Category Archives: Karaoke

Magic Sing Karaoke Microphone Tear Down, Part 2

I’m back!  I have a tendency to pause projects for lengthy periods of time, so here is part 2 of my Magic Sing Karaoke Microphone Tear Down.  This time, we’re actually going to look inside the microphone, which serves as a remote control as well.

On the outside we see a nicely designed case with buttons, and an LCD screen.

Upon power up, the LCD reads “SYNC”.  When you turn on the base station, they connect and the LCD says “Karaoke” which is the default menu option.  The communications is two-way, what happens on the screen is reflected in the LCD.  When you enter a song # or browse for a song and select it, the song # is displayed.

Let’s open it up!  (Carefully)!

We see one lengthy PCB with a silver box on the end.  That silver box indicates RF shielding…So that means the radio is under that hood.

Confirmed!  These chips are a TI CC2400 transceiver (2.4ghz), an undocumented CASUH retaw1-05, and an SST 1Mbit flash chip.  The retaw1-05 is a RF modem chip, but could not find a datasheet on it.

The back of the radio board is boring, but has a couple of connectors.  Moving on…

How the two boards look when separated.  At the left side of the long board is an ATMEGA48.  It is right under the LCD so I’m going to guess it is the button/LCD controller.  I’m pretty sure we can assume that the Atmel also connects to the retaw1-05 radio modem chip.

 

They made a failed attempt at covering that ATMega48..

Below we can see the codec chip (AIC311). This chip is responsible for converting the audio from the microphone into a digital stream.  It has some other neat capabilities such as pitch changing, base, treble adjustments, etc. By the location, and the traces that run out to the right, I can extrapolate that this chip feeds directly into the bottom black connector going to the radio board.  The Atmega48 surely has some control lines going to this as well.

To Do:

It would be really neat if I could sniff the packets coming out of that CC2400.  I’m also not sure if both the RF Modem and the CC2400 are generating radio frequencies. The datasheet (two page only) that I could find on the Retaw says it is 2.4ghz but it also says it can interface with a CC2400.  There are many products from Korea that use this chip alone for both audio and data (phones, head phones, etc), so I’m a bit confused why they use both chips.

Magic Sing Karaoke Microphone Tear Down, Part 1

I bought this Magic Sing Karaoke microphone system many years ago and my family and friends have enjoyed and some times been annoyed by it quite often!  It truly is a really neat gadget..  I’ve got a plethora of photos of the inside, the outside and the on screen displays.

The microphone base has 2500 songs built in, and has several add on slots for song chips that are available online for about $60 a pop.

The base also has an SD card slot, but it is not for songs.  It is only used for storing user content, photos, backgrounds, movies and songs recorded live.

The system includes two cordless microphones that also each act as a remote control.

The model # I have is the ET19KV.  I originally paid $499 for it!  But that was like eight years ago!

Under the top cover of the base unit we find the slots for expansion chips.  I’m impressed by the number of slots.  Some song chips have 200, 400 songs!  But most have between 60 and 100.  The songs are of the MIDI type.  You can watch the video at the end of the article to hear the actual sound quality.

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The rear of the base has the output connections:

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The wireless microphone antenna:

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Let’s open it up!  Don’t tell my wife!  At least I put it back and no extra screws were left!

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Interesting things in here.  The big black parking lot sized chip on the left is an FPGA!  The chip on the right is a flash memory chip, which holds the circuit design for the FPGA.  If you’re not familiar with FPGAs, they are essentially a blank canvas for creating eletronic circuits using logic gates.  They have millions of gates or connections that can be configured into just about any digital circuit imaginable.

 

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I’m very curious about the squigly lines shown above.  These traces, they were intentionally designed that way, I wonder why?

The chip on the bottom left of the below picture is the NTSC/PAL video encoder/decoder.

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Another big chip!  This one is a Sunplus DVD/Mpeg1/2 decoder.  I suppose this is for playing movies off the SD card:

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You can store Karaoke Movies on an SD Card and play them on the MagicSing.  There is special software called MagicSing Encoder that you need to use to get the best results.  There are lots of sources for Mp3/CDG files that can be converted to the video format usable on the MagicSing.  You can scrounge up CDG discs at yard sales etc and rip them to your hard drive if you have the right CD reader.

 

Here is the song chip.  This chip holds 200 songs.

The card edge connector is a 40 pin, 2 position, male variety.

The contacts are about 0.050″ (1.27mm) pitch.  Hard to measure!  The card is .031″ thick.

The actual chip inside is a NOR Flash variety.  Some information about NOR vs NAND memory chips:

https://focus.ti.com/pdfs/omap/diskonchipvsnor.pdf

The connector looks like a Harting 40 pin Motherboard to Daughterboard:

https://b2b.harting.com/ebusiness/en_us/PCB-connectors-Micro-Card-Edge-Connector/391899?showProducts=1

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This is a Spansion S29Gl064N90TF104 64 megabit NOR flash chip, storage space is 8 megabytes.  It is a 48-pin TSOP.  22 Address pins, 15 data pins. It can operate in 8 bit or 16 bit address/data communications.

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This is a 40 pin edge card connector.  I’ve got a temptation to hook this up to my mbed enabled STMicro nucleo board and download the data to see whats in it!  The nucleo board is an ARM powered development board that costs $10 and has plenty of IO pins to connect to this chip.  I had thought seriously about trying to decode whats on this chip but in the end it will be fruitless.

Some work has been done by some smart fellas on NAND flash chip bit banging through the FTDI break out board.  I wonder how this could be adapted to the NOR chip?

https://github.com/cyphunk/ParallelFLASHDumper

https://recon.cx/2014/slides/Reverse%20Engineering%20Flash%20Memory%20for%20Fun%20And%20Benefit.pdf

Now for some screen shots.

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