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I remember seeing in the distant past, a catalog picture of a pot/contact cleaner which threaded onto the pot threaded bushing. I guess you would then put in the cleaner/lube, and push a plunger to force the cleaner into the pot.

John

Hi ...,
I just sent you the TDS600B software. This may work for you. I am not aware of the availability of the TDS600C software.

Raymond

I do the same thing for repairing old electronics in general. If it is a sealed pot, unseal it. I just carefully drill a hole like you do Richard.

Hi John,
There's nothing wrong with your 7B71. If anything, I am surprised at the speed of unblanking that I see, especially at 100 ns/div. Unblanking is when the beam, which has been suppressed during its return from the far right of the screen to the starting position at the left, regains its brightness (Z-axis control). Normally, it takes a time that's enough to make the brightness increase visibly for a few (minor) divisions at this kind of horizontal speed.
Back to your issue: The horizontal starting position on the screen is never an indication of time with regard to the trigger moment, especially at different higher-speed sec/div. settings. The trigger position moves with the div/sec. setting - and with the horizontal position setting knob.
As a final remark, the edge speed (step) of your vertical signal is relatively slow, which may result in a vague trigger "moment".

Raymond

Hi folks,

I have a Tektronix TDS654C that is in need of calibration, as I had to replace a couple of attenuators on the unit. I believe the previous owner must have severely overloaded a couple of the channels, because after the attenuator replacement the unit now works fine. However, a full calibration is in order.

I have everything I need now in order to do the calibration except the TDS600C Field Adjustment Software. I have found the TDS700A, 700C, and 700D, and 500 software on the web, but no luck with the TDS600C. Does anyone have a copy of it or know it is on the web? I've checked the Tek wiki site and the K04bb site as well as others and no luck.

I appreciate the help.

Thanks

I've got a 7B71 that has problems when in the .05us, and .02us positions.
The trace starts at a level corresponding to the trigger level as the trigger level knob is turned.
Triggering is in normal mode. Horizontal position is set so that slower sweeps start at 1 division.

I already ran isopropyl soaked rag paper under some of the contacts of the 29 contact drum operated switch.
Many are very inaccessible. The switch numbered positions of the schematic are not identified on the pcb layout drawing.
So, I suppose the only way to figure which is which is trace layout paths to resistors and capacitors of the timing.

These photos show the problem -- the trace starts early some of the time, and starts randomly in time some of the time:

good (1us/div)
good (500ns/div)
early (200ns/div)
early (100ns/div)
random (50ns/div)
good (20ns/div)

The good traces all start at 1 division, just like the slower sweeps which were used to set Horiz pos at 1 div from left.
Since "going back in time" is probably not a function of the timing R's and C's,
I'm thinking the triggering is where to look. Any other ideas?

would be interesting to submerge a "sealed" pot in a liquid and see if the pot eventually fills up, just as an experiment to see just how well these sealed pots are sealed.

Some time ago I had to submerge an unobtainium unsealed pot into a beaker of IPA in order to free the shaft's rotation. It took a couple of days of immersion to free up the shaft. I'm guessing that a "sealed" pot would take much, much longer to absorb the fluid.

DaveD

My foolproof method is to drill
a small hole on the top side at
the rear. Pump in De-Oxit Fader
Lube and seal the hole with some
black tape.

73, Dick, W1KSZ

On Tue, Apr 16, 2019 at 10:45 AM Terry Gray via Groups.Io <tlgray42=
yahoo.com@groups.io> wrote:

