CASIO XW-PD1 - Weak distorted sound on built-in loudspeaker

Synth Repair
,
1

[Casio] [XW-PD1] – [Weak distorted sound on built-in loudspeaker]

Hello,

I acquired this Casio “Trackformer” thing. It’s a ridiculous looking toy but treasured by some people I guess. I had been intrigued by what it can do, but aware that it cannot be synced or really integrated into any sequencing setup. My intention is to add a USB MIDI host and drive 5 pin MIDI input so I can use it as a “tone module” for an external sequencer.

It had 2 issues that made it junky enough to buy it cheaply off eBay.

The first issue was a broken slide potentiometer. I ordered a close but not exact replacement (bourns) PTA4553-2015DPB502. After bashing the dead slide pot together with the new one, it seems to work.

The second issue is the built-in loudspeaker is very distorted. I’m going to assume the speaker is not damaged, and try to diagnose the amplifier on the analog board.

So… it sounds not very loud, and square wave clipping distorted.

I cannot find any, ANY documentation of this product besides the user manual. I can’t find any photos of a disassembled XW-PD1, no write-ups. This is a first.

Is there a source for this information? I can trace the audio signal and try to determine what stage it’s getting distorted at. I’m going to assume it’s a faulty amplifier IC.

If it is of interest I can share some photos of the internals.

Ben

• Model & revision/OS:
• Symptoms (what changed, when):
• Tests already done (voltages, parts replaced):
• Photos / audio clips:

2

To follow up, here’s what I have found so far.

This is one of Casio’s products using the “Dream” DSP chips. (like other goofy toys for wannabe DJs like the Yamaha DJX series).
It uses the TA8227APG car amplifier IC, in bridged mode to drive the internal speaker, so I assume one of the channels has failed. I have ordered some from eBay.
It uses the 433M5W and 450M5W to power the low voltage logic ics.
I have tapped the USB port and am adding a Teensy 4.0 as a USB host to support 5 pin MIDI, making this much more useful as a studio tone module.
Obviously the loudspeaker, while big and buff for a groove box, is underpowered and silly. But just for fun I hope I can get it pumping out the beats. Otherwise I will remove it and make the device lighter to carry (but less stable if you go to town on the pads).

1 Like