Date   

Re: Tektronix RAMS (Surplus) Store - Odd hours?

Magic_Smoke
 

Bringing this thread back from the dead, does anyone know if RAMS has (or is planning to be) reopened post-COVID? I miss it!


Re: 2445b shelf vents for bottom air intakes - should I?

Keith
 

Hi Leo and others,

Thanks for chiming in;

re: U800, Yes, definitely had that discussion in my head. I've heard it both ways on the U800 chip - sink and no sink. I know they get fairly warm, or at least mine does, because I checked it several years ago. At the time it seemed like a good candidate for a little heat sink, but I'm only guessing. I reckon I should relax and trust Tek on the airflow design.

re: "holes could make it worse". Yeah, I have some experience loading racks and racks of hot gear in a variety of settings and so I'm quite familiar with what you describe. (i.e. "chimney effect") Although I didn't build such a problem into my setup, I think I may just let the 2445b cooling ride as is for now while I work on replacing the nasty burned up RIFA caps and cleaning up the mess I know it left inside. That's a "for sure" problem.

In any case, after today I have a lot more things to fix on my bench now. The 2445b stink bomb, and replacing that oil-filled cap that gave up the ghost in my Sola constant voltage transformer today. Then about ten other real work projects that need my attention.

Oh well, that's why I have a fancy new electronics bench! :-)

Keith


Tek 2230 Repair and Maintenance

Charlie
 

Greetings,

I hope this message finds everyone well. I am calling on anyone who would like to offer some tips and/ or assistance. I am a new(er) member and thus far I have been following along and using the search function from time to time to get some direction on my little project. It has been a little slow going since there is so much information on here to sift through, but I am hoping someone can give me a kick in the right direction. I already know I will greatly appreciate it. Please excuse any mistakes and simplifications. I am not a professional electrical engineer, but a hobbyist with a fair amount of formal EE education.

Here is a little background...I purchased two of these scopes, one was supposed to be in good working order, one was for parts. The "good" scope has the GPIB option. On start up of the "good" scope I keep seeing this image on the CRT

https://photos.app.goo.gl/GwUdDxu25jh4APwZ6
A few times the unit would show the traces and I could get into the setup menus. This was unpredictable and I would say 90% of the time the scope would lock up on the screen shown above. When I was able to to see the traces and get into the menus the cursor knob was wildly erratic. From what I have read this is pretty common issue with the cursor control. Aside from these issues the scope seemed to function OK. I should note that I have not done any other testing on this scope. Currently the scope is almost completely dissembled, A1-A6 boards are still mounted to the frame.

As of now, my intentions are the following, with any questions/ comments below;

1. Replace line filtering caps (A6 caps and A1C904)

2. Replace all electrolytic caps, particularly all power supply caps

Do I need to worry about the slew of tantalums throughout the scope? Some are conformally coated, some are hermetically sealed (relatively expensive). I have put together a spreadsheet/ BOM with replacements. I will post a link if someone can double check my choices

3. Disassemble and carefully clean the dual inline continuous rotation potentiometer (A24R9412)

I haven't found any replacements (no surprise). I plan on characterizing the operation of the pot to get an idea of its operation so I might be able to design a replacement. My question is, how do these operate to form the signal for the A11A1U6106 MUX? I have found one gentleman online (I believe he is a member of this group) who at one time made a custom replacement for these using a microcontroller an encoder and a digital potentiometer, but at this time does not plan on making another batch. He did however give some pointers on disassembling and cleaning the pot.

4. Replace the extended memory battery

I remember seeing somewhere on this forum that this battery is used to protect waveform data, not calibration data. Is this correct?

5. Startup and test the scope

Aside from what I have planned, are there any bugs I need to look for, or are there any other preventative maintancence items I should plan on doing?

Again, I truly appreciate any assistance offered. I have been very excited to get this scope back to operating condition.

Regards,

Charlie


Re: Smoke damage 7704A

Renée
 

Hi Tom-
i have had to do this numerous times on pieces of equipment involved in fire/smoke over the years- mostly 50kv and 500kv supplies. took them apart, 409 ( had an oily residue on a few)  or something that dissolves the carbon/smoke residue, scrub with brush if at all possible, hose it down, repeat as needed. finally dunk/ rinse it in IPA and blow it off, repeat couple of times .  after a good air dry like 24 hrs, then put it in an oven for several hours ( overnight) between 100 and 150 F. reassemble an have had full recovery....some of theses were really bad. in fact they were black!..you could measure the resistance across the boards!
I always worried about arcing in HV xformers but cleaning worked.... In fact i know a couple are still working just fine after 10 years.
try to avoid getting too much water/liquid in the xformers if possible and no hi pressure spray..most everything else seems to hold up ok.... now faceplates/lettering your mileage will vary- test first.
I have to rebuild the stuff anyway..so I always figured what do I have to loose?
Hope this helps
Renée

On 7/14/21 12:18 PM, Thomas Voshell wrote:
I have a 7704A that was damaged in a house fire. The scope was in a closet upstairs and everything outside of the closet was either melted or burned. There is significant smoke residue on the outside of the covers and possibly some overspray from fire hoses. I have not yet taken the covers off; no knobs frame plastics are melted on mainframe or plug-ins which look externally smoked up. (7a18, 7a26, 7b50, 7b51). I believe powering it up would be foolhardy as carbon conducts. My inclination is to completely disassemble the frame and wash with water the electronics and allow to air dry. Due to age I am worried about old plastic flat cable connectors and the acquisition to display unit connector. The CRT connector and the HVPS also worry me.

Does anyone have any suggestions/comments/insights/experience WRT this situation?

Thanks,
TomV




Re: Smoke damage 7704A

greenboxmaven
 

I have restored many items that were exposed to smoke (usually not from a building fire!), heat, water, and dirt. In all cases, a careful bath and scrub followed by a good drying out was done, and the vast majority of times, the rig worked fine. If it didn't, the cause usually had little to do with the exposure and it was bad all along. It takes patience to do a good restoration, but if you have time, it is very rewarding. In years past, I had very little money but lots of time, and by searching for items exposed to bad events, was able to have many things I could never have afforded. The learning and satisfaction were invaluable. I had an R-390 receiver and a model 28 Teletype fifty years ago for  a total of about $60.00- a great bargain in those times- because I would take the time and do the work.

   Bruce Gentry, KA2IVY

On Wed, Jul 14, 2021, 13:20 Bill (Doc) Courtright via groups.io <doxemf=
aol.com@groups.io> wrote:

Watching. I had a similar experience. Gear in closet but lots of smoke and
water damage to all most all my 5K and 7K PI's.Luckily the 7K mainframes
were not in the building. Instead my primary 5403 was soaked when the drop
ceiling fell from the water. After a year or so of setting in a warm
house I carefully powered it up and with some control and switch cleaning
has been fine. Lucky I guess. Cannot say how well calibrated it is but my
limited references indicated that it was good enough. So good luck. I
will never get around to going over the many PI's that I have as severe
Arthritis has set in and working small controls is near impossible. Bill



-----Original Message-----
From: Thomas Voshell <tvoshell@cableone.net>
To: TekScopes@groups.io
Sent: Wed, Jul 14, 2021 3:18 pm
Subject: [TekScopes] Smoke damage 7704A

I have a 7704A that was damaged in a house fire. The scope was in a
closet upstairs and everything outside of the closet was either melted or
burned. There is significant smoke residue on the outside of the covers
and possibly some overspray from fire hoses. I have not yet taken the
covers off; no knobs frame plastics are melted on mainframe or plug-ins
which look externally smoked up. (7a18, 7a26, 7b50, 7b51). I believe
powering it up would be foolhardy as carbon conducts. My inclination is to
completely disassemble the frame and wash with water the electronics and
allow to air dry. Due to age I am worried about old plastic flat cable
connectors and the acquisition to display unit connector. The CRT
connector and the HVPS also worry me.

Does anyone have any suggestions/comments/insights/experience WRT this
situation?

Thanks,
TomV












Re: Smoke damage 7704A

Gary Robert Bosworth
 

If you ever sell any of this, please warn buyers of the history.

On Wed, Jul 14, 2021, 13:20 Bill (Doc) Courtright via groups.io <doxemf=
aol.com@groups.io> wrote:

Watching. I had a similar experience. Gear in closet but lots of smoke and
water damage to all most all my 5K and 7K PI's.Luckily the 7K mainframes
were not in the building. Instead my primary 5403 was soaked when the drop
ceiling fell from the water. After a year or so of setting in a warm
house I carefully powered it up and with some control and switch cleaning
has been fine. Lucky I guess. Cannot say how well calibrated it is but my
limited references indicated that it was good enough. So good luck. I
will never get around to going over the many PI's that I have as severe
Arthritis has set in and working small controls is near impossible. Bill



-----Original Message-----
From: Thomas Voshell <tvoshell@cableone.net>
To: TekScopes@groups.io
Sent: Wed, Jul 14, 2021 3:18 pm
Subject: [TekScopes] Smoke damage 7704A

I have a 7704A that was damaged in a house fire. The scope was in a
closet upstairs and everything outside of the closet was either melted or
burned. There is significant smoke residue on the outside of the covers
and possibly some overspray from fire hoses. I have not yet taken the
covers off; no knobs frame plastics are melted on mainframe or plug-ins
which look externally smoked up. (7a18, 7a26, 7b50, 7b51). I believe
powering it up would be foolhardy as carbon conducts. My inclination is to
completely disassemble the frame and wash with water the electronics and
allow to air dry. Due to age I am worried about old plastic flat cable
connectors and the acquisition to display unit connector. The CRT
connector and the HVPS also worry me.

Does anyone have any suggestions/comments/insights/experience WRT this
situation?

Thanks,
TomV











Re: Smoke damage 7704A

Bill (Doc) Courtright
 

Watching. I had a similar experience. Gear in closet but lots of smoke and water damage to all most all my 5K and 7K PI's.Luckily the 7K mainframes were not in the building. Instead my primary 5403 was soaked when the drop ceiling fell from the water.   After a year or so of setting in a warm house I carefully powered it up and with some control and switch cleaning has been fine. Lucky I guess. Cannot say how well calibrated it is but my limited references indicated that it was good enough.   So good luck. I will never get around  to going over the many PI's that I have as severe Arthritis has set in and working small controls is near impossible.   Bill

-----Original Message-----
From: Thomas Voshell <tvoshell@cableone.net>
To: TekScopes@groups.io
Sent: Wed, Jul 14, 2021 3:18 pm
Subject: [TekScopes] Smoke damage 7704A

I have a 7704A that was damaged in a house fire.  The scope was in a closet upstairs and everything outside of the closet was either melted or burned.  There is significant smoke residue on the outside of the covers and possibly some overspray from fire hoses.  I have not yet taken the covers off; no knobs frame plastics are melted on mainframe or plug-ins which look externally smoked up. (7a18, 7a26, 7b50, 7b51). I believe powering it up would be foolhardy as carbon conducts. My inclination is to completely disassemble the frame and wash with water the electronics and allow to air dry.  Due to age I am worried about old plastic flat cable connectors and the acquisition to display unit connector.  The CRT connector and the HVPS also worry me.

Does anyone have any suggestions/comments/insights/experience WRT this situation?

Thanks,
TomV


Re: What was the first oscilloscope to have cursors?

Brad Thompson
 

ken chalfant wrote on 7/14/2021 2:34 PM:

That’s it - (567/6R1)!
Hello--

Did you mean "what was the first oscilloscope to have cursers"?

My vote would go to the Fairchild/Dumont 766H....

73--

Brad  AA1IP


Re: explosion mystery on my 7104

Gary Robert Bosworth
 

Any cap that smoked must be replaced. Capacitors are supposed to take a
gulp of current and build up a fixed charge. If they conduct continuous
current, they are resistive and can eventually heat up and cause a fire.

On Wed, Jul 14, 2021, 11:32 n4buq <n4buq@knology.net> wrote:

Hi Keith,

After that cap smoked, the scope worked okay with the blown cap in it. I
did replace both line caps along with the electrolytics. Hopefully it's
cured for as long as I'll be using it.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Keith" <coolblueglow@gmail.com>
To: TekScopes@groups.io
Sent: Wednesday, July 14, 2021 12:28:43 PM
Subject: Re: [TekScopes] explosion mystery on my 7104

Hi Barry,

Curiously, my 2445b just blew the same part. unlike you, I got the smoke
and
the magnificent sonics and everything. Did you replace yours? My scope
seems
to be working fine without it, but of course this is an illusion, right?
:-)

Weird that both our 2445 series would blow their tops at around the same
time. Mine has about 20k hours on it.

Cheers,

Keith
coolblueglow










Smoke damage 7704A

Thomas Voshell
 

I have a 7704A that was damaged in a house fire. The scope was in a closet upstairs and everything outside of the closet was either melted or burned. There is significant smoke residue on the outside of the covers and possibly some overspray from fire hoses. I have not yet taken the covers off; no knobs frame plastics are melted on mainframe or plug-ins which look externally smoked up. (7a18, 7a26, 7b50, 7b51). I believe powering it up would be foolhardy as carbon conducts. My inclination is to completely disassemble the frame and wash with water the electronics and allow to air dry. Due to age I am worried about old plastic flat cable connectors and the acquisition to display unit connector. The CRT connector and the HVPS also worry me.

Does anyone have any suggestions/comments/insights/experience WRT this situation?

Thanks,
TomV


Re: 2445b shelf vents for bottom air intakes - should I?

satbeginner
 

Depending on the devices placed below the shelf holding the 2445, it even might be worse to have holes.

The holes in the bottom of the scope are there to let in air at ambient temperature, so if there is another warm device below it, the 2445 might suck in warmer air than expected, so the holes in the shelf could have an adverse effect.

That's why in telecom technology rack mount devices must be designed to have front to back cooling only, and not bottom upward cooling, to avoid one big chimney.

Just my 2 cents,

Leo


Re: What was the first oscilloscope to have cursors?

ken chalfant
 

That’s it - (567/6R1)!

I missed the previous mention.

Thanks very much.

Regards,

Ken

On 14Jul, 2021, at 11:47 AM, David Holland <david.w.holland@gmail.com> wrote:

The 567/6R1 combo previously mentioned?

https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fw140.com%2Ftekwiki%2Fwiki%2F567&;data=04%7C01%7C%7Cebb1536f9e7246d6731c08d946ef79a0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637618816619250166%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=GbmEzJt9jWuC24Vzvbmeg4ouhf9IJRW%2FgzPgBSqC1V8%3D&amp;reserved=0

David


On Wed, Jul 14, 2021 at 1:28 PM ken chalfant <kpchalfant@msn.com <mailto:kpchalfant@msn.com>> wrote:

Greetings,

I can’t prove it even looking back at my really old Tektronix catalogs -
but, when I was in HS back in the late 1960’s a professor at the local
college, what was then the Cragmor Campus in Colorado Springs, part of CU
Boulder, would let me come up to their lab and mess around with test
equipment.

They had a Tek scope that was as big (maybe bigger) than a Tek 556. It
had a large plug-in on the right hand side that, as I recall, allowed for
time measurements. It may have even been able to do amplitude. If my
memory serves me it would allow the user to place intensified dots on the
trace and it displayed the value on Nixie tubes within the plug-in.

Does anybody else remember a scope like this?

Ken


On 14Jul, 2021, at 1:09 AM, cmjones01 <chris@stumpie.com> wrote:

On Tue, Jul 13, 2021 at 8:05 PM nj902 <wb0emu@arrl.net> wrote:

Cursors as in highlighted dots (or bars) that can be moved along the
trace with a corresponding method of determining time and voltage..

A second part of the question (if the answer is different) - which was
the first Tektronix scope to have cursors.

