"bg" wrote in :

Both channels on the verticle front end are damaged. One dual FET
follower is a definite (Q1297). It is tek part number 151-1090-00. I
haven't seen one yet using google. Is there a replacement or two
discretes out there that will work?

They would have to be matched,else you get an offset.

check this out;
http://www.sphere.bc.ca/test/tek-parts/tekparts2.html
it appears they have some 151-1090's for sale.
they also cross ref to a "2N5911 family".

I noticed that the pinouts for the chip following the dual FET
(U1290), are
incorrect. Doing a diode test on the chip, there are several pins
mislabeled. The external circuitry seems to go to the pins as shown on
the schematic, but the internal circuitry ohms out to different pins.
This would only be an issue if you ohm out the chip like I did to see
if the chip was bad. If anyone is interested, I can post what seems to
be the correct internal circuitry.
bg



the 155-0078-xx is used in a lot of different scopes,several 7000 series
plug-ins,too.

--
Jim Yanik
jyanik
at
kua.net