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Devcarts/repros arn't working :( (im at wits end)
http://forums.nesdev.com/viewtopic.php?f=28&t=3660
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Author:  Nerdy Nick [ Sat Nov 03, 2007 3:18 am ]
Post subject:  Devcarts/repros arn't working :( (im at wits end)

Hi everyone,

I have just recently got into the into the whole nes hardware thing and have spent heaps of $$$ on a burner, eproms, and eraser, doners etc and have got sh*t to so show for it :(

Ok, so first i tried making a Earthbound zero cart per these instructions

Earthbound Zero:
- Board required: NES-TKROM-10 (Tecmo Basketball works)
- Use 2 D27C2001D-15 or equivalents
- Remove mask roms
- Bend up pin 1, 2, 24 & 30 on PRG eprom
- Solder into place of the masked rom.
- Tie pins 1 & 32 together (+5)
- Tie pins 22 & 24 together
- Tie pin 2 & pin 24 hole together
- Tie pin 30 & pin 1 hole together
- Bend up pins 1, 2, 22, 24, 30 & 31 on CHR eprom
- Solder into place of the masked rom.
- Tie pins 1, 31 & 32 together (+5)
- Tie pin 30 & pin 1 hole together
- Tie pin 24 & pin 2 hole together
- Tie pin 2 & pin 24 hole together
- Tie pin 22 & pin 31 hole together


It was the first time i had soldered anything so i wasn't suprised when it didn't work.

Then i tried the mod on this page http://beigerecords.com/cory/Things_I_M ... _2005.html

To avoid the whole mess of desoldering i simply snipped the old chip then soldered the the new one onto the old legs And it worked!!

So with my new confidence i tried another Eb zero and it still doesn't work and i have no clue why.

I burnt the new chips and soldered them onto the existing snipped legs and lifted and soldered the legs as per the guide.

i even went out and bought a multi meter to test it and everythings connecting properly ( although the mutli meter takes slightly longer with some of the connections).

I have never felt so frustrated in my life so and help/advice is really appreciated

Author:  drk421 [ Sat Nov 03, 2007 9:12 am ]
Post subject: 

Did you verify the data on the EPROM before you soldered it?

Did you cut the tracks or bend the pins up?

Can you post some pictures?
Closeups of the cut tracks or bent pins would be best.

Author:  leonk [ Sat Nov 03, 2007 3:31 pm ]
Post subject: 

I don't recomment soldering to old pins. You need to remove the old lets, so you see holes, and then drop/solder eprom in place.

Since these boards are double sided, some traces are on one side, and some are on the other. Even though you verified with a voltmeter, it means nothing. I've seen verified connections that are good enough for the voltmeter, but not good enough for the actual eprom chip!

Also, you gotta use good wire. 30 guage single strand wire, which some people use, is junk and should be avoided. If you don't have access to good wire, take an old PC floppy cable and use the strands of wire from there.

Keep the wire as short as possible.

Author:  Nerdy Nick [ Sat Nov 03, 2007 5:44 pm ]
Post subject: 

Image

Image

Image

Image

Image

Author:  Lloyd Gordon [ Sat Nov 03, 2007 6:49 pm ]
Post subject: 

I don't want to make you feel bad but that looks way too disorganized. It's really hard to check your work that way. I would buy a $15 RadioShack desoldering iron with a sucking bulb attached. It's good enough to desolder the ROM's on a cart.

Then before you solder in a socket (low profile is best so you won't have to dremel the case) either cut and re-route the proper traces or bend out the proper pins to connect to the proper traces. Take your time and spend a lot of time checking each connection.

In the end you'll have a much more reliable devcart. Also it's nice to be able to take the EPROM's out to reprogram them.

Author:  blargg [ Sat Nov 03, 2007 7:21 pm ]
Post subject: 

An Ohm meter should work fine. As long as the resistance is say 15 Ohms or less, the connection is good. You can't just check that the correct things are connected; you also have to be sure the incorrect things are NOT connected. Sure, it may be a mess of solder, but if you carefully check each connection and check for shorts, you can find and fix any problems.

Author:  peppers [ Sat Nov 03, 2007 7:21 pm ]
Post subject: 

Lloyd Gordon wrote:
I don't want to make you feel bad but that looks way too disorganized. It's really hard to check your work that way. I would buy a $15 RadioShack desoldering iron with a sucking bulb attached


I find useing desoldering braid works better for removeing these types of things its cheaper and better for this propose

Author:  Nerdy Nick [ Sun Nov 04, 2007 2:49 am ]
Post subject: 

blargg wrote:
An Ohm meter should work fine. As long as the resistance is say 15 Ohms or less, the connection is good. You can't just check that the correct things are connected; you also have to be sure the incorrect things are NOT connected. Sure, it may be a mess of solder, but if you carefully check each connection and check for shorts, you can find and fix any problems.



if some of my connections take a bit longer to connect on the multi meter does thing mean there bad? ie

when x pin is read the multi meter instantly gives a beep

while y pin takes a few seconds

Author:  loopy [ Sun Nov 04, 2007 8:26 am ]
Post subject: 


Author:  blargg [ Sun Nov 04, 2007 1:09 pm ]
Post subject: 

Nerdy Nick wrote:
if some of my connections take a bit longer to connect on the multi meter does thing mean there bad? ie

when x pin is read the multi meter instantly gives a beep

while y pin takes a few seconds

You might be connecting across a capacitor in case Y. Or just not piercing through the rosin flux on the surface of the solder at first. What resistance do you measure across Y? What if you reverse the meter probes (connect red where you had black, and vice-versa)?

Author:  Nerdy Nick [ Sun Nov 04, 2007 2:19 pm ]
Post subject: 

Well im not sure if i measuring resistance, i think im measuring continuality
or something, when theres not connection at all it gives 0L and on all my connections it gives 0.000,

btw i did make a tsrom socket cart that i think works, will eb run off tsrom

Author:  peppers [ Sun Nov 04, 2007 2:24 pm ]
Post subject: 

^yes but you would need to add a battery if you want to save witch would require some additional rewireing,nothing too bad though

Author:  Nerdy Nick [ Sun Nov 04, 2007 10:42 pm ]
Post subject: 

Ok,ive gone over and over and ive found a bunch of pins that look a bit sus and take a bit of work to make connection on the multi meter.

I try and do something this weekend, i hope to god this is the problem because i really cant see anything else wrong with it

Author:  Nerdy Nick [ Wed Nov 07, 2007 1:09 am ]
Post subject: 

Fixed everything but it still doesnt work..

the only thing i got happening was a flashing brown, green and pink screen which stoped anyway after i switched it off.


maybe its something with how im splitting/burning the rom...

im using the earthbound prototype rom, removing the header with a hex editor, then seperating it with windows command tool which leaves me with 3 files, prg chr and crc

ive only been burning the prg and chr, is the crc important?

Author:  Nerdy Nick [ Wed Nov 07, 2007 10:20 pm ]
Post subject: 

bump

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