Re: What's the rubber pad under the 2465?
The pad wasn't available until after the 2465 had run its
course, having been introduced with the B models... after
serial number B050740, I believe. It was available as a
modification kit for all models.... and all cabinets are
interchangeable, so some mixing and merging has certainly
occurred over the years.
Its purpose was two fold. It is pretty popular to put the
2465 on the shelves that are above most commercially made
workbenches. And those shelves are usually too short to
allow the 2465 to sit upon its feet, assuring proper ventilation..
The 2465's fan sucks fresh air through the holes in the cabinet
in places where it is needed, so undoubtedly some scopes were
damaged by having the holes around the vertical preamp hybrids
blocked by the carpeting that is commonly on these instrument
shelves. The black plastic keeps the scope up enough to allow
air to flow where it must.
The secondary purpose is to prevent damage to the cabinet that
would make it hard or impossible to remove. The vertical preamp
covers have hard points where the springy grounding clips are
mounted to the back of the preamps. If you bend the cabinet
in this area... even a little..., you won't be able to slide it
by those hard points, without cutting the cabinet.
It is a good thing to have.
-Chuck Harris
satbeginner wrote:
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Hi all,
As an addition to my collection I recently got a 2465 that had the rubber/plastic ribbed pad as well.
The cut-out in the material to me makes it a TekTronix original, especially because it keeps the ventilation holes exactly free.
It either serves as extra protection for the bottom, and by doing that extra protection for the interior electronics,
it also can be a saveguard that prevents the ventilation holes to be blocked when stacking devices, as people often do.
Some pictures here: /g/TekScopes/album?id=89635
Un saludo,
Leo
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Re: What's the rubber pad under the 2465?
Hi all, As an addition to my collection I recently got a 2465 that had the rubber/plastic ribbed pad as well. The cut-out in the material to me makes it a TekTronix original, especially because it keeps the ventilation holes exactly free. It either serves as extra protection for the bottom, and by doing that extra protection for the interior electronics, it also can be a saveguard that prevents the ventilation holes to be blocked when stacking devices, as people often do. Some pictures here: /g/TekScopes/album?id=89635Un saludo, Leo
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Re: Absurdly simple way to get contact cleaner into some Tek pots
Those are called Mod-pots, for modular pots.
At one time you could get a kit to assemble these as you needed, for prototyping and repair.
Now the kits are no longer available and the pots are assembled with rivets instead of screws.
When I see these at hamfests and they are assembled with screws, I get them to use for replacement parts.
Glenn
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Show quoted text
On 4/15/2019 9:57 PM, Dennis Tillman W7PF wrote: For years I've struggled with what to do about noisy pots. Until now the
best solution I have come up with is to remove the knob and drip contact
cleaner down the shaft. It only works a small percentage of the time. And
I'm not sure it can even work on ganged pots at all. Plus it is quite messy
since it is almost impossible to control the burst of contact cleaner that
comes out.
Faced with the same problem once again an idea struck me while I was staring
at the back side of one of the very common black square pots (single or
ganged). The ones I'm referring to have four tiny screws holding them
together from back to front.
SOLUTION: Remove one of the screws and squirt the contact cleaner into the
hole. All four of the screws screw into a metal plate at the front of the
pot. So the screw hole passes through every section of the pot (or multiple
pots regardless of how many there are.
It's too early yet to tell how effective this is. I only just discovered it.
Dennis Tillman W7PF
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
|
Absurdly simple way to get contact cleaner into some Tek pots
For years I've struggled with what to do about noisy pots. Until now the
best solution I have come up with is to remove the knob and drip contact
cleaner down the shaft. It only works a small percentage of the time. And
I'm not sure it can even work on ganged pots at all. Plus it is quite messy
since it is almost impossible to control the burst of contact cleaner that
comes out.
Faced with the same problem once again an idea struck me while I was staring
at the back side of one of the very common black square pots (single or
ganged). The ones I'm referring to have four tiny screws holding them
together from back to front.
SOLUTION: Remove one of the screws and squirt the contact cleaner into the
hole. All four of the screws screw into a metal plate at the front of the
pot. So the screw hole passes through every section of the pot (or multiple
pots regardless of how many there are.
