开云体育

Andy, if you need lots of pictures of the cal fixtures let me know I have a
-01 and -02 here in the lab. I am also in process for a test board for a
7854. I had a unit arrive today.... destroyed by the shipper and bad
packing. It will at least give me something to test on. I'll be in to board
layout shortly.

On Mon, Jul 26, 2021, 10:35 PM Andy Warner <andyw@...> wrote:

I have a 7904A, that I intend to keep in good working order.
However, I've not seen many cal fixtures on the market and reckon the
prices are only going to go in one direction for the near future. I am
planning to design one or more cal fixture(s) using modern components. I
figure I'll learn a lot more about the scope in the process, have some

fun,

share the designs, and hopefully others can find the work useful.

Step 1 in this process is a simple passive breakout board for the

backplane

connections, to allow me to experiment and prototype things. I checked

the

archives and did not see an existing design, so I cooked one up. The
v1 boards are just back from fab and I have uploaded some photos here:
/g/TekScopes/album?id=266487 I am in the process of
mounting the board in a parted-out 7A26 module frame that I had on-hand,
will update more photos as I continue (assuming there is interest.)

This board brings out the high speed signals to BNCs and the low speed
signals to screw connectors. The low speed signals are grouped roughly by
function (power, readout, IEEE-488, misc.) Be aware that for this

version,

I did not match the high speed signal path lengths, or worry too much

about

impedance.

I'll probably create a project page somewhere with the eagle files, the
BOM, and progress as I work on cal/test fixtures, if anyone wants to

follow

along. Look for an update when I get organized enough to do that.

--
Andy

I have a 7904A, that I intend to keep in good working order.
However, I've not seen many cal fixtures on the market and reckon the
prices are only going to go in one direction for the near future. I am
planning to design one or more cal fixture(s) using modern components. I
figure I'll learn a lot more about the scope in the process, have some fun,
share the designs, and hopefully others can find the work useful.

Step 1 in this process is a simple passive breakout board for the backplane
connections, to allow me to experiment and prototype things. I checked the
archives and did not see an existing design, so I cooked one up. The
v1 boards are just back from fab and I have uploaded some photos here:
/g/TekScopes/album?id=266487 I am in the process of
mounting the board in a parted-out 7A26 module frame that I had on-hand,
will update more photos as I continue (assuming there is interest.)

This board brings out the high speed signals to BNCs and the low speed
signals to screw connectors. The low speed signals are grouped roughly by
function (power, readout, IEEE-488, misc.) Be aware that for this version,
I did not match the high speed signal path lengths, or worry too much about
impedance.

I'll probably create a project page somewhere with the eagle files, the
BOM, and progress as I work on cal/test fixtures, if anyone wants to follow
along. Look for an update when I get organized enough to do that.

--
Andy

Quick update to close the loop. I went through the components related to the NE555 timer and concluded that it was, indeed, a dead IC. I injected a 20.48 kHz signal at the output of the NE555 and the display came to life. I replaced the IC and its working great. Calibration was pretty much spot on as far as i can tell with my limited testing. Thanks again for all the feedback. Another TM504 lives along with the PS503A, FG502 and of course the DM502 that came with it. The fourth slot has a storage box that had an unused temperature probe & manual and a variety of test leads, banana jumpers and some odd push-in BNC jumpers with molded plastic ends that fit into a female BNC and will accept a male BNC on the back side of the plug. Looks great along side the TM503 . . .

Rich

On 26Jul, 2021, at 6:22 PM, Michael W. Lynch via groups.io <mlynch003@...> wrote:

Get the comb binding punch and the installer as well. Two pieces are necessary.

--
Michael Lynch
Dardanelle, AR

On Jul 26, 2021, at 18:06, Jeff Dutky <jeff.dutky@...> wrote:

?Also, a number of my Tek manuals, including the one that I just printed out from a PDF, were punched for both comb binding and three ring binding. Most of the manuals that I have with three-ring holes punched are BIG (e.g. the service manuals for the 475 and 2236). For the thinner manuals I can see where you might want to keep several of them in a big D-ring binder, but for the thick ones I don't see how that is practical. Does anyone know what the intent of this was?

-- Jeff Dutky

Also, a number of my Tek manuals, including the one that I just printed out from a PDF, were punched for both comb binding and three ring binding. Most of the manuals that I have with three-ring holes punched are BIG (e.g. the service manuals for the 475 and 2236). For the thinner manuals I can see where you might want to keep several of them in a big D-ring binder, but for the thick ones I don't see how that is practical. Does anyone know what the intent of this was?

-- Jeff Dutky

The way I read it is a single lot...2 units for one money.
But it really isn't very clear.
Fabulous price (currently)!

One early unit - SN B071082
One late unit - SN B315353