I also have restored 100's of "sealed"? noisy controls by pointing the
control shaft straight up vertically, wrapping something around the bottom
of the control to catch the excess contact CLEANER/LUBE, spray around the
base of the shaft where it goes into the control, and "pump" the shaft up
and down and give it time to "pump" the contact cleaner/lube down into the
control---remember patience is a virtue. If at first it doesn't seem to be
getting the spray down the shaft, make a dam" just below the point where
the shaft enters into the control and try spraying a little additional
cleaner/lube into that area keeping it saturated and at the same time
periodically "pumping' the shaft up and down to allow the cleaner/lube to
migrate along with capillary action down the shaft. Allow the potentiometer
shaft to remain pointed up vertically. Sometimes it can take overnight or
longer to get the cleaner/lube down into the control but I have found over
the last 50-60 years that it very, very rarely fails. Just be patient and I
think this will work for you, even for the difficult ones. I remember
setting upright on their backs some of the big monster stereos and doing
just that, especially when the potentiometer access was not readily
accessible even with the long extended flexible tubing that sometimes came
with the contact cleaner/lube or that were also available at the time. I
also remember running into some well sealed potentiometers and TV tuners
that we had to drill a small access hole into/through the metal or plastic
housing to get the cleaner/lube inside to do its job. Just be very careful
to not drill into the tuner or control doing any internal damage. I
remember disassembling throw-away pots and tuners to learn where to drill
the holes to prevent any internal damage and you could then seal the hole
up with solder or glue when you completed the cleaning/lube process. One
additional point, DO NOT use a contact cleaner with no lubricating agent in
its ingredients. Many years ago I attended a Channel Master seminar on
their contact cleaners and tuner (and switch) cleaner/lubes. The company
representative showed us under a fairly high-powered microscope a video of
what happens when you spray a contact cleaner (with no lube) on the old TV
tuner switch contacts You completely wash away all lubrication from the
individual contact points and he showed us under the microscope what
happens when you rotate the switch thru the washed contacts. It scrapes the
plating off the contacts and now being unplated in that area it is oxidizes
and you end up with intermittent high resistance contacts down the
line(with time) that play havoc with your circuit. You think that you are
"fixing" the intermittent switch contact(s) (or the intermittent internal
potentiometer wiper problem) but in reality you are totally ruining (for
the future) whatever you are so-called restoring by using a non-lubricated
spray. I wish the video that the Channel Master rep showed us was still
available>>>>it looked like a chisel scraping the plating off the contact
under the high-magnification microscope when all the lubrication had been
previously "cleaned" off the contact areas. He said DO NOT EVER use a
contact cleaner that has no lubrication in it or at least follow up the
"cleaning" process by spraying or adding some additional lubrication to the
contact points. Hope this is helpful information to some of you, it sure
was for me.
On Tuesday, April 16, 2019, 9:51:07 AM CDT, Bob Koller via Groups.Io
<testtech@...> wrote:

Try it sometime, I have literally done hundreds this way. Some last week..

I also have restored 100's of "sealed"? noisy controls by pointing the control shaft straight up vertically, wrapping something around the bottom of the control to catch the excess contact CLEANER/LUBE, spray around the base of the shaft where it goes into the control, and "pump" the shaft up and down and give it time to "pump" the contact cleaner/lube down into the control---remember patience is a virtue.? If at first it doesn't seem to be getting the spray down the shaft, make a dam" just below the point where the shaft enters into the control and try spraying a little additional cleaner/lube into that area keeping it saturated and at the same time periodically "pumping' the shaft up and down to allow the cleaner/lube to migrate along with capillary action down the shaft. Allow the potentiometer shaft to remain pointed up vertically. Sometimes it can take overnight or longer to get the cleaner/lube down into the control but I have found over the last 50-60 years that it very, very rarely fails. Just be patient and I think this will work for you, even for the difficult ones. I remember setting upright on their backs some of the big monster stereos and doing just that, especially when the potentiometer access was not readily accessible even with the long extended flexible tubing that sometimes came with the contact cleaner/lube or that were also available at the time.?? ?I also remember running into some well sealed potentiometers and TV tuners that we had to drill a small access hole into/through the metal or plastic housing to get the cleaner/lube inside to do its job. Just be very careful to not drill into the tuner or control doing any internal damage. I remember disassembling throw-away pots and tuners to learn where to drill the holes to prevent any internal damage and you could then seal the hole up with solder or glue when you completed the cleaning/lube process.? ?One additional point, DO NOT use a contact cleaner with no lubricating agent in its ingredients. Many years ago I attended a Channel Master seminar on their contact cleaners and tuner (and switch) cleaner/lubes. The company representative showed us under a fairly high-powered microscope a video of what happens when you spray a contact cleaner (with no lube) on the old TV tuner switch contacts? You completely wash away all lubrication from the individual contact points and he showed us under the microscope what happens when you rotate the switch thru the washed contacts. It scrapes the plating off the contacts and now being unplated in that area it is oxidizes and you end up with intermittent high resistance contacts down the line(with time) that play havoc with your circuit. You think that you are "fixing" the intermittent switch contact(s) (or the intermittent internal potentiometer wiper problem) but in reality you are totally ruining (for the future) whatever you are so-called restoring by using a non-lubricated spray.? ?I wish the video that the Channel Master rep showed us was still available>>>>it looked like a chisel scraping the plating off the contact under the high-magnification microscope when all the lubrication had been previously "cleaned" off the contact areas. He said DO NOT EVER use a contact cleaner that has no lubrication in it or at least follow up the "cleaning" process by spraying or adding some additional lubrication to the contact points.? ?Hope this is helpful information to some of you, it sure was for me.

