Part Indentification On Casiotone Ct-640 Keyboard

[Frederick65]

Hi. I'm trying to identify a part on the power supply of my electronic piano above. The part looks like a disk capacitor, is yellow, and has three leads. The two outer leads have insulators on them. It is stamped "222" on it. I have buzzed the part out. All the leads appear "shorted" together. A similar part on another part of the PCB does not have all leads shorted together. I think this part may have caused failure of my keyboard, but I'm not sure. I thought it might be a thermistor, but I can't find any thermistors with three leads. Casio wouldn't help me, and there are no schematic/repair manuals on line. At this point, I just want to know what this part does or is. Thanks.

 

[Harald Kapp]

Welcome to EP.
A good photo of the component in question will greatly help us (and you) to identify it. More than a thousand words

A few possibilities:

• ceramic resonator
• filter
• 3 terminal capacitor

It will also help to know in which context the component is being used. In the power supply, in the digital section, in the analog section? A photo of the PCB are around the component will be helpful, too.

 

[73's de Edd]

Sir Frederick65 . . . . .


Wherefore art thines forthcoming photos ?

See if this Casiotones power supplys construction is being about of that older vintage and methodology of construction used for your unit .
The separate main power transformer is being the YELLOW star unit to the left.
I suspicion your part to be located in the YELLOW circled area.
WIth your description and testing of the unit, it might need to have two leads be pulled up from the board to assure that there is no shunted circuitry path that is giving your shorted ohmmic condition.
What I suspicion the device to be, is a dual disc ceramic " Y " safety capacitor, that has a common center lead that goes to ground and either of the side leads are being .0022 ufd capacitors.

SIMILAR ? CASIOTONE UNITS PHOTO REFERENCING . . . . .



73's de Edd

.

 

[Frederick65]

Thank you 73's de Edd. Sorry it took long. I've been moving and was recently between lodgings. The part is marked "EF" on circuit board and is between the power jack and diodes and the blue electrolytic capacitor. I will look up what you've already suspected. Once again, thank you for your help. At this point I'm on a learning curve. Also: why are there insulators on both sides of this part? Also, all of the leads of this part ARE SHORTED TOGETHER. I have no voltage beyond the power jack and the anode of both of the diodes. That is why I suspect it might be the part responsible for my keyboard's dying. BTW: I looked for a schematic and couldn't find it. Casio was no help either.

 

[73's de Edd]

Sir Frederick65 . . . .

In seeing that pic , your unit is newer and has a separate power inpit at the black connector to the left.
Its also at a MUCH lower voltage .
What you then have yourself there, IS a dual .0022 ufd ceramic capacitor with its common center lead BUT with some additional ferrite choke beads on each side lead.
That combined C factor derived from the capacitors and the L (inductance) values drived from the wire lead and ferrite beads make an somewhat effective filter of Radio Frequency Interference and Electro Magnetic Interference, either trying to come into your unit or that your unit might be trying to radiate outwardly from your unit. Silk screened component assignment . is being . . . EF . . . as in Electromagnetic Filter.
They must be wired in differently manners . . . . for both of the two seen units . . . so you still need to lift outside leads to effectively test the one that tests as being "shorted" .
I HEAVILY feel that both will be good units.

Looks like your CASIOTONE board's very foreground info is revealing that it is REALLY being of Matsushita lineage.

Need some more info as to what the unit can and can't do, in order to get into more involved troubleshooting, unless it's just plain DEAD.

73's de Edd

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