YBA CD2 DAC Chip Identification Help

[Tubologic]

YBA CD2 DAC Chip Identification Help (SOLVED)

I'm currently working on a YBA CD2 player with a defective D/A converter chip on the analog output board. It's a 24-pin SMD package device mounted on the bottom side of the PCB, in position IC9.
Problem is that the manufacturer has carefully erased (sanded) all the markings and the chip is no longer identifiable. I contacted YBA by e-mail but (unsurprisingly) never got any reply. Now I'm stuck and can't repair the player due to this part identification issue. If anybody here has more accurate informations (no guesses please: there are many DAC's using the same package) about the exact type of DAC used in the CD2 it would be greatly appreciated.

 

[stephensank]

According to a review I found, this player came out back in 1993, claiming to have an 18bit dual dac. Being 28pin SOIC package, it is most likely an AD1865 or PCM1700. You can confirm if it is one of these by locating where the power supply pins are on the datasheet diagrams for each chip, versus where you find supply lines coming to the chip on board.
Incidentally, it looks more like the chip is painted, rather than sanded, so you might try a solvent like MEK to see if it will come off & reveal the number.

 

[abraxalito]

The picture shows a 24pin SO package, not 28pin. I went to TI, Cirrus and AD's sites and searched for 24pin SOIC DACs with a long history, turned up no leads.

 

[stephensank]

Oh, heck, you're quite right. I somehow thought I read 28pin. And, yes, I am not seeing any 18bit dual dacs I can think of, off hand, that ever came in 24pin soic. YBA did allegedly claim it was a custom chip, but I find that extremely hard to believe.

 

[maxpou]

Hi,
I was really surprised, this is a sanyo chip. Send me a PM. Maxpou

 

[Tubologic]

Hi,
I was really surprised, this is a sanyo chip. Send me a PM. Maxpou

Yes, I also received confirmation it's a SANYO (NOT Custom !!) dual 18bit D/A converter including 8fs oversampling filter. All the "customization" YBA made was to put a small adhesive copper foil on the chip (which I removed) and... sand off the markings to make it unidentifiable ! Thanks to all who helped. Problem solved.

 

[stephensank]

Ah, makes some sense. I didn't even think of the LC78835, which is what it must be. Pretty cheap circuitry for such an overpriced player.

 

[abraxalito]

I agree - can't see anything to recommend that chip. Compromised oversampling filter (43 taps in first stage) presumably to keep die size down?