开云体育

All the manuals I listed are spoken for. Thanks to all who expressed
interest.

Steve

On Mar 4, 2018, at 6:48 AM, Dave Daniel <kc0wjn@...> wrote:

I took a look and that's what I see. The R364 on the divider board is a 1k resistor and the manual calls out a 100 ohm resistor.

DaveD

On 3/3/2018 6:32 PM, Brian Bloom via Groups.Io wrote:
I'm replacing out-of-tolerance resistors in my 2901 time mark gen and ran across a 1k resistor where the SM says it should be 100R. The resistor in question is R364 on the divider board directly behind Q347. This isn't a model number dependent resistor, but my SN is B041433.

Does anyone have a 2901 they can pop the top on and have a look?

Thanks,
Brian

On 4 Mar 2018, at 22:46, Dave Daniel <kc0wjn@...> wrote:

I seem to recall that someone on this list was or is making pull tabs for 7000-series plug-ins.

DaveD

On 3/4/2018 3:41 PM, Dave Voorhis wrote:

I snapped the pull tab on my 7D20. The knob is intact, but the plastic to which it attaches, isn’t. Anybody parting out a 7D20 and willing to sell the plastic tab?

I snapped the pull tab on my 7D20. The knob is intact, but the plastic to which it attaches, isn’t. Anybody parting out a 7D20 and willing to sell the plastic tab?

Are you using 1.44MB disks in 720kB drives?

Dave Casey

On Sun, Mar 4, 2018 at 10:35 AM, Szabolcs Szigeti <szigiszabolcs@...

wrote:

Hi,

Now here is an interesting problem. I have two 2402A Tekmates, for my

2440

and 1430a. I was using one of them with an USB floppy emulator, which

works

just fine. I have actually never used the floppy drives (both have HDDs),
but I finally did find my stack of 3 1/2 floppies, so I wanted to try and
use the floppy on the other one, as it is way more col thank the cheep

USB

emulator :-), and it did not work. It accesses it, but then gets an
abort-retry-fail. Ok, no problem, probably the drive is bad. Swapped to

an

other one, the one that actually came out of the other Tekmate, when I
installed the USB drive. That didn't work either. Hmmm. Get a 3rd drive,

no

luck. Now let's try the floppies in the other Tekmate. They don't work
either!

I really don't believe that I have 3 failed drives, and the controllers

are

OK, because the emulator works. Scoping the drive line don't show

anything

out of order, I see the data coming, drive rotates, head moves, etc. So

the

only thing I can think is that there has to be some BIOS or whatever
setting about the size/type that was lost when the NVRAM battery failed.

I

have hacked in external batteries, so that is ok. Obviously, the drive is
set up as a 1.4M drive in the setup.

Am I missing something? Is there any other setting that needs to be

there?

I really don't believe that all 3 drives are bad, but unfortunately I

don't

have any other means to test. I have already swapped cables, drives, even
controller chips.
Not a big problem, but it is bugging me now.

Thanks,

Szabolcs

On 4 Mar 2018, at 15:30, Chuck Harris <cfharris@...> wrote:

The ROM's on the A5 board contain everything they need to
know about being a 2467B, 2465B, 2445B, or 2455B.

The A5 controller's are interchangeably the same. You can
take one out of any member of the 24[4,5,6]5A or B family,
and swap around. The only significant difference has to do
with the separate Display board on A's, and early B's. You
can swap a controller/display board from an A into a late B,
and vice versa, if you want... [The "A" controllers have some
ROM omissions for the extra diddly stuff that the "B" can do,
and some changes in the calibration routines, battery voltage
sensing...]

The way the A5 controller knows what scope you have is by
reading the P/J512, pin 11, and pin 32. Pin 11 goes with
a jumper, W120, which if missing is a 2445B/2455B, if grounded,
is a 2465B.

P32 determines whether the scope is a 2465B, or a 2467B. The
significant difference (board wise) between a 65, and a 67, is
the HV power supply board, the 67 board has the control voltages
necessary for the MCP. As a result, the 67 Board grounds P32,
and passes the signal through the A1 motherboard to P/J512, P32,
on the A5 Controller board.

The only schematic where Tektronix forgot to erase this information
is the analog control <2> schematic for B050000 and above in the
2465B/2467B manual (070-6863-01).

Someone once said: "What a tangled web we weave, when first we
practice to deceive." One of the girl poets, as I recall. Emily
Dickinson maybe?

I hope you won't use this information for evil.

-Chuck Harris

Raymond Domp Frank wrote:

On Sat, Mar 3, 2018 at 02:59 pm, Sergey Kubushyn wrote:


A5 ROM has nothing to do with calibration -- that is stored in NVRAM -- but
it adds those higher sweep rates that 2445B doesn't have i.e. it changes the
scope identity.

ISTR that enabling 500 ps/div horizontal speed to a 2445B just takes adding a jumper near the edge of the main board, at one of the connectors. Sorry, don't remember exactly where and I have no doc. where I am at the moment. I trust this'll ring a bell with someone on this forum who has the details.

Raymond

On Sat, Mar 3, 2018 at 02:59 pm, Sergey Kubushyn wrote:

A5 ROM has nothing to do with calibration -- that is stored in NVRAM -- but
it adds those higher sweep rates that 2445B doesn't have i.e. it changes the
scope identity.

ISTR that enabling 500 ps/div horizontal speed to a 2445B just takes adding a jumper near the edge of the main board, at one of the connectors. Sorry, don't remember exactly where and I have no doc. where I am at the moment. I trust this'll ring a bell with someone on this forum who has the details.

Raymond

I'm replacing out-of-tolerance resistors in my 2901 time mark gen and ran across a 1k resistor where the SM says it should be 100R. The resistor in question is R364 on the divider board directly behind Q347. This isn't a model number dependent resistor, but my SN is B041433.

Does anyone have a 2901 they can pop the top on and have a look?

Thanks,
Brian