Cursor voltage measurement on a Tek scope would have been possible in
1974, certainly. With a 7D12/M2 plugin the timebase delay settings can
be used to highlight a portion of trace for voltage measurement, and
any delayed timebase with a calibrated delay will effectively do
cursor time measurement. If you want on-screen digital readout of
delta-delayed time that comes in 1976 with the 7B85. So in the 7000
series scopes, I'd say that manually-controlled digital cursor
measurements of time and voltage were possible together for the first
time in 1976.

Chris











Re: explosion mystery on my 7104

n4buq
 

Hi Keith,

After that cap smoked, the scope worked okay with the blown cap in it. I did replace both line caps along with the electrolytics. Hopefully it's cured for as long as I'll be using it.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Keith" <coolblueglow@gmail.com>
To: TekScopes@groups.io
Sent: Wednesday, July 14, 2021 12:28:43 PM
Subject: Re: [TekScopes] explosion mystery on my 7104

Hi Barry,

Curiously, my 2445b just blew the same part. unlike you, I got the smoke and
the magnificent sonics and everything. Did you replace yours? My scope seems
to be working fine without it, but of course this is an illusion, right? :-)

Weird that both our 2445 series would blow their tops at around the same
time. Mine has about 20k hours on it.

Cheers,

Keith
coolblueglow






Re: 2445b shelf vents for bottom air intakes - should I?

Michael W. Lynch
 

RIFA Caps

--
Michael Lynch
Dardanelle, AR


Re: 2445b shelf vents for bottom air intakes - should I?

Tom Gardner
 

When my delayed action smoke generator fired, it destroyed a series
resistor, a 1cm diameter patch of prepreg, and deposited pots of
carbon on the PCB and the exhaust fan.

At the very least you should inspect the area to see if you need to
remove a carbon deposit. Replacing all the RIFAs and the Al
electrolytic isn't difficult, but replace one at a time since there is
a discrepancy on some 24x5x.

On 14/07/2021, Keith <coolblueglow@gmail.com> wrote:
Thanks Jose,

Yes, that's the one I was worrying about. I'm going to cut the holes and add
a small fan too.

Curiously, I just put the 2445b up on the finished shelf and fired it up.
(no holes yet)

A few minutes after I fired it up, she made a terrible sound and magic smoke
came out.

I believe it was simply the Line RF filter module failing, which I've heard
others describe here on the forum. Apparently, it gives this rather
magnificent and stinky display of failure - and the scope keeps on working,
though without (I presume) RF filtering on the AC line in.

Just a good reminder that these devices are not getting any younger, and
neither am I!

Cheers

Keith
coolblueglow






Re: What was the first oscilloscope to have cursors?

Dave Voorhis
 

On 14 Jul 2021, at 18:28, ken chalfant <kpchalfant@msn.com> wrote:


Greetings,

I can’t prove it even looking back at my really old Tektronix catalogs - but, when I was in HS back in the late 1960’s a professor at the local college, what was then the Cragmor Campus in Colorado Springs, part of CU Boulder, would let me come up to their lab and mess around with test equipment.

They had a Tek scope that was as big (maybe bigger) than a Tek 556. It had a large plug-in on the right hand side that, as I recall, allowed for time measurements. It may have even been able to do amplitude. If my memory serves me it would allow the user to place intensified dots on the trace and it displayed the value on Nixie tubes within the plug-in.

Does anybody else remember a scope like this?
Mentioned earlier in this thread, it’s probably a 6R1 plugin for the 567 oscilloscope.

In other words, one of these? https://w140.com/tekwiki/wiki/6R1

In one of these? https://w140.com/tekwiki/wiki/567


Re: What was the first oscilloscope to have cursors?

David Holland
 

The 567/6R1 combo previously mentioned?

https://w140.com/tekwiki/wiki/567

David

On Wed, Jul 14, 2021 at 1:28 PM ken chalfant <kpchalfant@msn.com> wrote:

Greetings,

I can’t prove it even looking back at my really old Tektronix catalogs -
but, when I was in HS back in the late 1960’s a professor at the local
college, what was then the Cragmor Campus in Colorado Springs, part of CU
Boulder, would let me come up to their lab and mess around with test
equipment.

