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On Thu, 29 Nov 2018 19:38:13 +0100, you wrote:

BTW you can get the standard ground lead with the probe side spring
and crappy alligator clip on Digikey for $2.65:
<>

Thanks, since I'm not using the alligator clip, I don't care about the
quality of the clip.

The one with the marginally less crappy alligator clip can be had for $10:
<>

Ouchie....

BTW: you *can* buy clips that look identical from McMaster-carr.
Problem is that they are not copper, they're 18-8 stainless or zinc
plated steel. Not sure that I want to try soldering to them.

This is assuming that the clips can be had in the right size.

Harvey

ST
On Thu, Nov 29, 2018 at 7:20 PM stefan_trethan <stefan_trethan@...> wrote:

Harvey,

I have found that for me the most practical solution is to use BNC
adapters and directly solder to the BNC end.
Yes, this means you also need to make the center connection in that
manner, but that is really more practical anyway.

I have about 2 inches of silicone or teflon wire soldered to the BNC
end (red/black) and a 0.025 square single connector.
The square connectors plug into pins soldered on the PCB, or more
often into Hirschmann micro Kleps:
<>

I also have a set of these BNC adapters with just wires connected to
them, which I can solder directly to boards (and leave connected for a
while).
The BNC adapter body is protected with a section of silicone tubing to
prevent shorts to ground.
It looks similar to this part from Lecroy (PMK):
<>

I haven't used a probe to poke on something directly for probably
years, and haven't used a "witch hat" hook tip for even longer.
They really aren't very practical for my line of work.

There is an impact on signal fidelity of course, but often times I bet
I have it better than a regular ground clip lead, and if needed I also
have sockets I can solder on a PCB to stick a probe in directly.

ST




On Thu, Nov 29, 2018 at 6:48 PM Harvey White <madyn@...> wrote:

I'm going to build a number of ground clips for the P6100 series
probes that terminate in a 0.025 square connector.

I have those connectors, but I don't have a good source of the clips
for the scope probe body.

A good example of the probe would be a P6105. I'd also like to see if
there's an inexpensive source of the slip on 0.025 probe tip adaptors
as well, although those might be a 3D print option.

It does occur to me that I may be able to make a whole probe slip-on
adaptor that bypasses the need for the ground clip, but I'd like to
see if I can do the standard ground clips.

Harvey

BAMA has one for the 6125a, not close enough ?

On Thu, 29 Nov 2018 19:19:49 +0100, you wrote:

Harvey,

I have found that for me the most practical solution is to use BNC
adapters and directly solder to the BNC end.
Yes, this means you also need to make the center connection in that
manner, but that is really more practical anyway.

I'll have to think about that, don't have any of them, either. (maybe
one or two that came with a 7A11?)

I have about 2 inches of silicone or teflon wire soldered to the BNC
end (red/black) and a 0.025 square single connector.
The square connectors plug into pins soldered on the PCB, or more
often into Hirschmann micro Kleps:
<>

I have a half ton of 0.025 pin connectors. I use 20 pin adaptors to
the HP 16702B, otherwise, they can be test points.

I also have a set of these BNC adapters with just wires connected to
them, which I can solder directly to boards (and leave connected for a
while).

The way those things go, I'd be breaking wires. The boards move
around a lot in development.

The BNC adapter body is protected with a section of silicone tubing to
prevent shorts to ground.
It looks similar to this part from Lecroy (PMK):
<>

That was my option for a complete slip-on adaptor.

I haven't used a probe to poke on something directly for probably
years, and haven't used a "witch hat" hook tip for even longer.
They really aren't very practical for my line of work.

Depends on what I'm looking at. In normal scope repairs, I normally
will use a dip-clip or the hook adaptor for discrete parts. For my
own SMT projects, I have to design in the test points (frequently).

There is an impact on signal fidelity of course, but often times I bet
I have it better than a regular ground clip lead, and if needed I also
have sockets I can solder on a PCB to stick a probe in directly.