It's too early yet to tell how effective this is. I only just discovered it.
Dennis Tillman W7PF
|
Re: 475A : excessive jitter on delayed sweep
Hi Alberto:
What you see on the display is probably correct.? With your scope cold, press the A push button and turn the A TIME/DIV knob such that two or more cycles are shown.? Rotate the B TIME/DIV control two or three positions past the A setting and press the A INTEN push button.? Adjust the intensity to show the highlighted portion of the A trace, rotate the DELAY TIME POSITION (DTP) control and watch the intensified portion move.? Using the DTP control position the starting portion of the highlighted A trace right on the rising edge, now press the ALT push button, if all is working OK you should see the A trace start then continue at the rising edge of the A trace but at the B rate.? Now press the B DEL'YD button, you should see the portion of the highlighted A trace swept at the B rate, you can move the display using the DTP control.
As to the 'hot jitters', with the scope hot, carefully measure each power supply with a good DC VOM, if you see no variation use another known good scope to view the various supplies, if you don't have another scope switch the VOM to AC and, observing polarity, connect a 10uF, 200VDC cap in series with the positive lead of the VOM, you are looking for low frequency variations in the supplies and the cap is used to block the DC component.? Once you find a supply that is varying the VOM reading, troubleshoot it and continue.? I have found that the 741 op-amp IC in the power supply is frequently at fault, a cheap fix!
Good luck!
Reed Dickinson
press the
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Show quoted text
On 4/15/2019 3:06 PM, Alberto I2PHD wrote: I fixed my 475A by replacing five tantalum caps with quality electrolytics. So far so good.
But now a new problem has surfaced. Let's see if I am able to explain it correctly, with the aid of a couple photos...
I send a 1 kHz square wave signal to the 'scope, set the A sweep to 50 us/div, triggering on the negative slope of the square signal.
Doing so, I see on the screen only the lower half of the cycle (50 us/div * 10 div = 500 us, half cycle).
Then I set the B sweep at 1 us/div, "Start after the delay" (important...)
Pressing "A intensified" I see this, which is what is to be expected :
Now I press "B delayed", and what I obtain is this, BUT ONLY AFTER A COLD START OF THE 'SCOPE :
As long as the 'scope is cold, the image is very stable. After about ten minutes, when the 'scope has had time to warm up, the display is jittering badly, going left and right, even beyond the borders of the screen...
It is clearly a problem related to temperature... Has anybody words of wisdom about which components could cause, when warning up, this problem ?
TIA
Alberto
|
475A : excessive jitter on delayed sweep
I fixed my 475A by replacing five tantalum caps with quality electrolytics. So far so good.
But now a new problem has surfaced. Let's see if I am able to explain it correctly, with the aid of a couple photos...
I send a 1 kHz square wave signal to the 'scope, set the A sweep to 50 us/div, triggering on the negative slope of the square signal.
Doing so, I see on the screen only the lower half of the cycle (50 us/div * 10 div = 500 us, half cycle).
Then I set the B sweep at 1 us/div, "Start after the delay" (important...)
Pressing "A intensified" I see this, which is what is to be expected :
Now I press "B delayed", and what I obtain is this, BUT ONLY AFTER A COLD START OF THE 'SCOPE :
As long as the 'scope is cold, the image is very stable. After about ten minutes, when the 'scope has had time to warm up, the display is jittering badly, going left and right, even beyond the borders of the screen...
It is clearly a problem related to temperature... Has anybody words of wisdom about which components could cause, when warning up, this problem ?
TIA
Alberto
--
/*73 Alberto I2PHD*
Credo Ut Intelligam/
|
Re: More Complete List of Concept Series and Measurements Concepts Books
The MediaWiki software shows broken links in red by design - one can deliberately insert links to pages or files that should be there even if they are not yet.
There are also system functions to list "wanted pages/files" sorted by number of references pointing to each.
The red links on the manuals list are simply there because we know the manual part number and its title, but don't have a file yet.
Peter
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Re: More Complete List of Concept Series and Measurements Concepts Books
PS - Someone asked if I have a PDF copy of "Typical Oscilloscope Circuitry".