They had a Tek scope that was as big (maybe bigger) than a Tek 556. It
had a large plug-in on the right hand side that, as I recall, allowed for
time measurements. It may have even been able to do amplitude. If my
memory serves me it would allow the user to place intensified dots on the
trace and it displayed the value on Nixie tubes within the plug-in.

Does anybody else remember a scope like this?

Ken


On 14Jul, 2021, at 1:09 AM, cmjones01 <chris@stumpie.com> wrote:

On Tue, Jul 13, 2021 at 8:05 PM nj902 <wb0emu@arrl.net> wrote:

Cursors as in highlighted dots (or bars) that can be moved along the
trace with a corresponding method of determining time and voltage..

A second part of the question (if the answer is different) - which was
the first Tektronix scope to have cursors.

Cursor voltage measurement on a Tek scope would have been possible in
1974, certainly. With a 7D12/M2 plugin the timebase delay settings can
be used to highlight a portion of trace for voltage measurement, and
any delayed timebase with a calibrated delay will effectively do
cursor time measurement. If you want on-screen digital readout of
delta-delayed time that comes in 1976 with the 7B85. So in the 7000
series scopes, I'd say that manually-controlled digital cursor
measurements of time and voltage were possible together for the first
time in 1976.

Chris










Re: 2445b shelf vents for bottom air intakes - should I?

Alex
 

As long as the scope has its 4 bottom legs intact and the bottom of the scope is separated by that amount from the shelf I'd say its enough. I use my 2465B sitting on top of my 2247A and the exhaust air from the 2465B does not seem to be restricted in the least. Its not like you are going to have a huge amount of airflow at those spots anyhow. I would think the design of those four bottom legs took into account that the scope could be ran while sitting flat on them on a solid surface. I am usually at 27-29 deg C ambient, unless I run the AC, but your mileage may vary.

Furthermore very knowledgeable persons extremely familiar with Tek designs have mentioned in this forum and others many many times that U800 as it is factory mounted is NOT heat sensitive as long as you have a normal airflow inside the scope, and certainly no huge dust accumulation. That is the reason why Tek never installed the planned heatsink after they ran some operational tests and found out it was not needed. I for one just left U800 alone and it works just fine.


Re: explosion mystery on my 7104

Keith
 

Hi Barry,

Curiously, my 2445b just blew the same part. unlike you, I got the smoke and the magnificent sonics and everything. Did you replace yours? My scope seems to be working fine without it, but of course this is an illusion, right? :-)

Weird that both our 2445 series would blow their tops at around the same time. Mine has about 20k hours on it.

Cheers,

Keith
coolblueglow


Re: What was the first oscilloscope to have cursors?

ken chalfant
 

Greetings,

I can’t prove it even looking back at my really old Tektronix catalogs - but, when I was in HS back in the late 1960’s a professor at the local college, what was then the Cragmor Campus in Colorado Springs, part of CU Boulder, would let me come up to their lab and mess around with test equipment.

They had a Tek scope that was as big (maybe bigger) than a Tek 556. It had a large plug-in on the right hand side that, as I recall, allowed for time measurements. It may have even been able to do amplitude. If my memory serves me it would allow the user to place intensified dots on the trace and it displayed the value on Nixie tubes within the plug-in.

Does anybody else remember a scope like this?

Ken

On 14Jul, 2021, at 1:09 AM, cmjones01 <chris@stumpie.com> wrote:

On Tue, Jul 13, 2021 at 8:05 PM nj902 <wb0emu@arrl.net> wrote:

Cursors as in highlighted dots (or bars) that can be moved along the trace with a corresponding method of determining time and voltage..

A second part of the question (if the answer is different) - which was the first Tektronix scope to have cursors.
Cursor voltage measurement on a Tek scope would have been possible in
1974, certainly. With a 7D12/M2 plugin the timebase delay settings can
be used to highlight a portion of trace for voltage measurement, and
any delayed timebase with a calibrated delay will effectively do
cursor time measurement. If you want on-screen digital readout of
delta-delayed time that comes in 1976 with the 7B85. So in the 7000
series scopes, I'd say that manually-controlled digital cursor
measurements of time and voltage were possible together for the first
time in 1976.

Chris




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