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Re: Tek 465B Diagnosis Comments Requested #photo-notice

 

Thank you. But this response came too late. I have already buttoned up the project, calling it finished. Now that I know those little rectangular white plastic blocks are actually easily removed, I "fixed" my problem another way. I had already cleaned the contacts, best as I could with those blocks in the way. Here was the problem: I noticed that both channels behave more or less the same way when my cheap chinese probes are set to 10X, when the sheet metal cover of channel 1 was off. But as soon as I tried to put the little sheet metal cover back on, the trace would get pointed and noisy again. That cover is a snap-on arrangement, and it was squeezing together the metal sides of the attenuator mounting bracket. So what it did was bend one of the flanges of the cover outwards out so it didn't squeeze and snap on. Now it is only held in place by the 5 little screws. Now both channels behave almost perfectly identically. What i also learned was this scope doesn't like when you set the switch the probes to 1X. Apparently the correct way to operate this scope is with the probes set at 10X all the time. I believe I like this scope better than my 2215, even though my 2215 is light as a feather and works absolutely perfectly. This 465B has the DM44 volt/ohmeter on top. From what I read, it has a 10meg impedence on the voltmeter, which means you can use it as a VTVM. Is that true? Thank you. PS: this 465B is a sweet machine.


Re: TM-500 Test Module Question

Mac Perkins
 

I noticed something similar, some slots in some of my TM5XX frames drop down below 10 mV, others don't, with several in a late production TM506A that won't drop below 50mV.
I have not torn into that frame yet as it passes all other tests with reasonable beta on the transistors. I will be interested to see what transistors are in there.

I agree that connecting the BNC shell to ground makes the most sense, if it is floating and connected to the METER LOW terminal and a scope with a grounded input BNC (virtually all AC line powered units) is connected, the METER LOW terminal will be shorted to ground via the power connection safety ground.
The original construction note does not show a connection for the BNC shell.

I have tested about half of my frames and found several with issues, mostly pass transistors, but one slot with a phasing problem which I had suspected but was too lazy to test it.

Thanks again to Jared for making building the tester so painless and Larry for handling the group buy.

-Mac


Re: Tek 465B Diagnosis Comments Requested #photo-notice

 

It sounds like the attenuator blocks have dirty contact pins. The solution to this is to clean the pins of the attenuator blocks with a cotton swab and isopropyl alcohol. The procedure is fairly simply: one at a time, remove each attenuator block, clean it's pins with the swab dipped in anhydrous pure isopropyl alcohol, and reinstall the block. You should only remove one block at a time so that you don't get confused about which block goes in which socket. This is a known problem with the 465 and 475 scopes. It also happens to the socketed transistors and ICs elsewhere in the instrument, and those can be fixed by the same procedure.

The attenuator board does not need to be removed. You can unseat each attenuator block from the top using the same access you currently use to "press down" on each block. You can gently rock the block back and forth lengthwise to unseat it from its socket. You might want to use a small tool to gently lever the block out of its socket incrementally from alternate ends.

-- Jeff Dutky


Re: Tek 465B Diagnosis Comments Requested #photo-notice

Dave Peterson
 

I'm not familiar with the 465B yet, but my first examination of the innards shows it is very close to the earlier 465.

Review the Maintenance section of the Service Manual available on Tek Wiki (make sure you're accessing the correct manual for the 465B, not the earlier scopes). The Maintenance section of the 465 (earlier) gives a good description of the removal of the vertical assembly on the left side of the scope. I'd be surprised if the 465B SM didn't give a similarly good disassembly procedure.

The 465 procedure involves unsoldering the input capacitors (the small metal cylinders inside the attenuator shields). Then behind those caps are 4 1/4" nuts that have to be removed. They are what hold the board to the face. Aside from taking off the volts/div knobs, you don't need to disassemble anything from the face. The BNCs are attached to the vertical board, not the face.

Otherwise it's bits-n-pieces that should be apparent to disconnect the rest of the board. You'll probably have a few small wires to unsolder to free the board. Along with screws and connectors in plane sight.

Good luck!
Dave

On Tuesday, May 4, 2021, 09:22:08 PM PDT, henryfinley <tomsradio@gmx.com> wrote:

I have a problem on my Tek 465B. On channel 1 the square test wave doesn't display right until I tap or push down on the rectangular white plastic adjustment blocks on the attenuator board. Every time I change the VOLT/DIV knob, I have to tap or push down on one or the other of the first or second block (counting from the front of the scope), to get the squate wave to display correctly. I suspect possibly a bad solder joint on the underside of the board. but I can't figure out how to get the attenuator board out, aside of taking odd all the knobs so I can get the front panel off, so I can get to the bracket screws, so I can take out the attenuator board. Certainly there has to be a better way. Thank you.


Tek 465B Diagnosis Comments Requested #photo-notice

 

I have a problem on my Tek 465B. On channel 1 the square test wave doesn't display right until I tap or push down on the rectangular white plastic adjustment blocks on the attenuator board. Every time I change the VOLT/DIV knob, I have to tap or push down on one or the other of the first or second block (counting from the front of the scope), to get the squate wave to display correctly. I suspect possibly a bad solder joint on the underside of the board. but I can't figure out how to get the attenuator board out, aside of taking odd all the knobs so I can get the front panel off, so I can get to the bracket screws, so I can take out the attenuator board. Certainly there has to be a better way. Thank you.


Re: 561A early s/n HV supply

Ondrej Pavelka
 

Hi Roy,
It's not really an option for me because in my unit the transformer as well
as valves and associated caps in the HV section are physically missing.
There are empty ceramic strips and two holes where transformer used to be
mounted

On Tue, 4 May 2021, 16:45 Roy Morgan, <k1lky68@gmail.com> wrote:

Ondrej,

I knew a fellow who taught college electronics classes (at Cornel).

Their lab had a number of 561's that were idle all summer. They followed a
regular necessary procedure to get them running each year. The HV
transformers would gather moisture and had to be dried out.

They ran an incandescent lamp to heat the transformer moderately for a day
or two and the scopes would operate normally.

I suggest you try that.

Roy

Roy Morgan
K1LKY Western Mass

On May 4, 2021, at 2:31 AM, Ondrej Pavelka <info@vintageaudiorepairs.eu>
wrote:

Thank you!

I don't think it's about rewinding rather then making a new transformer
0-200-300 primary and 2370 and 2440 specified for 35kHz

Today's materials designed for 40kHz or even 300kHz switchers should make
it easier to wind compared to the original construction.

I will explore the options and get back to you.





Re: Transporting a 500-Series Scope without Breaking the CRT

 

Also, one of the ground posts on the CA plug-in is missing its knurled head or thumb nut (I'm not sure what they are actually called, but this is what turned up after some googling). Unlike later service manuals, while there is a list of replaceable mechanical parts, there is no drawing showing which part is which. I'm not sure if the ground posts are the POST, BINDING, ASS'Y (Tek P# 129-053) or the TURRET, SOCKET ASS'Y (Tek P# 123-007) or maybe the knurled nut is NUT, KEPS, 6-32x5/16 (Tek P# 210-457).

A very rough guess (using a rule, hardly a precise measurement) is that the ground binding posts have a major diameter of about 1/4 inch, and a thread pitch of about 32 TPI. The nuts themselves have an outer diameter of between 3/8 inch and 13/32 inch, with a "diamond knurling" pattern, and are about 11/32 inch long. If I can find a modern part that will fit the post I can simply replace them both, and at least they be consistent, even if they aren't strictly authentic.

I suspect that the nuts on the binding posts for the SC502/503/504 (Tek P# 220-0633-00) might work, but also that they will be a bit too short (still better than nothing). Another option would be to obtain a parts unit from which to scavenge the binding post head nut. I'm actually leaning toward that option, since the CA plug-in that I have appears to have been the subject of some diagnostic manipulation, meaning that a parts mule may come in handy for more than the binding post nuts.

-- Jeff Dutky


Re: FG504 pricing

@Arcticgeek
 

Dennis,

I have an FG504 that is working that I no longer want/need and would be willing to sell at a reasonable price. Contact me off list if you are interested.


Re: PG506 Repair - I had a Great Day today/

Mlynch001
 

Forgot the link

PHOTOS ARE HERE: https://www.icloud.com/sharedalbum/#B0e532ODWGRrNkO
--
Michael Lynch
Dardanelle, AR


Re: Transporting a 500-Series Scope without Breaking the CRT

 

Bruce,

But the shafts we are talking about here are actually attached to a stack of two pots behind the face plate. I would not expect a solvent to make its way into the second pot in the stack.

These are marked as Allen Bradley (A-B) Type J pots. The rear pot on the vertical position stack appears to be marked as 0.1 MEG, which seems an odd way to say 100 KOhm.

What kind of cleaning solvent are we talking about?

