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BTW, you’ll notice that I’ve replaced the 2 missing pass transistors with TIP35C’s.
I checked the pinout, ans it seems to be the same as the MJE2801.

Yes Raymond,

This is the fuse I’m talking about.
Good pieces of advice, as usual. Thank you ?

On Thu, Apr 8, 2021 at 09:41 AM, Dave Peterson wrote:

Interleaved,

Stephen,

I don't quite have the equipment to scan the pre SN B250000 11x17 pages, but I
can take photos and look up specifics for you.

That would be awesome, thank you.

The A9 board has many board layout pages in the book. Each one highlights
components from different sections: Horizontal Amp, CRT, Power Supply, etc.

I’m sure...

Please let me know what you need and I'll upload pictures. It's kind of a
run-around to take and upload pictures, so a blanket dump would take a while.
My phone takes pics that are several Meg in size, so I resize them down to
something more on the order of several 100k. But it takes a bit of shenanigans
to do. I don't want to blow up the groups disk space.

Of course, I understand. Can you send them to me full size, privately maybe?

When you say the fuse blows, are you talking about the main fuse, or F1419?

I’m talking about the main fuse, the 0.750mA one outside the unit (the scope is set to 230V, I’m in Europe)

F1419 is the one on the board that drives the HV transformer. Quite common
that C1419 shorts and causes that.

F1419 is fine. Although C1419 was testing good, I replaced it anyways because I happened to have a brand new one just if front of me. I guess it was C1419 (can’t make out the number), the large 47uF/25V tantalum underneath the high voltage cover shield, in the corner.

If the main fuse you're going to have to
see if you can identify the short in the power rails. Do any of the power test
points measure 0 ohms to ground?

Nope... The 15V rail was shorted to ground before I even powered up the scope, and I fixed that already.
None of the low voltage test points are shorted to ground now.

As you know, some of the A9 board diagrams are already in your TekScopes photo
album. Let me know what's not covered that you think will help. Same with
schematic pages.

Yes, But I’d like, if possible, to have as much as I can with the parts labeled.
I’m posting a few pictures of my A9 board after it’s been cleaned up quite a bit.
Look at the first 3 pictures in the album to get an idea of what board version we’re talking about.
Note the lack of that big resistor between the filter caps, and the slightly different layout when compared to newer units.

/g/TekScopes/album?id=262670

Thanks Dave.

Dave

Hello Joe,

I use a capacitor checker from Mr. Carlson's Lab, and that works very well. As far as your list of capacitors goes, I have had very good luck with Good-All capacitors! I have checked many of them and they were doing very well with no leakage. However, I have yet to find 1 Bumble Bee that is not leaky. I still test those but most likely they are replaced. High voltage capacitors, well, my checker can test them for leakage, but if the are the disc type, those should be fine. I have found the the Black Sprague capacitors goes, there are 2 different colors. And in my experience, the black caps with the yellow writing tend to be very leaky while the ones with the red writing don't have the leakage issues. I have one of those Chinese testers myself, does a rather pretty good job for a go-no go test!

Seleniums on the other hand tend to scare me. It's only a matter of time before those will fail, and I had one blow out that nasty smoke and believe me, was not pleasant to deal with. My whole house reeked for a long time before it cleared out. I actually have a conversion kit pulled from an old 531 scope sitting around somewhere, but I don't know if that would work with a 575. That is one piece of Tektronix equipment that I would love to have.....for a reasonable price that is.

Brenda

On Thu, Apr 8, 2021 at 10:30 PM, Stephen wrote:

Now that I’ve replaced what I could so far, I turn the unit on, and the line
fuse blew instantly.

I guess by line fuse you mean mains fuse. Assuming that's correct, I'd start by looking at the usual suspects for this 'scope family:
See schematic dwg 12, ckt. layout in fig. 7.21: Bridge rectifiers, buffer caps, overvoltage protection circuit (around Q1514). VR1515 being shorted is a candidate. Check with current-limited voltage across Q1514 but only for a short moment, because C1512 will be reverse-biased. Just tap the test voltage for a second or so. 10V to 20V usually makes a bad circuit trip (shorted Q1514 or VR1515).
Check by connecting current-limited DC across each of the buffer caps separately, starting from a few volts.
If no shorts observed, check individual diodes in diode bridges.
All this in-circuit but *with mains plug disconnected*.

Raymond

Stephen,

I don't quite have the equipment to scan the pre SN B250000 11x17 pages, but I can take photos and look up specifics for you.

The A9 board has many board layout pages in the book. Each one highlights components from different sections: Horizontal Amp, CRT, Power Supply, etc.

Please let me know what you need and I'll upload pictures. It's kind of a run-around to take and upload pictures, so a blanket dump would take a while. My phone takes pics that are several Meg in size, so I resize them down to something more on the order of several 100k. But it takes a bit of shenanigans to do. I don't want to blow up the groups disk space.

When you say the fuse blows, are you talking about the main fuse, or F1419? F1419 is the one on the board that drives the HV transformer. Quite common that C1419 shorts and causes that. If the main fuse you're going to have to see if you can identify the short in the power rails. Do any of the power test points measure 0 ohms to ground?

As you know, some of the A9 board diagrams are already in your TekScopes photo album. Let me know what's not covered that you think will help. Same with schematic pages.

Dave

Hello,
as I had initially planned my objective was to exchange all and every "suspicious" capacitor and these selenium rectifiers. Right now I have got a basically well operational instrument, but not yet calibrated as I am still looking for other suspects.

