18-49-36.png Screenshot_2021-09-07_18-49-58.png Screenshot_2021-09-07_18-50-14.png
 

george2525

Jan 30, 2015
170
Joined
Jan 30, 2015
Messages
170
Its a casio celvanio AP500
its a digital piano, maybe not classed as a "synth"
 

bertus

Moderator
Nov 8, 2019
2,792
Joined
Nov 8, 2019
Messages
2,792
Hello,

As I said, the schematic came from the AP200.
I assume a similar part is used in your system.
As you can see in the schematic, the ground connections are common for left and right.
The VR601 is only a location on the PCB.

Bertus
 

george2525

Jan 30, 2015
170
Joined
Jan 30, 2015
Messages
170
ok thanks. That service manual is interesting and not entirely useless

Could I please ask this: In the photo you can see the 2 largest blobs of solder which seem to function purely to hold the component into the PCB (I think!). Yet the left (in picture) of these blobs or "legs" touches a track of the PCB. I have little experience with PCBs so wondered if this is a connection and if it has any significance?

hope that made sense. Thanks
 

bertus

Moderator
Nov 8, 2019
2,792
Joined
Nov 8, 2019
Messages
2,792
Hello,

The large blobls are for holding the part.
You are right about one of them being connected to a track.
It is for shielding, as the holder is made of metal that can be seen as a shield for noise.

Bertus
 

73's de Edd

Aug 21, 2015
3,463
Joined
Aug 21, 2015
Messages
3,463
Sir george2525 . . . . .

Indeed that is your units dual section volume control.
Take note that the two LARGEST solder connections that you refer to are connected together on top side by being manufactured as a common metal stamping.
Then both connections end up as AUDIO GROUND connections at the connectors / plug ins..
I think that you are having NO problem with this unit.
CONFIRM THIS . . . . .:
You perceive the volume control as NOT working . . . . . but now reveal / answer this . . . . .
You surely must have an incoming or self generated sound source that you are basing this available audio level discrepancy upon .
Lets say that your sound NOW being heard is so LOW that it is ONLY 5-10% of past times max level of volume.
S o o o o o o o . . . . . if you are now turning that vol control to its max CW position and EXPECTING that 100% prior level of sound, but you are only getting ~5% max.
You then are perceiving a malfunction of . . . . . . da volume control IS NOT woiking ! ! ! !
But now you need to listen . . .bewy . . .bewy . . .cawefuwwy . . .( A la Elmer Fudd).
AS you rotate that volume control backwards (CCW) to get a lower volume level of that now only available 5% level . . . . . will it gradually diminish that weak audio level, on down to a ZERO speakers / headphones volume output at the volume controls FULL CCW position ?

If so, you have actually experienced a failure of the units audio level PRIOR to its reaching that volume control . . . since your volume control IS being able to control that available mere 5% level..

If finding this situation, I will have to show you where and what that problem area is being.
( If so . . .Aren't you one HAPPY camper now ? )

73's de Edd . . . . .

Its true . . . . I am an insomniac . . . . . but I don't lose any sleep over it !

.
 
Last edited:

george2525

Jan 30, 2015
170
Joined
Jan 30, 2015
Messages
170
Hi

Ok so the volume control does nothing at all, no matter where I turn it. The level is always the same, maybe 20% of full volume or so. It is as if the resistance is stuck as maybe the wiper has detached inside maybe?

Anyway I am about to start trying some more tests now. It took me 2 hours just to access the part :(

Im thinking to short the connections to see if I get the loudest volume. Its been a while since ive done this lol. Have I forgot anything here?
 
Last edited:

george2525

Jan 30, 2015
170
Joined
Jan 30, 2015
Messages
170
Ok so I shorted the connections and the volume went up. Ordered a 10K version of a similar pot (original was around 4.7K) which hopefully will do the trick. Thanks for the help guys
 
Top