-- Jeff Dutky


Re: PG506 Repair - I had a Great Day today/

Mlynch001
 

Here are photos of the wave forms from U400 and U470 of the PG506. The photos are keyed to pins as referenced on the last two photos of the series. These were obtained using my TDS460A. Most pins have 3 photos, one at Full CCW, Zero and Full CW variable. Std amplitude set at 1.0V.

Any questions, feel free to contact me as needed on or off list.

Hope this helps.
--
Michael Lynch
Dardanelle, AR


Re: What's a chat.. and why?

nielsentelecom@sbcglobal.net
 

You both have a point,,, but I'm always telling myself that I'm right all the time,,, and my wife she says, well that's waaay OT now!

This would be a great topic for a group about Groups.Io on Groups.Io usage best practices etc. Maybe there is one!

I have a sneaky feeling the Moderator is going to give me the boot now despite the reassurances that he is the OP!

NielsenTelecom


Re: Transporting a 500-Series Scope without Breaking the CRT

greenboxmaven
 

If pots are stiff to turn, remove the knob and put on a knob that allows you to get to the area where the shaft enters the bushing. Orient the plug in so the shaft is upward, and apply cleaning solvent to the shaft and bushing. Turn the shaft back and forth, keep a drop of solvent on the shaft where it enters the bushing and be patient. It will work,it's way in and the shaft will turn freely. Once it is free, put a drop of synthetic engine oil on the shaft and bushing, work it in, and it should be fine for years. If the actual pot or switch is scratchy, find out how to get some contact cleaner inside the pot. All of the position pots I have seen on older Tektronix plug ins are not sealed and cleaning the element and wiper is not difficult.

    Bruce Gentry, KA2IVY

On 5/4/21 19:06, Jeff Dutky wrote:
I've cleaned up the CA plug-in with a toothbrush and warm, soapy water, and it looks almost new now. I've used DeOxit on the switches, which improved the switch feel 100%, but the vertical position pots (and assume the other pots) are quite gummy and stiff, and I don't see a way to get lubricant into them. Do I need to disassemble the pots, or are they not sealed?

-- Jeff Dutky




Re: FG504 pricing

Siggi
 

Þann þri., 4. maí 2021 kl. 20:02 skrifaði Dennis Tillman W7pF <
dennis@ridesoft.com>:

Hi Siggi,
This is the first I have heard of ShapeWays, and your great brackets. I
just bought six of them. How does this work?

They print them off in some kind of nylon IIRC and ship them to you.

Do you get a royalty for each one they sell?


No, though it’s possible to set that up. You can also print in other
materials with them, so you can e.g. do sintered metal trinkets or jewelry.

What else do they have for Tektronix stuff?


Not much that I’m aware of. I also modeled the TM500 quarter turn latches,
but I’ve never pulled the trigger on a print yet.

This kind of service is - in principle - great for producing spare plastic
parts for our darlings. They can print pretty much anything that can be
injection molded.
The problem is that the process is fairly labor intensive, as they batch up
little objects into a full bed print for some kind of sintering machine.
Afterwards a human has to sift through a tub full of spare media to locate
the parts for shipping. There’s therefore a per item cost that dominates
the price of very small items, as I understand their pricing model.


Re: Transporting a 500-Series Scope without Breaking the CRT

 

Take the knobs off and with the shaft pointing up, run a bit of oil down the shaft. I use PB Blaster but there are many others that will do the same.

Tom

On 5/4/2021 7:06 PM, Jeff Dutky wrote:
I've cleaned up the CA plug-in with a toothbrush and warm, soapy water, and it looks almost new now. I've used DeOxit on the switches, which improved the switch feel 100%, but the vertical position pots (and assume the other pots) are quite gummy and stiff, and I don't see a way to get lubricant into them. Do I need to disassemble the pots, or are they not sealed?

-- Jeff Dutky



--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: Scope camera weight

greenboxmaven
 

The Impossible Project, now owners of  Polaroid, are very much in business and are selling plenty film for the newer cameras, as well as refurbished SX-70 cameras themselves and others. They receive a constant deluge of inquiries and requests to resume making pack film or provide a viable replacement. There was a company called Cat Labs that put a good deal of effort into it, but concluded it was not practical. Oddly, the chemistry is not said to be the issue. The construction of the cartridges and assembling the negative, pods, and positive papers reliably and assembling the cartridge in the dark is the big hurdle. What I can't approve of is Polaroid and Fuji wrecking the equipment so no one else can make a product (covered by long expired patents) they don't want to bother with anymore. I don't expect the demand and requests for pack film to go away, there is too much equipment around that uses it, and the artisic merit of the film both b&w and color is great and essentially irreplaceable. Don't throw away good quality VHS camcorders or Tektronix analog monitors. There are fim makers who are increasingly interested in the ambiance of modest quality video.

