Keithley 616 component ID

On Wed, 07 May 2008 13:11:38 -0400, JW put finger to keyboard and composed:

I'm guessing they are specially selected Intersil parts.

Have a look at the IT500-IT505 dual N-channel J-FETs:

Maybe someone has an Intersil catalogue or databook from around that time (early 1980s ???).

- Franc Zabkar

Thanks Franc, Intersil makes sense. It's starting to look like I'll need a donor unit.

On Fri, 09 May 2008 11:00:30 -0400, JW put finger to keyboard and composed:

I would think that you could refer to the schematics in the manual ...

... and find a modern op-amp and dual J-FET with much better specs.

See

You may even be able to get a free sample:

Here are two dual N-channel J-FETs that may fit the bill:

Here are more choices:

You can request samples here:

- Franc Zabkar

I have a couple donor Keithley benchtop DMM boards.. I can dig them out and take a look for those parts,if you like.

Thanks Franc, but I was never much good at figuring out what specs are important when cross-referencing other than voltage and current. Especially with something as sensitive is this piece.

Thank you for your generous offer, PhattyMo, but I spent a few hours digging through our "graveyard" and found the pieces I need in another piece of equipment.

Ah,Glad to hear that you've found what ya need! Finding (older) parts can be a serious headache,if not impossible sometimes.