. My Solution?

Please don't cringe too much. I use an exacto and slowly and carefully
scrap and carve away at a small section of the plastic switch housing until
I have a small hole in it. I spray the contact cleaner in it and rotate
the switch. It then works perfect and the instrument is usable again.

=============================================================================

No need to cringe. That solution has been around since the 1950's +/- with the erratic strip tuners in TV receivers.

Insert the hose into one of the various holes of the tuner and apply the product while exercising the tuner knob. WD-40 was used for that fix.

Tektronix included a can of WD-40 in their maintenance kit for pots and switches in that general time frame.

Rolynn
Tek Bvtn & Sunset 1966-1971

On an old piece of crt based UT equipment (none-o-scope) that I have to fix
occasionally, had a sealed rotary switch that gets flashy to the point
where the instrument in non-usable, They are soldered to a front panel PCB
and then through the panel, along with about ten other controls and of
course short and fragile wiring harnesses. It is a huge amount of work to
get that PCB off, plus if you do, the switch it sealed and made of
unobtainium. Luckily, the switch that goes very flashy and makes the
instrument non-usable is on the outside edge of the PCB. My Solution?
Please don't cringe too much. I use an exacto and slowly and carefully
scrap and carve away at a small section of the plastic switch housing until
I have a small hole in it. I spray the contact cleaner in it and rotate
the switch. It then works perfect and the instrument is usable again.

On Mon, Apr 15, 2019 at 9:57 PM Dennis Tillman W7PF <dennis@...>
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

On 16 Apr 2019, at 16:43, redarlington <rdarlington@...> wrote:

I backed it up so it won't go away forever.

I have too.

Though I have the capability and capacity to do so, I’m rather uncomfortable about making it publicly available without assurance that all the material is legally redistributable.

Retained for context:

What I don't have is a place
to dump it online with enough storage for even a quarter of it.

Downloaded: 37670 files, 136G in 14h 2m 14s (2.76 MB/s)

-Bob

On Sun, Apr 14, 2019 at 11:37 AM Roy Thistle <roy.thistle@... <mailto:roy.thistle@...>>
wrote:

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.

I have a spare 500GB disk I could add to my server for that data. The next trick is modifying my website to serve it back to the masses. The rsync from the main server should be easy enough to implement for keeping the archive up to date. Our pipe isn't terribly big 100dwn/20up but it is online 24/7

steve

I backed it up so it won't go away forever. What I don't have is a place
to dump it online with enough storage for even a quarter of it.

Downloaded: 37670 files, 136G in 14h 2m 14s (2.76 MB/s)

-Bob

On Sun, Apr 14, 2019 at 11:37 AM Roy Thistle <roy.thistle@...>
wrote:

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.

Try it sometime, I have literally done hundreds this way. Some last week..

An easier way with the modpot is to apply a drop on the red "square" on one side. It flows directly into the the track, sort of... Sometimes two applications are required.

Unless you squirt the contact cleaner in under pressure, I doubt that much
of it will find its way to the resistive element. What would be better is
to slightly loosen the other 3 screws and again squirt the cleaner in under
pressure. Some will find its way to the outside, so be sure to wrap the
potentiometer with tissue paper to block the vapor's path.

Gary

On Mon, Apr 15, 2019 at 6:57 PM Dennis Tillman W7PF <dennis@...>
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

--
Gary Robert Bosworth
grbosworth@...
Tel: 310-317-2247

I saw the explanation for the rubber pad, I think on the VintageTek site, from an engineer on the 2465 project. The reason the pad was included was, there were incidents of the input attenuator ceramic substrate being broken if the instrument was impacted on the case bottom rather than the feet. Something about the case seam transferring the force into the substrate. As I recall the case seam was also moved off center.
I have replaced a few broken attenuators, but didn't understand the mechanism.
If I can find the info I will ad it.

On 2019-04-16 1:08, Reed Dickinson wrote:

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.

Hi Reed,

?? thanks for your answer. Yes, that is exactly what I did to obtain what is shown in my photo Nr. 2.
All normal and all well understood.? But what I expected to see was a stable rising edge of the signal, as in the photo, taken with the 'scope cold, just switched on.
The problem is that when the instruments warms up, that rising edge is no more stable, the trace moves left and right, in a random fashion.
Clearly a problem related to the warming of the 'scope...

I will check, as you suggested, the voltages. There is a suspect tantalum capacitor, which I did not replace, namely C933, which is in the path that brings working voltage to the Delay Time Position control.... just as good measure, I will replace that also...

Thanks and regards

Alberto

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: