Sunday, January 17, 2010

Analyse.. don't Destroy (a Casio PV-1000)

I'm not a console collector nut, I'm a audio chip collector nut. There are countless game consoles and computers out there that I dont care much about because they all contain the same chips. (AY-3-8910 is nice, but you can only have so many of them).

What I'm looking to acquire at this point are the most obscure ones which contain custom/unique sound generating chips. You've heard about the CASIO PV-1000 before?

Don't worry, only the most die hard console collectors did. And they would die for it too. There are very very few such consoles out there and I got mine a bit by chance, and it was an impulse buy.

At 300$ (ebay), you just can't afford to ruin it can you? (I'm not a movie producer). And I look forward to its resell value once im done with it. Thats where the challenge comes in... how do I take a device that comes with just a NTSC-J RF adapter and get good enough audio results with it? (the RF channels on North american and Japan dont match... dont try)

The closest I got to getting a picture/sound from the default unit as is was to use a ANALOG/DIGITAL USB TV tuner, which had by chance a NTSC-J mode:

Not that bad, but, the audio was horrendous, and really not usable for my tests. However I've hacked nearly all my consoles in order to have separate composite video/audio from RCA jacks, so on top of some test equipement, i've got a few hunches on how to solve this cleanly.

the RF box is tied to the main motherboard in a very clean way:

A few minutes with my multimeter, from top to bottom:
1)9VDC (current for the amplifiers in the RF sections i assume)
3)Composite Video Out.. YAY!
4)GND (same as 2)
5)Audio Out...  w00t!

Connecting Aligator jumpers to truncated ends of a RCA and to the pins 3,4 and 5 did provide me with a temporary solution, but surely isnt very practical for a longer term analysis.

Oups, where did the RF box go? (in a safe place in case I resell it and the buyer really is after lots of  pain and suffering).

Much better.
 From the outside:

Enjoy the OK quality outputs:

Saturday, January 9, 2010

Meet my new friend the logic analyser!

Its time to step my game up. So I've decided to acquire the immese value for money Saleae Logic Analyser. This baby will allow me to analyse and record a bunch of stuff that really cant be handled with a sound card and an oscilloscope alone. (namely serial digital audio prior to being sent to DACs)

As a test to see if everything works, and that i can get sufficient time resolution on this, ive done a simple setup which consists in a 4Mhz clock and a Hex inverter (74LS04). I done my recording test using 24Mhz on my MacBookPro's USB2 port. And im quite happy with the results. Not bad for 15 minutes of unboxing the thing!