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On Sat, Mar 29, 2025 at 01:42 PM, Jay Czaja wrote:

I just cracked it open and checked the DC voltages and ripple. Everything was
well within spec. The inside also looks very clean!

Just check the power supply diodes for either ZM or ZS markings and replace. And the 3V battery.
Should then be done and ready to enjoy.

On Sat, Mar 29, 2025 at 09:57 AM, Jay Czaja wrote:

Thanks again guys! The 2247A has been running overnight with signals in each
channel and everything has been humming along ok, no lockups.

Just replace the 3V battery to get rid of the annoying power up error message and the recalibration routine running every time. You need to lift the main processor board that is on top, and the battery is at one end of the board. To lift the board there are some flat ribbon type conductors and connectors to deal with, but if you are careful and methodical its pretty straight forward procedure. Last time I recall the battery swap can be done by just partially lifting the board, which limits the amount of ribbon cables to deal with.

I have a really nice 2245A and enjoy using it and always wanted a 2247A.

The 47A is a 45A with additional digital functions (and push buttons), otherwise they are identical scopes. Make sure to check those suspect diodes on the power supply board in both your 45A and 47A scopes. A quick glace should tell you if you need to replace them. The power supply board is in the middle of the lower side, kind of a pain to get it out and even more pain to get it back in due to the connecting pins. But you should be able to read the labels on a couple of diodes without removing the board to make sure you don't have any time bombs sitting in there.

If you find voltages and ripple specs are ok I would not even bother recapping unless you see a capacitor that is obviously leaking or bulged up, which I doubt.
These 224x scopes if I recall used high quality Mallory or Sprage caps, and I've never bothered to replace any in my 47A, but most definitively had to in my 2465B.
Those old caps sometimes even end up measuring better specs than modern equivalent caps (value/ESR).

Thanks for all the comments / suggestions! Keep them coming!

I used a similar procedure as Tom, but I prinetd the image on a self adhesive transparency film.
Pay attention to print the image "mirroed".
After the film was glued to the skirt, I spayed a layer of protective varnish to minimize the chances of the image being "washed out" due to friction of the skirt and the panel.

On Sun, 30 Mar 2025 at 00:17, Barry Breaux via groups.io <groupsio=
[email protected]> wrote:

I need to re-letter the skirts for some of my scope knobs. Has anyone done
that here?
...
Other suggestions are welcomed!

I needed to do that for my 475.

I used a standard word processor diagram package to draw the label. I used
"Ubuntu Condensed 7 pt bold". While creating the legend I found it useful
to add lines/circles indicating where the text ought to be, but to not
print those. Rotating the entire picture (by the relevant number of
degrees) for each setting enabled me to ensure that each setting's text was
correctly oriented.

I printed the label on a transparency; I forget whether I used an inkjet or
a laserjet on the high temperature stock; probably the former.

I then mounted the transparency behind the existing skirt to protect it,
and held it place with a dob of glue in the centre. Theoretically the
transparency could flap around, but in practice it was sufficiently stiff
for that not to be an issue.

Discussion about any Tektronix test gear is welcome here.

Barry,
Brother label tape is available in Black on Clear, and the label makers can do reverse print. I don't know if the available fonts would be the right size. The individual tape pieces might be a bit unsightly, too.
--John Gord

On Mar 29, 2025, at 17:16 , Barry Breaux via groups.io <groupsio@...> wrote:

I am thinking that black vinyl reversed letters on transfer stock would work. I found a few sites that provide that service, but I am not sure if they can deal with the small size that would be required. Not sure if a design tool is available online.

In one of this books, Giovanni Becattini recommended water slide decals for push button labels, and they work great. I wonder if the same thing might work for knob skirts?

The decals are transparent, and you could lay out the entire label at one go in a drawing program. You could either draw it in reverse and apply to the inner side of the skirt, or cut a hole in the decal and apply to the outer side.

Clear polyester label (sticker) paper might work as well, but the stuff I've tried isn't as transparent as the decals.

Adam

I was working on 2230 which has power supply failure.
Changing the main bridge rectifiers CR901... CR904, Q9070 and Cr907 restored the power supply. The scope power ons with an issue CDT issue CDT value changes from 73 to 77 during different sessions of power on.

After pushing the one of the menu scrolling key CDT goes off.
I have following display issue:
1. No trace
2. Readout tex for volt/div and sec/div display.
3. Intensity and focus works
4. Sec/div switch in A mod doesn't work.
I can see only 50m 5ns and. 2s changing the position of switch.
5. Horizontal position switch works but only for half portion of the screen.
What I did so far.
1 since there is no trace just a dot I started to
Look for horizontal section.
2 looked for ramp signal at waveform 24 and 29 but I could not see any just a dc offset.
3 decided to clean the sec/div switch so according to the instruction I pulled out A4 board which contains sec/div switch. In the A4 boaed I found strange connection. Collectors of q742 and q732 are tied together and connected to A sweep input of U760 while B sweep input is left floating.
I will be thankful if some one in this forum suggest on this issue and guide me to resolve the issue of my scope.
Thanks
Saroj

Suggest use a metered variac,

No diode test fix needed, easy to just use banana plug jumper cables and Alligator clips to put any diode or 1 k resistance as load.

