Re: Need Help Fixing A Couple of 2445 Scopes



I haven't seen a 2445, but I think it is pretty much like a 2465. The 4-pin
connector does indeed connect to the back of the GPIB board.

I think that the other connector goes to the power supply board A2A1. There
are two connectors that come up from the bottom of the case from the main
board. They have different pin spacing and are keyed. They connect pretty much
side by side to the A2A1 board.

There are some photos on the eevblog forum from my teardown of my 2465BCT in
the category "Test Equipment", topic: "Tektronix 2465B oscilloscope teardown".
The url is
which contains the photos of some of my teardown. Part of that is pictures of
how the 4-pin connector is connected and pictures of the inside after the A3 /
A2A2 boards have been removed. You can see the large white connector coming up
from the bottom. The wires go inside the metal post to keep the options from
pinching them and the two connectors that come up from the bottom connect to
the A2A1 board.

You also have the fan power line that connects to the feed through capacitor
on the back, near the fan and the processor board.

There are four power wires. The two on the bottom go from the 115/230 switch
to the bottom two lugs on the A2A1 board. The two from the fuse holder go to
the top two lugs. The wire coming out of the end of the fuse goes to the lug
on the right (facing the A2A1 board), and the other goes to the lug on the
left. That doesn't quite match up with the schematic, but that is the way mine
was wired and it works. You have to be careful, those power wires are
difficult to get in place with no working room (loosen the back panel a bit
will help). It is easy to damage the fuse holder. I broke mine, but super glue
fixed it. There is also a ground wire from the A2A1 board that connects to the
back of the case.


Here's the problem. There are more insides, inside since this scope has
the GPIB Option, the problem is that I don't know where all of the wires go.
I think I got all but one cable plugged in in the right places, but I have
one end of one cable left, and I can't figure out where it goes.

The four conductor cable (all white wires) from the mode light panel
above the CRT, Does it plug into the four conductor terminal down low on the solder side of the GPIB board?

The cable that really has me stuck is a (seven?) single row conductor
cable with all white wires. One end seems to go on the Expansion
Motherboard that fits inverted on the top of the scope chassis, next to a 34
ribbon connector cable that goes to the A5 Control Board. Where does the
other end of this cable go? I can't seem to see any open plugs where it would fit.

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