   Bruce Gentry, KA2IVY

On 5/4/21 18:38, Dave Seiter wrote:
I was wondering what the status of the Impossible Project was; hadn't heard anything about them in a long time.
-Dave


Re: Scope camera weight

greenboxmaven
 

If this was true, it's actually a realistic test. As I have said before, not all Tektronix gear was used in a lab or ordered environment. When an engineer at a TV station was behind a rack of equipment, trying to find an intermittent problem, with a supervisor breathing down their neck, and the station manager pokes their head around the corner to deliver additional "motivation", the engineer is likely to flinch. If the test lead from the scope is near it's full length, the harried engineer is quite capable of yanking on it out of fright and a "What the @#$%! are they going to do to me NOW!" startle. Amplify this ten times over for an elevator or indutrial control technician. If the probe and lead stay intact and operational, the engineer is likely to have their loyalty to Tektronix greatly enhanced. As for power cords, if circumstances demand and the cord has a good molded on plug, pulling it out occasionally with a gently increasing force is unlikely to damage anything.  It's the real world, after all!

   Bruce Gentry, KA2IVY

On 5/4/21 18:35, Dave Seiter wrote:
That's jaw dropping!  Was era was that?  I hope it was portables and not 555s!  Neither would be wise, of course.  On the other hand, I frequently pull plugs out of the wall by yanking on the cord, instead of pulling on the plug.  Laziness, I guess.
-Dave
On Tuesday, May 4, 2021, 01:21:18 PM PDT, Dennis Tillman W7pF <dennis@ridesoft.com> wrote:
Hi Martin,
This reminds me of a conversation I had with an ex-Tek employee who worked on probes.
Among other things I asked how they decided on the wire they used for the probes.
I thought it would be nice if it was thinner or more flexible. His answer stunned me.
He said they did a little field research where their scopes were used to find out why some probes broke more often than others.
What they saw was the engineers pulling the scopes on the scope carts by their probe leads.
For a long time after that scope probes had to pass that test.


Re: FG504 pricing

 

Hi Siggi,
This is the first I have heard of ShapeWays, and your great brackets. I just bought six of them. How does this work? Do you get a royalty for each one they sell?
What else do they have for Tektronix stuff?
Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Siggi
Sent: Tuesday, May 04, 2021 1:27 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] FG504 pricing

Hey David,

I paid $90 plus shipping for mine back in 2015. It had some problems, notably the brackets that hold the PCB straight for the edge connector were broken.
I drafted this replacement
https://www.shapeways.com/product/CGNES54EY/tektronix-351-0449-00-pcb-bracket,
which can be bought straight from Shapeways.

Siggi

On Tue, May 4, 2021 at 5:27 AM David C. Partridge < david.partridge@perdrix.co.uk> wrote:

I'm considering purchase of an FG504, what should I expect to pay for
a good one? For a needs repair one?

Thanks
David












--
Dennis Tillman W7pF
TekScopes Moderator


Who was looking for a 5 turn Helipot with 1/8" shaft

 

Whoever was looking for a 5 turn heliport with a 1/8" shaft in the past few
days please contact me off-list at dennis at ridesoft dot com.

I may be able to help


Re: Nice 541 package in Tysons Corner VA

-
 

I saw one of these at the Titusville (Florida) hamfest about 12 years
ago. It worked and had the cart and the manuals and extra plugins just like
this one. The owner started off wanting $75 for it but continued to drop
the price throughout the day. By the time that I left at about 4 PM he was
down to $5! Everyone there had stopped and looked at it all day long but no
one wanted to take it home.

FWIW

On Tue, May 4, 2021 at 5:15 PM Daniel Koller via groups.io <kaboomdk=
yahoo.com@groups.io> wrote:

Hi all,
just saw this on Craigslist in Tysons Corner VA. I have no connection to
the seller that I know of.
https://washingtondc.craigslist.org/nva/ele/d/vienna-oscilloscope-tektronix-type-541/7311224920.html

It was posted 12 days ago, but it's still up, so might be a nice deal for
someone. Comes with an older style (brown) cart, type CA and A plug-ins
and probes. It is shown with a trace, but from the apparent 60 cycle hum
shown on that trace, I surmise the filter caps are dying and need to be
re-formed or replaced.
Dan





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