Bring line to 30v, observe mains current, raise to 60, 90, 120, observe normal mains current

Should have a trace or dot on the CRT, be careful with the intensity

Jon

I have one of them left the 154-0934-00 I live in Utha about 60 miles south of Salt Lake City

Mark
W7HPW

Real Radios Glow in the Dark

For printed circuit board use, there's a paper/toner transfer sheet that is printed on (laser printer), laminated to the board (makes the toner melt), and then is soaked off (special coating (cornstarch?) on the paper.

It is also recommended for decals, so printing on some of it, soaking it, and using it as a transfer might help.? Never tried it, though.

Harvey

Greetings!

I need to re-letter the skirts for some of my scope knobs. Has anyone done that here?

I am thinking that black vinyl reversed letters on transfer stock would work. I found a few sites that provide that service, but I am not sure if they can deal with the small size that would be required. Not sure if a design tool is available online.

Other suggestions are welcomed!

Thanks,

Barry

Hey all,

So, based on some exchanges in the thread about the Dennis Tillman PCB for the 577/677 build, I am definitely on my way (parts are coming). But I wanted to start a new topic on the 577 itself to get some advice.

This is a 577 that's in very nice condition and when I bought it in 2020, it was sitting in the seller's garage with a trace on the screen. I realize that doesn't mean a whole lot. But here we are 5 years later and, at some point, I'm going to have to bring her back to life.

So, I'm looking input on next steps. For example, should I warm it up slowly (and over what period of time) with my variac, etc. Or maybe do some diagnostics on the power supply before plugging into mains. And so on. I have a variety of test adapters but, given the power up sequence suggested in my operator's manual, the one that I don't have that I apparently need is the axial diode adapter

Thanks in advance for any replies.

David

+1 on all of Menahem's points. In fact, I'd advise, instead of looking for
an NOS cap (I think this is what the OP is asking), procuring a new one of
adequate specifications, which will likely have far better specs and
smaller size anyway.
No application I'm aware of is sensitive to the exact value of an
electrolytic - particularly as all of them, and especially the old types,
have relatively large tolerances.
Radu.

On Sat, Mar 29, 2025 at 10:18?AM M Yachad via groups.io <yachadm=
[email protected]> wrote:

Not speaking from any particular authority on the merits of THAT
particular cap, but why not a regular 105°C 390uF or 470uF rated at 80V?
The circumstances which require an EXACT replacement of the original, are
very few and far between.

Menahem

There is a tek500 group. I found this very interesting since I am currently wrapping up a 10Hz->100kHz ultralow distortion signal generator project (-140dB THD, so far, at 1 kHz)

I just cracked it open and checked the DC voltages and ripple. Everything was well within spec. The inside also looks very clean!

I didn't notice the tag earlier but it appears to have been taken from a hospital environment. It was a bit of a pain to pull the chassis from the case. Of course, the only tiny dent on the top of case was putting enough pressure on the side rails to make it difficult for the chassis to slide out without resistance.

I'm guessing you might be right and maybe the caps needed to reform or something along those lines. At this point I had the scope running for hours. Left if unplugged for a few hours and had it running for a few more hours and everything seems to be ok.

I'll probably recap it in the near future as I plan for this to be my everyday scope w/ my 2232 for 'slower' stuff.

The 'green screen of death' had me a little worried but feel relieved that it's been stable since those initial issues. All functions I've tested so far have worked perfectly. I'll need to play around with the menu and measurements system a bit more but the few quick measurements I've made were good. I need to read about the menu/measurement section as it has more features than the 2245A which I've been using.

I appreciate all the responses. I'm sure I'll have more questions!

OOPS, not a 'scope. Sorry, delete if necessary.

On Sat, Mar 29, 2025 at 12:57?PM Jay Czaja via groups.io <jmczaja=
[email protected]> wrote:

Thanks again guys! The 2247A has been running overnight with signals in
each channel and everything has been humming along ok, no lockups.

Sounds like a keeper to me!
If the scope has been in storage for a while, it's possible that the power
supplies stabilize as the caps reform or warm up or some such. You may
still want/need to recap it, and I've never heard of a case where the
calibration is thrown off by improving the power supplies. I've never
worked on a 2247A, though, so YMMV.

On Sat, 29 Mar 2025, Jon Nicoll wrote:

Until recently DigiKey (?) had replacement buttons in stock. It is just that
button part that is attached to the plastic or metal driving rods that were
used in many devices with such buttons, not just Tek 24xxx. They even had it
is different "eye" colors, not just that acid yellow. I still have some red
and yellow ones somewhere in my stock.

The exact one used in 2465B and such was C&K F08010106 (Yellow) or F08010108
(Green).

BTW, they were also made square and rectangular caps, not just round.

Here is the DigiKey part number page (out of stock, but does have datasheet
with all those buttons of all types and shapes (at the end of the datasheet
which is for pushbutton SWITCHES and those buttons are at the end of it:



Once upon the time they actually had those in stock and I was able to
purchase some.

BTW, if you enter "F08010106" in Octopart search you'll find many still in
stock and they are dirt cheap -- e.g. Arrow/Verical has 160 of those in
stock as of right now for 64 cents apiece. They even have them in different
colors, Yellow, Blue, Green, ans Orange (last 2 digits 06/07/08/12).

As an afterthought, will probably go buy some more in all colors, just to
have spares...

Thanks Greg - I got a replacement but the fine details of how this one operates does not exactly match that used in the 2465. As you say, the plastic construction is pretty delicate.

I will take another look but unless I find an easy source I think I am going to live with this.

Regards, Jon N

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