Post by thread:[EE] Shelf Life of Semiconductors

Hi, Before becoming a software guy (1989 when I went to graduate school in CS), I was into electronics big time. I had a lot of electronics components like chips, transistors, diodes, resistors, capacitors, LEDS, 7-segments displays and so on. They have been lying in a box since 1989. Now I am back and want to use those components. My questions is do these components have a shelf life? Almost all the ones I am using now work fine but will they keep working for their manufacturer claimed life span? I probably will use them in a non-professional setting. I am specially interested the shelf life of the chips I have. Some of them are priceless for me. For example I have a 64 pin DIP MC68000 (0.1" pins) chip that I used in my undergraduate final project. It is humongous in size and it looks funny now. I would like to use it in some project some day. There are some other chips I have which may be hard to find now. Thanks for any comments. -Hasan

> time. I had a lot of electronics components like > chips, transistors, diodes, resistors, capacitors, > LEDS, 7-segments displays and so on. They have been > lying in a box since 1989. Now I am back and want to > use those components. My questions is do these > components have a shelf life? Almost all the ones I Well... they should continue working until you kill them (for solid state devices)... they shouldn't degrade/oxidise... some caps may leak with time... > am using now work fine but will they keep working for > their manufacturer claimed life span? I probably will > use them in a non-professional setting. Ah... then it doesn't matter does it... test it... if it is spoilt, bin it.. else use it.. > I am specially interested the shelf life of the chips > I have. Some of them are priceless for me. For example > I have a 64 pin DIP MC68000 (0.1" pins) chip that I > used in my undergraduate final project. It is > humongous in size and it looks funny now. I would > like to use it in some project some day. There are > some other chips I have which may be hard to find now. wow... 64pin dips... that's loooong... you really should keep that in a display case... cheers.. with metta, Shawn Tan.

At 08.45 2005.08.30 -0700, you wrote: {Quote hidden}>Hi, >Before becoming a software guy (1989 when I went to >graduate school in CS), I was into electronics big >time. I had a lot of electronics components like >chips, transistors, diodes, resistors, capacitors, >LEDS, 7-segments displays and so on. They have been >lying in a box since 1989. Now I am back and want to >use those components. My questions is do these >components have a shelf life? Almost all the ones I >am using now work fine but will they keep working for >their manufacturer claimed life span? I probably will >use them in a non-professional setting. > >I am specially interested the shelf life of the chips >I have. Some of them are priceless for me. For example >I have a 64 pin DIP MC68000 (0.1" pins) chip that I >used in my undergraduate final project. It is >humongous in size and it looks funny now. I would >like to use it in some project some day. There are >some other chips I have which may be hard to find now. > >Thanks for any comments. I think that besides electrolitic capacitors, you should consider all of them as new components. The electrolitics instead may exhibit high losses, at least the first few hours you power them up.

On Tuesday 30 August 2005 10:45 am, Hasan A. Khan scribbled: > Hi, > Before becoming a software guy (1989 when I went to > graduate school in CS), I was into electronics big > time. I had a lot of electronics components like > chips, transistors, diodes, resistors, capacitors, > LEDS, 7-segments displays and so on. They have been > lying in a box since 1989. Now I am back and want to > use those components. My questions is do these > components have a shelf life? Almost all the ones I > am using now work fine but will they keep working for > their manufacturer claimed life span? I probably will > use them in a non-professional setting. Similar here -- hundreds of TTL chips, some Z80 cpus, EPROMS, etc from 1985-ish. What I've found is that the legs on the chips are partially corroded/tarnished so solder does not adhere to them well. In a breadboard they work fine though. With a little sandpaper they solder fine and work well. However, it is easy to damage the pins when cleaning them up and I've found there more of a hassle for the low cost of TTL, so I just end up buying new ones. Cheers, -Neil.