eproms wont work unless in sockets Wtf!

eproms wont work unless in sockets Wtf!
by Nerdy Nick on 2007-11-09 (#28061)

Well if you saw my other post i couldn't get Eb cart working when i soldered the eproms directly to the board (even though it was a mess)
But i cut them off and put them in a socket cart i made and it all worked..

So seeing as i had a working one in front of me i tried to make another one without sockets.. I was super careful and the soldering was probably the best ive done And it didn't work :evil:

So i desoldered the eproms and soldered some sockets in, then stuck the eproms straight back in and it worked...

Is it possible my eproms wont work unless there in sockets???

Also if do use sockets does anyone have and tricks to get it back in the case without cutting it?

by tepples on 2007-11-09 (#28062)

Sockets make bend-the-pin-up rewiring jobs more reliable.

Sockets also probably add a tiny bit of resistance. Particularly with PowerPak, people have found that some memories act more reliably with some resistors on the data lines.

by kevtris on 2007-11-10 (#28071)

tepples wrote:
Sockets make bend-the-pin-up rewiring jobs more reliable.

Sockets also probably add a tiny bit of resistance. Particularly with PowerPak, people have found that some memories act more reliably with some resistors on the data lines.

Naah it's not that. The resistance will be in the milliohms range. It's most likely some stealth shorts... like between the chip pin that is lifted up and the hole underneath or similar. That or there might be some kind of wiring flaw too that happens to be corrected when it's socketed.

by teaguecl on 2007-11-10 (#28073)

tepples wrote:
Sockets also probably add a tiny bit of resistance. Particularly with PowerPak, people have found that some memories act more reliably with some resistors on the data lines.

I think you're talking single digit resistance (in ohms) added by a socket, that doesn't seem likely to add any kind of benefit does it? You really need to get up to 5K or more before you're going to notice any real difference in behavior.
I think your other suggestion, that getting a good pin lift is easier with a socket, is much more likely. Or, a bad solder job.

by peppers on 2007-11-10 (#28077)

in his last thread he said he tryed a differint game and it worked but them he went back to earthbound witchout sockets then trouble

Did you try EB0 in the socketed one and have it working?

if not my advice is the same as in the last thread

if you did it would seem ether
1 you left the eprom wimdow exposed and it got UVifyed
2. bad or incorrect soldering

note: I have made a direct solder eb0 cart witch worked but I used flashroms not that is matters

by Nerdy Nick on 2007-11-10 (#28078)

Yeah the problems not eb0 its working fine..

and im 110% its not the soldering it all looks really good. ( i can see my reflection in every joint)

The eprom is made by ST and is M27C2001

does any body have any neat ''tricks'' to get a socketed eprom inside the cart without wiring each eprom pin individually to the socket?

by sepi on 2007-11-13 (#28204)

If you live in EU area, leadfree solder could be the problem.

Tepples suggestion worked with my devcart, i used Atmel flash ROMs and they refused to work until i fitted 470 ohm resistors to PRG D0-7

Someone may have suggested this already, but you could use ohm meter to check all connections, and don't use beeper range it often gives a misleading results.