Similar to what I do with the logic pods.

So is the center pin in a BNC the same size as the probe tip in the
probe? That would be convenient.

Just checked, the probe tip appears smaller.

I see something happening with the 3D printer, maybe.....

Thanks

Harvey

ST




On Thu, Nov 29, 2018 at 6:48 PM Harvey White <madyn@...> wrote:

I'm going to build a number of ground clips for the P6100 series
probes that terminate in a 0.025 square connector.

I have those connectors, but I don't have a good source of the clips
for the scope probe body.

A good example of the probe would be a P6105. I'd also like to see if
there's an inexpensive source of the slip on 0.025 probe tip adaptors
as well, although those might be a 3D print option.

It does occur to me that I may be able to make a whole probe slip-on
adaptor that bypasses the need for the ground clip, but I'd like to
see if I can do the standard ground clips.

Harvey

BTW you can get the standard ground lead with the probe side spring
and crappy alligator clip on Digikey for $2.65:
<>

The one with the marginally less crappy alligator clip can be had for $10:
<>


ST

Harvey,

I have found that for me the most practical solution is to use BNC
adapters and directly solder to the BNC end.
Yes, this means you also need to make the center connection in that
manner, but that is really more practical anyway.

I have about 2 inches of silicone or teflon wire soldered to the BNC
end (red/black) and a 0.025 square single connector.
The square connectors plug into pins soldered on the PCB, or more
often into Hirschmann micro Kleps:
<>

I also have a set of these BNC adapters with just wires connected to
them, which I can solder directly to boards (and leave connected for a
while).
The BNC adapter body is protected with a section of silicone tubing to
prevent shorts to ground.
It looks similar to this part from Lecroy (PMK):
<>

I haven't used a probe to poke on something directly for probably
years, and haven't used a "witch hat" hook tip for even longer.
They really aren't very practical for my line of work.

There is an impact on signal fidelity of course, but often times I bet
I have it better than a regular ground clip lead, and if needed I also
have sockets I can solder on a PCB to stick a probe in directly.

ST

I'm going to build a number of ground clips for the P6100 series
probes that terminate in a 0.025 square connector.

I have those connectors, but I don't have a good source of the clips
for the scope probe body.

A good example of the probe would be a P6105. I'd also like to see if
there's an inexpensive source of the slip on 0.025 probe tip adaptors
as well, although those might be a 3D print option.

It does occur to me that I may be able to make a whole probe slip-on
adaptor that bypasses the need for the ground clip, but I'd like to
see if I can do the standard ground clips.

Harvey

First, and quite importantly, you don't have a 2445,
but rather a 2245, they are very different scopes.

Second, the 2245 scope you show has the readout close
enough to the proper position to eliminate any major
issues.

That tiny little difference on the left edge is accounted
for by calibration. The amount a scope needs to go past
the left or right graticule lines is usually not specified,
but amounts to enough so that you can always reach the
graticule line at all sweep speeds.

The calibration section of the manual will show you how
to correct it.

-Chuck Harris

Mattis Lind wrote:

I just received one of his clocks several weeks ago, I had to keep checking back as he seems to run out quickly. It appears to have more functions than any other one I looked at.

John

Given that there is no CLIP available, it is unlikely
you will ever know what they did... unless you pull the
attenuator out, remove its covers, and look for yourself.

Pretty easy work with any stereo dissection microscope.

The 50 ohm resistor was probably serving two purposes,
first as a dampener for reflections that might end up on
the probe's coax, which is much lower impedance than 1M,
and second as a fuse.

To blow that resistor, your friend must have over voltaged
that input quite a lot. It probably involved the power
line.

-Chuck Harris

arnoldniemeier via Groups.Io wrote:

Jan de Rie who makes the clock kits is Dutch but lives in Seattle. I bought one of his kits a few months ago.

When I click on the link on imgur it shows a 2245 not a 2445!

