jmratkos wrote:no worries. I re-programmed another set of eproms (while waiting for the original set to be erased) and attempted to mount the NTRQ eprom directly onto the SNROM board (this time adding the wires to jumper thru-hole 1 to pin 30, thru-hole 2 to pin 31, thru-hole 24 to pin 2, and tacking a wire from the nub of pin 24 on of the eprom and running it to pin 16 for ground), but I have still not been successful in getthing anything other than a grey screen to appear when powering up the famicom
Oh no!
Your jumper description is correct. So considering that you are are using Famicom HW and following ne7's guide, it should work; the NTRQ mod seems the easiest of the two. The only advice I can offer is general tips:
1.Clean the board, removing any flux. I use rubbing alcohol, 90% grade. Did the cart work before the mod? Clean the card edge contacts, they can never be too clean.
2. Recheck you work. Verify all the wiring, more then once I have made a bone headed mistake swapping connections. Wiggle the wires a little, could be a broken wire at the place you stripped it. Don't trust yourself, VERIFY EVERYTHING
3. Use a magnifying glass and look for solder bridges and shorts. Clean up with solder braid.
Are any board traces damaged? De-soldering can be ruff on circuit boards, excess heat can lift or break a trace. If this is the case, you can carefully repair it with some 30 gauge wire. Follow the bad trace a little ways back, to a good place to solder. Clean the solder mask off and tack the wire to that spot . Connect the other end to the component.
4. Cold solder joints can 'look' OK, but still not work. Some times you can tell because they are dull and do not 'flow' to the soldered parts. You can try testing the continuity with an ohm meter. Probe on either side of the joint, I.E. from the copper on the board to the component lead; so you are testing through the solder joint. 0 ohms=GOOD. The short cut is to assume there is a cold joint and go back re-heating all the joints, use solder braid to remove the bulk of the old solder, use new flux and if needed a bit more solder. Then goto to step 1.
5. If all of the above fails, then you need to consider that the EPROM wasn't programmed correct. In which case you are back to square one, so this is a last ditch effort. Do make sure that all the above steps check out before starting over!
With all of the above, you can pop the cart back into the Famicom and try it as you go. With a large project, I like to do these checks as I go, after a build session. Troubleshooting a whole board with >100 solder points can be a night mare
With PR8 there is an issue with the save state in the ram having bad data at first boot, but I don't think this is the case with NTRQ
jmratkos wrote:I have not taken the steps to add the CR2032 coin batteries (still waiting for those to show up in the mail). I would be very appreciative if you coulld post the values for the resistors and diodes that I need and where they go.
I'll gather the info and post to this thread soon, have to look over your photos closely.
jmratkos wrote:I've gone through all of the pages on his blog, but unfortunately I still feel like I'm missing something
Not to worry, you'll get it tracked down, just takes a little time!