I was sure that I did, but after a rather exhaustive search, I cannot find it. I am going to see if it is on the scribd website.
DaveD
toggle quoted message
Show quoted text
On 4/15/2019 1:49 PM, Dave Daniel via Groups.Io wrote: Dennis,
If he is referring to my post, then the site is the
site cited earlier in this thread. My complete (original) post had some other observations in it beside my question regarding the site's owner.
DaveD
On 4/14/2019 7:08 PM, Dennis Tillman W7PF wrote:
Hi Roy,
What site is being referred to?
It makes it much easier if we don't have to guess what your reply refers to.
By now there have been at least 50+ posts on this topic.
PLEASE include some context so we understand which of the 50+ posts your reply relates to.
So far I have not had problems logging into the TekWiki links mentioned and the Czech web site so what site has the login requirement?
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy
Thistle
Sent: Sunday, April 14, 2019 10:37 AM
Subject: Re: [TekScopes] More Complete List of Concept Series and
Measurements Concepts Books
On Sat, Apr 13, 2019 at 09:25 AM, Dave Daniel wrote:
Does anyone know who the owner of this site is?
Hi:
I've seen that question asked on the forum before. IMHO, if people keep
asking, the site will soon disappear... like others, that were once up,
have.
Regards.
|
Re: 7S12 with S-4 and S-53 troubleshooting
Hi Nenad, One more perhaps superfluous question. In your first post you say
I connected the same signal (10MHz <1Vpp) to both heads inputs just for
test (let's just ignore this blasphemy for now since both inputs are 50Ohm,
The heads have different connectors, SMA and BNC, and your signal generator perhaps one of these. You need a power divider or a splitter or a T and at least an adapter to from one type connector to another. All these things could introduce faults. Are you 100% sure that the sine wave signal arrives "inside" the S-4? Albert
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Re: More Complete List of Concept Series and Measurements Concepts Books
Dennis,
If he is referring to my post, then the site is the
site cited earlier in this thread. My complete (original) post had some other observations in it beside my question regarding the site's owner.
DaveD
toggle quoted message
Show quoted text
On 4/14/2019 7:08 PM, Dennis Tillman W7PF wrote: Hi Roy,
What site is being referred to?
It makes it much easier if we don't have to guess what your reply refers to.
By now there have been at least 50+ posts on this topic.
PLEASE include some context so we understand which of the 50+ posts your reply relates to.
So far I have not had problems logging into the TekWiki links mentioned and the Czech web site so what site has the login requirement?
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy
Thistle
Sent: Sunday, April 14, 2019 10:37 AM
Subject: Re: [TekScopes] More Complete List of Concept Series and
Measurements Concepts Books
On Sat, Apr 13, 2019 at 09:25 AM, Dave Daniel wrote:
Does anyone know who the owner of this site is?
Hi:
I've seen that question asked on the forum before. IMHO, if people keep
asking, the site will soon disappear... like others, that were once up,
have.
Regards.
|
Re: Tektronix P6202 FET voltage probe tip problem
I liked the idea of using inertia so I made a mouse trap into a pin debris remover. The P6202 socket is going into the hole I am drilling /g/TekScopes/photo/89499/2?p=Created,,,20,2,0,0 I drilled a much larger hole underneath so the debris had somewhere to go /g/TekScopes/photo/89499/1?p=Created,,,20,2,0,0 The socket pin is temporarily soldered to the PCB at O. Many snaps of the trap later, about two dozen, until it started to fall apart. I thought something had come out of the hole but a 0.020 wire still does not enter the socket hole at all. /g/TekScopes/photo/89499/0?p=Created,,,20,2,0,0 I don't know if I said this but Keystone makes similar sockets. 0.032" seems to be a popular size.
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Re: Tektronix P6202 FET voltage probe tip problem
I've added another pic of the tip with the socket now removed. /g/TekScopes/photo/89499/0?p=Created,,,20,2,0,0 Keystone makes similar sockets. 0.032" seems to be a popular size. Now that i have the socket off the board there is less hazard to the probe while I work on the socket. I will definitely need to jig it to solder it back. The teflon washer just pops off the smaller end of the socket. Thanks to everyone for interest and support! :) George
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Craigslist- Baltimore MD area Tek 577 for sale
I have no affiliation with the seller:
Wish I had room (and the $) to add it to my shack...
