Date   

Re: Upcoming changes to our PayPal legal agreements

Rick
 

I didn't Paypal was a division of Tek


Novice X-Y Problem 2265

Alan Young <agyoung@...>
 

Hello all,
I am trying to use a 2246 for monitoring a two tone input in ch1 and 2 to look at the beat pattern of a transmitter.
When in X-Y mode I don’t see anything. If I push the beam finder I see the two dots all the way to the left and have superimposed them. The test setup is a demodulation signal from the tap to X and the Y is the RF sampler out. The device has a trigger port for triggering, using ch 3 for the trigger. When the transmitter is keyed and beam finder pushed in I can see vertical deviations of the demod signal but no movement in time. Without pushing in the beam finder I see nothing. I haven’t used a scope in 40 years, last one used was a 465.
Any thoughts would be helpful, and thanks in advance.

Alan
N5AGY


Re: FG504 pricing

 

I'm the enquirer, not Dennis. If you're in the UK please PM me.

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of SMOSborne@centurylink.net
Sent: 05 May 2021 04:01
To: TekScopes@groups.io
Subject: Re: [TekScopes] FG504 pricing

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: Scope camera weight

stevenhorii
 

There were camera bezel attachments for the various Tek scopes. I bought a
7704A that had a camera bezel on it (but no camera). My recollection (that
7704A went off at a hamfest years ago) is that the camera bezel was metal
and had a hinge where the camera would attach. The camera could be swung
out of the way for observation and swung in and latched for photos. The
7704A has grooves on the sides of the standard bezel into which the camera
bezel slid. This is all from memory which may be a little "dusty". This
arrangement to me suggests that the bezel on a 7704A can take quite a bit
of weight.

On Tue, May 4, 2021 at 1:16 PM Dave Seiter <d.seiter@att.net> wrote:

Marion,
I just put a c-53 on my shipping scale; it's 5lbs, 11oz. Center of mass
feels like it's about in the middle, so about 4.5"?
-Dave
On Tuesday, May 4, 2021, 10:06:49 AM PDT, Marian B <public@enkore.de>
wrote:

Hello TekScopes!

I've been finally getting around to making (or planning, anyway) a proper
camera mount for my Tek scopes. My main concern is if it's mechanically
O.K. to hang a camera on the front of my 7000-class ships (not
boat-anchors).

At the closest I can get to the CRT with my current camera + lens combo I
would end up hanging ~1.3 kg (2.9 lbs) onto the faceplate, with the center
of mass being ~24 cm (~10 in) in front of the scope. This seems awfully
heavy to me with a lot of leverage.

I searched for the weight of the C-50/51/52/53 series cameras which were
meant to go on these scopes, but didn't find it in the manuals. How do
these compare, mass and center of mass wise?

(I also own a 2246, but the attachment slot is out of thin plastic on
those, so I doubt hanging anything other than a hood on that is a good
idea)

Cheers, Marian











Tek 465

Dr. Manfred K. Zeller
 

"Y shift from channel 1 move only in the upper part of the screen vertically?"
A part is out of screen.
Amplifier discret version.
Power supply ok
Manual there
Serial B011126
Channel 2 is ok.
Thank you!
Manfred


Re: Repairing a 7704A - No Read-out...

Ulf Kylenfall
 

Several signals that should be present from interface boards
were not present. Scope will be used for spare parts...


P6006 style probes...loose connection at the BNC?

Sean Turner
 

Hi folks,

Recently I got me a beautiful Type 547, cart, and all kinds of goodies at an estate sale. Naturally it makes a good home for the Type 1A4 plug in I already had, and it came with one P6006 probe. I got two more P6006 recently (need to find a fourth!) but one one of these new ones has an intermittent connection going on near the BNC, Is there any way to get under the strain relief to fix it there, or is it hosed?

Thanks,

Sean


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

 

Glad to hear that you fixed the problem!

The sheet metal cover is easy to assemble incorrectly, and a number of 475s that I have handled (whose construction is almost identical to the 465) had their sheet metal covers assembled in various wrong ways. I don't entirely understand your fix, but you may have simply restored the cover to its correct configuration. It certainly should NOT have been pressing on the attenuator blocks.

These scopes can be operated with both 1X and 10X probes, which is why they have a probe readout sense ring (you're cheap Chinese probes almost certainly don't have a readout sense pin, so the vertical gain range lamps will be lit incorrectly, but that's merely an inconvenience). However, a 1X probe (or a 1X/10X probe in 1X mode) has very different bandwidth characteristics than a 10X probe (or a 1X/10X probe in 10X mode). In almost all cases you will want to have your probe set to 10X, unless you need the increased sensitivity of 1X mode, and can accept the drastically lower bandwidth.

-- Jeff Dutky


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

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