Roger

On 29/11/18 09:36, Mattis Lind wrote:

Commenting on what machineguy59 wrote, it may very well be a general
calibration problem, maybe I should check for some kind of general
calibration procedure?

Step 1: measure the PSU voltages and compare them with those in the service manual.
Step 2: look at the A5 control board for corrosion from capacitors.
Step 3: there are two key voltages on the A5 board upon which all other controls depend. Ensure those are correct.

The latter two are well described elsewhere in this forum and on many websites.

Den tors 29 nov. 2018 kl 05:01 skrev Chuck Harris <cfharris@...>:

Does the readout display in the proper position?

I cannot tell for sure if the readout are in the correct positions. However
if I look on images on the net for Tektronix 2445 my readout seems to be
slightly more to the left. Compare my scope:


With this scope:

*
<>*

Commenting on what machineguy59 wrote, it may very well be a general
calibration problem, maybe I should check for some kind of general
calibration procedure?

-Chuck Harris

machineguy59 via Groups.Io wrote:

There is an adjustment on the mainboard that "centers" the horizontal

display. It may also effect the readout, moving everything as a whole.
These are usually adjusted during calibration. It concerns me that yours
seems to have drifted. That drift may indicate other problems with the
calibration of the scope.

On ?Wednesday?, ?November? ?28?, ?2018? ?05?:?27?:?26? ?PM? ?CST,

Mattis Lind <mattislind@...> wrote:

I have this nice tektronix 2445. It works quite well, but it has one

small annoyance. The trace doesn't go to left edge, regardless of setting
of position knob.

Is this something that can be corrected?

/Mattis

Guess what someone did with your scope? switched on the 50 ohms (or left it on),
used a 1:1 probe or a direct connection, and applied the voltage....

That was the first thing I thought too, but that is NOT the case. I'll explain...

The input of the scope is 1M, 50 and 75 ohm. With the burned resistors the scope still had
the 50 and 75 Ohm terminators in tact (measured with an ohm meter on the input and selecting trough scope menu)

But the 1M section is open circuit. When I replace those 50 Ohm resistors the 1M is back and the scope works normal.

So the 50 Ohm value is a bit misleading here. This is not the 50 ohm line terminator.
It is in series with the signal path. Behind that resistor is probably some sort of diac, zener or
whatever to ground... And I really like to know what that "whatever" is :-)

Does the readout display in the proper position?

-Chuck Harris

machineguy59 via Groups.Io wrote:

I hadn't seen those! I still like the clock, though. That benefits the VintageTEK Museum so I might pick one up anyway. Thanks!

John
________________________________
From: [email protected] <[email protected]> on behalf of Dave Brown <davebr@...>
Sent: Wednesday, November 28, 2018 9:32 PM
To: [email protected]
Subject: Re: [TekScopes] AVR Scope Clock

You don't want no stinking clock! You want to play tennis on your oscilloscope!


Dave

You don't want no stinking clock! You want to play tennis on your oscilloscope!


Dave

Hope you'll get your clock, John. I doubt whether it'll be this one though, but others seem available.
Good luck!

Raymond

There is an adjustment on the mainboard that "centers" the horizontal display.? It may also effect the readout, moving everything as a whole.? These are usually adjusted during calibration.? It concerns me that yours seems to have drifted.? That drift may indicate other problems with the calibration of the scope.

Thank you Raymond...
I did try emailing the dutchtronix email address but didn't see the southhollandtrading.com site. Looks like the same guy. I sent an email to that address, as well, and will try giving that number a call, as well.

Thanks for the help!

John
________________________________
From: [email protected] <[email protected]> on behalf of Raymond Domp Frank <hewpatek@...>
Sent: Wednesday, November 28, 2018 6:07 PM
To: [email protected]
Subject: Re: [TekScopes] AVR Scope Clock

John,
Have you tried mailing jdr@... (apparently, yes) or andyr@...?
The southhollandtrading.com website shows a phone number: (503) 410-9850.

I have one of their clockd, I like it and no, it"s not for sale...

Raymond