Mike Dinolfo N4MWP
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Re: Tektronix P6202 FET voltage probe tip problem
Thanks for the link Siggi.
George-
looks like the tip (point) base was left in the hole? Is the tip rear intact when it was removed? or did probe arrive in this condition?
I see a few options,? removal of material most likely will mean removal of the socket then work in a lathe/mill,? possible replacement with a new/modified/socket from a IC socket, I would have to have it in hand to see what else comes to mind, but it looks doable. just time consuming.
?hmmm i wonder if a water jet might be used??? Is the "broken wire" "loose" in the hole???
oh yes- resistors a cap then directly to the FET, look at the schematics....definite removal to prevent damage to the FET(s)
¸é±ð²Ô¨¦±ð
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Show quoted text
On 2019-04-15 6:52 a.m., Siggi wrote: Here's a link to the album: /g/TekScopes/album?id=89499.
On Mon, Apr 15, 2019 at 9:19 AM GeorgeP <george@...> wrote:
I have added three more close ups of the tip socket in the Photos folder
here at TekScopes named "Tektronix P6202 FET voltage probe tip problem "
Someone asked me in an email if I could put a link. I wish I knew how. I
don't think I can link to a pic that I've posted. I am new again to
Tekscopes. I don't know how. But you will find almost 20 good pics of a
P6202 Fet probe that will hopefully help me or someone else in future deal
with a damaged tip socket.
The socket seems to have a U tab that straddles the end of the PCB. It is
probably hard soldered in a jig. Likely the socket is closed at the bottom
to prevent wicking. The small teflon? washer is slightly loose on the body
of the socket but doesn't come off. I can see what I think is the FET and a
couple of surface mount resistors? one of which is adjacent to the solder
pad for the tip socket.
Pics show an object, probably a broken off piece of wire, round in a
square hole. Too small and too deep to grab.
I don't know how to deal with this.
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Re: Tektronix P6202 FET voltage probe tip problem
And for the advice about adding links!
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Re: Tektronix P6202 FET voltage probe tip problem
Wow! Good ideas! Thank you for the thoughts Harvey! Will report back.
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Re: Tektronix P6202 FET voltage probe tip problem
On Mon, 15 Apr 2019 06:19:18 -0700, you wrote: I have added three more close ups of the tip socket in the Photos folder here at TekScopes named "Tektronix P6202 FET voltage probe tip problem "
Someone asked me in an email if I could put a link. I wish I knew how. I don't think I can link to a pic that I've posted. Go to the picture you've posted, open it in your browser. In the address field of the browser window (which changes to where you are), select and highlight the complete address. Go back to your email and paste that in. That's one way to do it. I am new again to Tekscopes. I don't know how. But you will find almost 20 good pics of a P6202 Fet probe that will hopefully help me or someone else in future deal with a damaged tip socket.
The socket seems to have a U tab that straddles the end of the PCB. It is probably hard soldered in a jig. Likely the socket is closed at the bottom to prevent wicking. These sockets are indeed closed at the bottom. They're meant to be put into a PC board and soldered in to lower the profile of whatever chip (or part) is inserted into them. The small teflon? washer is slightly loose on the body of the socket but doesn't come off. I can see what I think is the FET and a couple of surface mount resistors? one of which is adjacent to the solder pad for the tip socket. The teflon washer is likely meant to keep the probe tip from grounding out against the outer probe body.
Pics show an object, probably a broken off piece of wire, round in a square hole. Too small and too deep to grab.
I don't know how to deal with this.
