68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Straightening bent pins on 68040 chip
Posted by: David Cook on 2022-06-17 12:08:44 I'm always on the lookout for full 68040 chips to upgrade my LC 475 and Performa 630 series computers. The other day, a bent chip appeared on eBay for $30. It isn't a recent mask, but it is rated for 33 MHz. As the seller described, the chip has quite a few bent pins. Fortunately, no pins are broken and only a few have bends in multiple directions. Most of the pins were easily straightened gently with tweezers and a headband magnifying visor. The next step is to align the rows and columns. For that, I use 0.1" female header connectors. They are long strips and have just enough slack to accept randomly offset pins. The high-end 3M strips are part number 929974-01-36-RK. But, you can find much cheaper knock-off connectors. I insert a row at a time, nudging any pins that don't allow the next row to fit. Because the connector holes are evenly spaced, and because the connector width snugly fits against the next connector row, this tends to align both rows and columns simultaneously. After filling up all the rows, I gently wiggle each connector off and then repeat the process rotated 90 degrees for a tiny bit more improvement. Although the chip pins are now much straighter, there are still a few imperfections and misalignments. You can use tweezers again or perform a test fit on a computer. It took about 10 tries to firmly seat the chip in the LC 475 socket. I gently wiggled the chip, pushed down slightly on one side, lifted in back up, and repeated the process pushing on different points and different angles. Eventually, all of the non-conforming pins reached the socket tolerance. My patience was rewarded with a fully working 68040! Hope this helps others, David
Posted by: jwg1962 on 2022-06-17 12:11:23 Hi David, Thanks for posting this. Also, I have used a .7 or .9 mm mechanical pencil without lead in it to straighten the pins.
Posted by: Skate323k137 on 2022-06-17 13:48:46 Hi David, Thanks for posting this. Also, I have used a .7 or .9 mm mechanical pencil without lead in it to straighten the pins. I learned this trick from Twitter, could have used this in the 90s so many times 😆
Posted by: macuserman on 2022-06-17 13:51:59 I actually have a bent pin on a nubus card I want to straighten and I just ordered these in an attempt to fix it a couple days ago, should be there when I get home tonight. But I didn't have anything slender enough to fit in there without messing up other pins. The pencil trick I'll have to remember but unfortunately my pin is curved as it I think started by being bent to the side then I compressed it into a curved shape attempting to install it not realizing the pin was bent. Fingers crossed I can salvage it.... https://www.amazon.com/dp/B078HGGTF5?psc=1&ref=ppx_yo2ov_dt_b_product_details
Posted by: David Cook on 2022-06-17 14:03:39 Also, I have used a .7 or .9 mm mechanical pencil without lead in it to straighten the pins. Great tip! I've just ordered a variety pack to try this myself.
Posted by: cheesestraws on 2022-06-17 14:18:00 Thanks for posting this. Also, I have used a .7 or .9 mm mechanical pencil without lead in it to straighten the pins. This is a very sensible idea. Will have to give it a go!
Posted by: jwg1962 on 2022-06-18 09:47:56 Thanks. You just need to make sure they have that little extension on the end.
Posted by: 68kPlus on 2022-11-17 18:12:36 I have a badly bent 68040. One of the pins were bent so badly it was all the way to the bottom. Upon trying to straighten it, one of the pins broke off. Any ideas on putting it back on? I'd like to have a working 68040 to try with a Mac at some point (don't have any yet).
Posted by: Byrd on 2022-11-17 19:02:30 @68kPlus check the 68040 developer notes, maybe you'll be lucky and find out one the broken pin is one of the many ground pins you can live without out. If it appears important and the pad remains I'd solder it back on, don't push it too hard into the socket when inserting. I'll probably break off if you remove it again but chances are that isn't an everyday occurrence :0 JB
Posted by: SiliconValleyPirate on 2022-11-30 12:19:36 Wow, that brought back a few memories. The 68040 pins are relatively robust if you are careful. I once had a 68040 pin pigtail (bend back and around on itself) on me when I tried to put it in the socket. I managed to straighten it by working slowly and carefully over about an hour. Some good tips here and I especially like the mechanical pencil one!
Posted by: 840quadra on 2022-12-07 11:05:33 Great post! Mine will arrive today and hoping I don't have to do too many repairs to get it online! I do have the trusty mechanical pencil standing by just in case!
Posted by: 840quadra on 2022-12-07 15:01:23 Done! Ended up using a basketball air fill nozzle and a pin socket from an old hard drive controller to straighten out the pins on my 68040. Working well so far!
Posted by: David Cook on 2022-12-07 17:10:26 Ended up using a basketball air fill nozzle and a pin socket from an old hard drive controller to straighten out the pins That's fantastic!
Posted by: Addicted on 2024-08-16 20:22:37 The old wirewrapper tool finds new life, here. It's good for a first pass, then the single-row header does the detail work.
Posted by: David Cook on 2024-08-16 20:44:08 The old wirewrapper tool finds new life, here. It's good for a first pass, then the single-row header does the detail work. Nice! Good tool recommendation.
Posted by: Addicted on 2024-08-16 21:53:13 I have looked around for old bottom-cavity PGA ZIF sockets, thinking I could use my heavily reworked but operational LC475 as a test bed for salvaged 040 chips. They do a fine job of gently massaging warped pins back into line. Take the standard socket out of the 475, put in a ZIF, and away I'd go with a tray of dubious salvage parts. Those sockets appear to be rare as hens' teeth, as the saying goes, unless I want to contract a firm to make a lot of 1,000 for me. Haven't found a junked eval board with one, nothing, nowhere.
1