socketing '92 rt sbec question (leftover holes)

[MNmopar]

I'm looking to socket my '92 rt sbec in the next day or so and need the definitive answer on which 4 holes should be left out of the new socket (there are 4 less pins on the replaceable socket than there are on the stock computer).

When looking at the "top" of the board (the side that the harness plug plugs into), there are two heat sinks under the main plug, then the chip is to the lower right of that in the corner. When re-socketing this thing, do you ignore the 4 pins closest to the heat sinks or the 4 pins closest to the corner of the board?

Please don't post up "thinks", I'm looking for "knows"... The situation's already been confused on the other forum with people posting that it should be done both ways, and I need to find the difinitive answer, not more guesses.:thumb:

http://i593.photobucket.com/albums/tt11/prochilus/P1020704.jpg

[cordes]

that's interesting. I didn't realize that the 92+ stuff was a 32 pin chip. Why don't you just look up the data sheet for the chip you have and the chip you'll be using?

[MNmopar]

that's interesting. I didn't realize that the 92+ stuff was a 32 pin chip. Why don't you just look up the data sheet for the chip you have and the chip you'll be using?

Where would I find the data sheets, in the fsm?

I'm at my parent's house in another state and was going to have my dad (who is an electrician) socket this for me until I remembered the pin issue, so I don't have the fsm handy. Is there a place online that would have that info?

[cordes]

Yeah, just google the part numbers and they should come up first thing.

[ShelGame]

The left-most pins (8 pins total) are left open when you're putting a 87C257 chip in place of the Toshiba chip. There are no datasheets available for the Toshiba chip. The 'extra' pins were used for a factory development module similar to an Ostrich. I use 3 of the 4 as control lines for my flash module.

Since I've never seen a datasheet for the Toshiba chip, I have no idea why it needs 4 more pins than the 87C257. I suspect it's a 64k chip since it has A15 going to it where the 87C257 doesn't need that last address line.

[cordes]

That's very interesting. I just did a search and I found them referenced in several places, but I couldn't find the actual data sheet or much about them. I did find a place where you could order a similar chip, but that's not saying much. This is a very interesting thread for sure.

[MNmopar]

That's very interesting. I just did a search and I found them referenced in several places, but I couldn't find the actual data sheet or much about them. I did find a place where you could order a similar chip, but that's not saying much. This is a very interesting thread for sure.

Good, I thought I might have been going crazy not being able to find any data sheets either.

And thank you Shel-game, that's what I'll do then. I have the chip out and just cleaned around all of the connections, and tomorrow I'll ask my dad to solder the new socket in to the "right" leaving the left 4 holes empty. (I trust a professional electrician more than I do myself when it comes to small stuff like this)

Thanks guys, I appreciate the input and hopefully next time someone is searching for this info they'll find this thread.:)

[ShelGame]

Good, I thought I might have been going crazy not being able to find any data sheets either.

And thank you Shel-game, that's what I'll do then. I have the chip out and just cleaned around all of the connections, and tomorrow I'll ask my dad to solder the new socket in to the "right" leaving the left 4 holes empty. (I trust a professional electrician more than I do myself when it comes to small stuff like this)

Thanks guys, I appreciate the input and hopefully next time someone is searching for this info they'll find this thread.:)

Doh! Nonono....my bad. The RIGHT 8 most pins. Brain fart on my part. I meant the right 8 pins and typed in left. Too much egg nog I guess...

[MNmopar]

"Too much egg nog I guess... " Haha, well it is Christmas day, so you have to make allowances I guess!

Got it, and I got your pm too Rob, thanks for letting me know. I haven't soldered anything yet, so no harm, no foul.

I'll slide it all the way to the left leaving the right 4 holes open.

Thanks guys, I appreciate it!

[MNmopar]

Just to make sure Rob, you keep saying 8 pins would be left over, do you mean 4?

The stock chip has 16 per side (32 total) and the replacement socket that I'm putting in has 14 per side (28 total) 32-28=4, right?

Or are you saying that the replacement chip that I'll get from you (or fwdp, or whomever) would have only 12 pins per side, leaving 8 original holes unused?

[ShelGame]

Just to make sure Rob, you keep saying 8 pins would be left over, do you mean 4?

The stock chip has 16 per side (32 total) and the replacement socket that I'm putting in has 14 per side (28 total) 32-28=4, right?

Or are you saying that the replacement chip that I'll get from you (or fwdp, or whomever) would have only 12 pins per side, leaving 8 original holes unused?

If you'll notice, there are actually 4 unused pads even with a 32-pin Hitachi chip (they're to the right of the chip). So, when you put a 28-pin chip in place of the 32, there will be a total of 8 unused pads, all to the right of the chip.

[MNmopar]

Should have known you were way ahead of me Rob, I wasn't thinking about anything other than the pins that were part of the original chip.:)