One would be to replace the socket. Another would be to remove the socket, go to a room without much in it, grasp the socket firmly (but gently) with pliers, and then bang the pliers sharply against a block of wood. If the obstruction goes away, you're lucky. A question is to ask if you are sure that the socket is obstructed. It has to have a set of contacts in it. Take a sewing needle or pin of the right diameter (I measured 0.030 on the tip of my P6202), and see if it is obstructed. The needle should bottom out gently. if a simulated probe tip fits in, there may not be an obstruction. I'm rather puzzled how something could break inside the socket. I've seen many broken tips, but they all die at the junction of the external tip and the replaceable body. If you can't clear it out, and you're willing to take a chance, I have a few sockets that a probe tip will slide into. You'd have to be willing to remove the socket and replace it, though. Harvey
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Re: 7S12 with S-4 and S-53 troubleshooting
Hi Nenad,
I did, I uploaded a photo here:
/g/TekScopes/photo/89504/0?p=Created,,,20,2,0,0
this was taken with SCAN at approx. 21h position, so that "Morse code" could be seen.
Your photo reminded me of a modification I made in my 7S12. See here and surrounding messages: /g/TekScopes/message/96331I'm not sure your "morse code" problem is related to it and also not whether it's related to the unit not showing waveforms. W.r.t. sensitivity for DC input (did you try?) I forgot that the setting of S901 "Correction Memory Switch", see page 2-5, is important. For now the best way is to set the switch in the rear (OFF) position (as long as you don't have a pulse generator head). Here is one more attempt to show that the preamplifier responds to the strobe pulses. With a DMM attached to the front panel Vertical Out connector you can see that Memory is slowly drifting when no strobe pulses are generated. You can set the S-53 for free running when Level is roughly midway and Stability cw, and stop and start free running by slight rotation of the Level knob. You don't need any signal for this and you can try it at different Offset levels. During free running the DMM will reflect the vertical position of the visible trace, and will listen to variations in Offset. When you turn off free running, the trace gets blanked but the DMM still shows the trace position. You will see the DMM reading slowly drifting away in some direction. When you turn free running on again, the DMM reading will immediately jump back to the normal value. The trace should reappear immediately at the previous vertical position. If you don't want to wait for drift you can change Offset while free running is off; the trace should immediately be at the new position when you turn free running on again. Albert
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Re: Tektronix P6202 FET voltage probe tip problem
toggle quoted message
Show quoted text
On Mon, Apr 15, 2019 at 9:19 AM GeorgeP <george@...> wrote: I have added three more close ups of the tip socket in the Photos folder
here at TekScopes named "Tektronix P6202 FET voltage probe tip problem "
Someone asked me in an email if I could put a link. I wish I knew how. I
don't think I can link to a pic that I've posted. I am new again to
Tekscopes. I don't know how. But you will find almost 20 good pics of a
P6202 Fet probe that will hopefully help me or someone else in future deal
with a damaged tip socket.
The socket seems to have a U tab that straddles the end of the PCB. It is
probably hard soldered in a jig. Likely the socket is closed at the bottom
to prevent wicking. The small teflon? washer is slightly loose on the body
of the socket but doesn't come off. I can see what I think is the FET and a
couple of surface mount resistors? one of which is adjacent to the solder
pad for the tip socket.
Pics show an object, probably a broken off piece of wire, round in a
square hole. Too small and too deep to grab.
I don't know how to deal with this.
|
Re: Tektronix P6202 FET voltage probe tip problem
I have added three more close ups of the tip socket in the Photos folder here at TekScopes named "Tektronix P6202 FET voltage probe tip problem "
Someone asked me in an email if I could put a link. I wish I knew how. I don't think I can link to a pic that I've posted. I am new again to Tekscopes. I don't know how. But you will find almost 20 good pics of a P6202 Fet probe that will hopefully help me or someone else in future deal with a damaged tip socket.
The socket seems to have a U tab that straddles the end of the PCB. It is probably hard soldered in a jig. Likely the socket is closed at the bottom to prevent wicking. The small teflon? washer is slightly loose on the body of the socket but doesn't come off. I can see what I think is the FET and a couple of surface mount resistors? one of which is adjacent to the solder pad for the tip socket.
Pics show an object, probably a broken off piece of wire, round in a square hole. Too small and too deep to grab.
I don't know how to deal with this.
|
satbeginner
Alberto I2PHD
GeorgeP
Mike Dinolfo