I've recently received a 1chip superCIC kit and build it, but I've got a weird issue I can't figure out. For some reason the 5V line drops to to 3~4V and doesn't boot the console. I can't think of anything that might cause that and have checked every connection at least trice and redone the whole thing at least once. Edit: I've noticed by shortening the wire I get only minor voltage loss (from +-15 to +-5 CM, going from +-3.9V to 4.8V), still won't do anything though. Strangely enough that only happens on the 5 volt line and I've tried changing wire. All other connections to the SNES's board seem to hoover around 0.2 to 0.5V, including LED connections, with the exception of those going to pin 1 and 2 of the CIC pads (+-1V and can't get a solid read) and the S-RGB pin 9 leg (4.7V) Edit2: I connected to the wires for pin 2 and 7 to the respective cartslot places for soldering less cramped and less chance to ruin things (and because 2's pad is ripped off)
Edit3: New problem... I accidentally left it on for a while (15 minutes I reckon) and now there is no loss in the 5V wire anymore but I most likely killed a IC (probably superCIC) on the stripboard as their is 0 to near 0 volt read on the connections that goes to the CIC pads (1, 2, 8, 10 and 11) and the same goes for pin 111. Although the S-rgb pin 9, CIC pin 7 and TC1+ both give a 5V reading Edit4: I'm think I might have killed the SuperCIC, could someone verify that? Or give me a way to test it to be sure. edit5:What I can deduce is 7404 isn't working correctly and that the SuperCIC has nothing going out.
It is quite difficult to see, what the problem is. Your initial problem sounds like a short between Vcc and GND somewhere (could also be inside a defective IC). The measurements you have taken now are useless at the most points. E.g. on the 7404 you have clocks at in- and outputs. The measurement at SuperCIC pin2 does not makes any sense too: there is also a clock there. If the SuperCIC is working, you have alternating signals at pins 8, 9 and 10. The 0V at pin 11 of SuperCIC says me that the console is hold in reset by the SuperCIC. If I were you, I would resolder EVERYTHING on a new board. Which schematic have you used? An use also alternative solder points for the CIC, like the reset button for CIC8, the cartridge slot for CIC1,2,7 and 11 and the S-APU pin 100 for CIC10 (there is a via right next to the pin)
I've redone everything (for the second time) and it still doesn't boot, you said that on pin 8 their should be alternating signals while I get a stable signal on that. I've tried switching the non-SuperCIC IC's with no luck (I socketed them). And what I now noticed after the rebuild it that the TC1+ gives a lower voltage (0.5V) that I think should be 5V. Also I use these schematics: Tomorrow I'll remap the voltages and hope on that it shows more. Edit: after checking the results from using different IC's the original 7400 seems to be faulty. edit2: Some behaviours in the voltage seem weird to me
You cant measure for voltage on the 74 logic chips, the signal coming in and out of those isnt constant. Your DMM will just give an average
Ahh, so most data from that is pretty much useless in seeing if it functions properly let alone see the issue. So what are some things I could try to fix the issue or at least have some diagnostic data that could possibly show the issue?
This probably goes without saying but just to make sure. Did you add a 10kohm resistor between CIC pad 8 and GND?
No, that might be the issue. I simply used the components in Bad_Ad's kit and followed the top schematic. And the guides I've read/skimmed don't seem to mention it (but now looking on google most seem to have it).
Yeah, it depends on whether you choose to remove the original CIC or just disconnect some of the pins. If you just disconnect some of the pins then the resistor is not needed.
Ahhh, that explains a whole lot. Time to look I have a spare laying about. BTW don't mind me asking but could you explain the actual use of that resistor?
To be honest, no. Sorry but I don't really know the technical reason behind it but as far as I'm aware the original CIC has an internal pull down resistor on pin 8. If you remove the original CIC then you need to replace the pull down resistor or the cartridge CIC will not allow the game to boot. Maybe someone else here could elaborate or correct any assumptions on my part.
I've added the resistor, now I've gotten back to the original issue... The 5V line drops to 3V but at this point with largely different components (all but SuperCIC and caps).
Have you checked all the pads for the original CIC with a multimeter for shorts to each other or GND? You would be surprised, all it takes is a hairs width of solder to make a short. Easy to miss with the naked eye.
I looked, I found something. Ground and 9 were shorted (but seeing as they are both ground it should be). And Ground had a resistance with both the 5V line of 1366 ohm and pin 4 with 1366 ohm. But that also seem to normal (at least compared to the 2 SNES's I have laying here for parts). And 1, 2 and 10 both had some connections that were above 160.000 ohm, but I highly doubt that would be an issue.