My findings (results read from a Chinese component checker):
1. Bumble Bees: all 10 - 35% off nominal value, VLoss 1.0 - 2.8%
2. High Voltage capacitors (1kV, 3kV, ...): VLoss 1.5 - 2.0%
3. Good-All capacitors: 5 - 12% off nominal value, VLoss < 1%
4. Black Sprague capacitors: 15 - 30% off nominal value, VLoss 1.2 - 2.4%
I have tested that Chinese instrument against a Siemens metal casing precision capacitor of 90.000 pF 0.5% first and it gladly agreed to the printed on values ;-)

So I believe it was very well necessary to retire ## 1,. 2. and 4. whereas these Good-All seem to be still strong.

Next I will have a look how well the seleniums perform. Let's see!

Regards, Joe

I finally started to electrically restore this apparently quite early 465.
The 2 pass transistors have been replaced, as well as R1549, and C1549.
Also, the 15V rail was shorted to ground because of a faulty tantalum on the horizontal amp board, but I don’t know the number. The schematic from TekWiki is not very good. It’s near impossible sometimes to make out the parts numbers.
Also, some A9 board pictures do are quite different from the one I have.
Could anyone with a legible picture send it to me offline, or post it in the photo folder, please?
Now that I’ve replaced what I could so far, I turn the unit on, and the line fuse blew instantly.
I can’t try to troubleshoot it with the documents I have available at this point.

PS: No more of the rails are shorted to ground.

Rebonjour a tous,

WOW Perfect, I have never seen this VERY useful référence!



VIVE LE GROUPE TEKSCOPE !

Jon

On Thu, Apr 8, 2021 at 08:30 PM, Raymond Domp Frank wrote:

the 2465A and 2467 use a regular fan and a regulation circuit using NTC (not
marked as such) R1110, page 327/424, dwg 9 in my SM.

Sorry, RT1110, not R1110

Raymond

On Thu, Apr 8, 2021 at 08:15 PM, <durechenew@...> wrote:

I believe somebody mentioned the fan for 2465A(B?) or 2467 with driver circuit
with an NTC; I didn't find than NTC in schematic, maybe I don't have the right
one... The idea of a regular fan with that (thermal) controller (or another,
maybe from a 2465 modified for the need) is attractive (I have some fans of
high reliability).

According to my info,
the 2465 uses a Hall-element motor and the NTC is R1696 (page 262/323 in my SM), the 2465A and 2467 use a regular fan and a regulation circuit using NTC (not marked as such) R1110, page 327/424, dwg 9 in my SM.

Raymond

Thank you for confirming, Dave!
And I agree with you that it's bad etiquette to hi-jack a thread; no matter what was my reason it was wrong. I regret it and I apologize to all that were offended by my action.
TT

Thanks to all for the great interest this has started and for more than interesting information presented. Great, great article at antiqueradios; whoever's ready for that work, good luck!
Not going to work for me, as part of the bushing holder is broken and I think that's no repairable. I believe somebody mentioned the fan for 2465A(B?) or 2467 with driver circuit with an NTC; I didn't find than NTC in schematic, maybe I don't have the right one... The idea of a regular fan with that (thermal) controller (or another, maybe from a 2465 modified for the need) is attractive (I have some fans of high reliability).
Thanks all for thoughts
TT

On Thu, Apr 8, 2021 at 06:55 PM, Raymond Domp Frank wrote:

Common Design Parts Catalog 1, August 1979, "Semiconductors", lists lamps in
chapter 15.

Tekwiki link:


Raymond

Great info. If you can get the bearings/bushes in hand first, it might be an idea to go for it. You can always buy the magnet wire easily. The fun is getting it working like when it came originally!

Except for Instruments Used In, the info is already available in Section 15 of Common Design Parts Catalog – Semiconductors.


Dave Wise

From: [email protected] [mailto:[email protected]] On Behalf Of greenboxmaven via groups.io
Sent: Thursday, April 08, 2021 9:47 AM
To: [email protected]
Subject: Re: [TekScopes] TEK CX ref lamps

If someone does this very desirable and valuable work, and any other
for that matter, PLEASE! provide the option of receiving it in PDF form.
Thanks,

Bruce Gentry, KA2IVY


On 4/8/21 12:40, Jean-Paul wrote:

Hello all: Seeking a cross ref of all Tektronix lamps
TEK part # like 150-0090-00
spec volts, current, envelope
instrument used in,
industry lamp type #

Would be very handy! If it does not exist perhaps one of our members could help to compile in easily exchangeable form eg Excel XLS?

Bon Journee,


Jon

On Thu, Apr 8, 2021 at 06:40 PM, Jean-Paul wrote:

Hello all: Seeking a cross ref of all Tektronix lamps
TEK part # like 150-0090-00
spec volts, current, envelope
instrument used in,
industry lamp type #

Would be very handy! If it does not exist perhaps one of our members could
help to compile in easily exchangeable form eg Excel XLS?

Common Design Parts Catalog 1, August 1979, "Semiconductors", lists lamps in chapter 15.

Raymond

If someone does this very desirable and valuable? work, and any other for that matter, PLEASE! provide the option of receiving it in PDF form. Thanks,

??? Bruce Gentry, KA2IVY

Hello all: Seeking a cross ref of all Tektronix lamps
TEK part # like 150-0090-00
spec volts, current, envelope
instrument used in,
industry lamp type #

Would be very handy! If it does not exist perhaps one of our members could help to compile in easily exchangeable form eg Excel XLS?

Bon Journee,


Jon

The Grayhill 71BDF30-20-2-AJN multi-way switch(Digikey GH7108-ND) is out of stock at Digikey ?

Mouser has a few (16) and lead time is 16 weeks.

Master Electronics, Electrosonic, and Verical also have limited stock (14 or 15).

David