Merritt68 2/13/2018 6:42 PM
Polytone 102 preamp NSKE4093
I'm looking at this Polytone Amp (Late 1979 vintage) and on the preamp schematics there are what appear to be JFETs that are labelled as NSKE4093. I suspect this is an obsolete National Semiconductor part. On the circuit board, one of these has been removed (it has obviously been desoldered and removed). So, assuming that it is possible that this was done by a hack, I'm simply trying to find a data sheet for the part so I can find a suitable replacement should it be appropriate. I've spent several hours searching the web for any mention of this part number and have found nothing. Anyone here have any information as to the specs for it? I can provide more info if needed. Thanks, Merritt
 
The Dude 2/13/2018 6:46 PM
My bet is that it's a 2N4093. Case style? Pics? Oh, and welcome to the place!
 
DrGonz78 2/13/2018 10:51 PM
Perhaps it can be related to a NS PN4093 FET? [url]https://www.semicon-data.com/transistor/tfet/pa/PN4093.html[/url] They are still selling these old stock here... [url=http://www.galco.com/buy/National-Semiconductor/PN4093]PN4093 - National Semiconductor - Transistor | Galco Industrial Electronics[/url] Edit: BTW "The Dude" Abides again... 2N4093 and PN4093 are the same thing in this case. Check this huge National Semiconductor FET data BOOK!!! [URL="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjmrYPO26TZAhVSxWMKHajOAhsQFggwMAE&url=http%3A%2F%2Fmirror.thelifeofkenneth.com%2Flib%2Felectronics_archive%2FNatSemiFetDatabook1977_text.pdf&usg=AOvVaw1XZfLSRY9v2aaaHRucj5vv"]https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjmrYPO26TZAhVSxWMKHajOAhsQFggwMAE&url=http%3A%2F%2Fmirror.thelifeofkenneth.com%2Flib%2Felectronics_archive%2FNatSemiFetDatabook1977_text.pdf&usg=AOvVaw1XZfLSRY9v2aaaHRucj5vv[/URL] Double Edit: Look at page 22 in the National Semiconductor Book PDF file. Halfway down on the right side of page "KE4093 = Industry part number" and "PN4093 = National Semi. Part."
 
Merritt68 2/14/2018 4:55 AM
Thanks Dude. It is a TO92 case. And between you and DrGonz, I'm looking a little weak on the searching side. Between the two of you I have what I need for now.
 
Merritt68 2/14/2018 5:00 AM
As I noted for The Dude, you guys are making me look weak in the search department. And I had looked at that huge NS data book and in my frustration, never thought to use a CTRL-F search for just 4093. In any case, thanks to both of you for the quick and helpful replies. I'm on the case now.