I got the same at first after I had closed everything back up. Thinking it was a short I undid everything again and it worked spot on. Couldn't see a short so I put it back together and it worked without problem. Now I haven't used my PSX for a few months and when I turned it on, I got the same cracking and popping. A quick tap of reset and its clear again.
Anyway, here's a pic of the mod and its wiring. Sorry for the slightly blurry shot ^_^
EDIT: Heres a little more detailed info for those who have asked for it. (Wall o' text warning!)
The IC I used was the Texas Instruments DIT4096
. I did a search on eBay for "TSSOP adapter" and I found a local seller selling the needed 28 pin TSSOP to DIP adapter PCB. The PCB I used has a big ground pad underneath the IC so I cut the trace to make it into 2 pads and used them as convenient places to solder GND and VCC to.
The solder points on the PSX pcb were derived from looking at the specs for the original mod
and tracing the relevant IC pins back to the closest VIAs (for slightly easier soldering). I did solder one extra wire and that was for the DIT4096's reset line and that was soldered to the AK4309's reset line (thats the DAC in the PSX).
Now the hard part. Like I mentioned in an earlier post, (for me) finding information on the Toshiba part was impossible and my exploits with the Cirrus Logic part were not bearing anything audible. Luckily I was able to find the datasheet for the DAC (the aforementioned AK4309). Now this is where the detective's hat went on...
First of all the Gamecube mod uses the same chip as the PSX one (even a similar arrangement for the supporting IC) and the instructions for that mod (unlike the ones for the PSX) had labelled the pins on the main IC so deciphering where to solder the pins on the TI part was relatively easy (watch out, some pins on the Toshiba are active high while they are active low on the CL and TI parts). The hard part however was how to configure the TI chip as there was no info on the Toshiba chip I couldn't work out the correct settings. Then it hit me... the DAC! A quick google for the part revealed the datasheet
and in that was the info I needed. The DAC has few configuration pins and out of sheer luck the one value I couldn't work out (the MCLK frequency) was one of those settings and a quick probe about with the multimeter soon gave the answer (384 • fS by the way, which can't be selected on the CS part in hardware config mode, but can on the TI part).
I don't know why (I'm no electronics expert) but the TI chip (and I guess the CL chip too) don't need the extra glue logic IC that the toshiba part requires.
After that it was just a simple case of soldering it all in and powering it on... it worked first time!