Date   

Re: TDS-520

 

Also, are the 0 Ohm resistors 1%, 0.125W, TC=100PPM, 1206, T&R like on the TDS-520B?
Love that!

Raymond


Re: Tek 2465b with down shifted display..

Siggi
 

On Wed, Jan 3, 2018 at 16:20 Mark Hatch <mark2382@hotmail.com> wrote:

Siggi

Thank you for the reply! The 2456b did arrive and it now appears to have
what appears to be classical u400 failure. Channels 3 and 4 are fine and
when you put a sine wave into either channel 1 or 2 and move vertical
position up down, it gets compressed vertically at top and bottom.

The only thing that I am still a little worried about is that the output
text is shifted down. Wasn’t clear from other u400 reports whether that was
a symptom or not.

Any thought whether I am guessing right on the u400?

Sounds like a reasonable guess, though without seeing the problem first
hand it’s hard to say. Maybe you could post a video for posterity and the
groups edumafication?
Note that problems in the readout switching can also affect CH1/2 and the
readout. See e.g. https://groups.io/g/TekScopes/message/117824.

Have a used one on the way and planned to put it in after doing a quick
voltage and ripple test for anything that could fry the new u400


Re: Tek 547 A Sweep display during retrace

Morris Odell
 

I’ve come late to this thread but as it happened last week I had to deal with just this problem in the B sweep of my 547. The problem was a failure of Q184, a 2N2207 that amplifies the sweep intensification pulse for the B sweep. According to the schematic that transistor runs at a Vce of 67 volts. I replaced it with a BC640, all of 95cents from the local electronics emporium. It was the only higher voltage (80V) PNP they had with Cin = 110 pf, Cout = 9.0 pf, Ft = 150 MHz. The leads needed a bit of persuasion to fit the socket but hey, you’ve got to work with what you’ve got.



I tried to autopsy the 2N2207 to see if I could see whiskers or anything else abnormal under a microscope. After decapitating it I found it was full of white pasty material resembling dried up thermal heatsink compound. I couldn’t clean it all out properly to see the innards so it went in the bin. The 547 is as good as new and still my favourite scope.



Morris







Re: Tek 547 A Sweep display during retrace
From: Dave Wise <mailto:david_wise@phoenix.com?subject=Re:%20Tek%20547%20A%20Sweep%20display%20during%20retrace>
Date: Wed, 03 Jan 2018 17:22:21 PST

BC556 + 220pF is 55ns/30ns, the same on-time as the 2N2207. The Pro-Electron C-B-E pinout makes it easier to use than KSA992.

Two more base-in-the-middle parts:
MPSA56 + 470pF is 55/30.
PN2907A + 470pF is 60/30.

And there's a laugh - the PN2907A was what I tried something like ten years ago and gave up!



---
This email has been checked for viruses by AVG.
http://www.avg.com


Re: 5440 No Trace

magnustoelle
 

Good Day,

Rick, I am glad to hear you have fixed this by replacing R410. Nice to hear that another 5440 is back to operation.

Cheers,

Magnus

On 04/01/2018 03:22, Rick wrote:
You would think after all the time you guys have spent with me on this repair I'd learn a thing or two. I should have known exactly what the consequences shunting R410, the 3.3 ohm 1/2 watt resistor to the chassis. The first thing I did was confirm it still had the 44v supply to it and saw the voltage drop across down to 10mV. That was a give away because the current draw from the short would burn open the resistor. At 3.3 ohms that 13 watts and that was clearly pointed out to me 10 messages ago. I missed it. Q400 is good. I realized there was no way that resister couldn't not be 100% open especially since it showed no sign of burns. I replaced it and bingo all works perfectly. Still in calibration. All I needed was the new HV Multiplier and a proper install. I did use several layers of heat activated glue heatshrink.

Thank you to all that chimed in. I promise I won't forget what I learned this time. The beauty is it is always something very simple if you can clear you head and listen to learn from advice.

I have several more Tek projects. I still want to fix the excessively high SG505 output and make a notch filter fixture to calibrate it. Also I have an extra AA501 I need to get working. I'll be back.

Rick


Re: Tek 2465b with down shifted display..

Chuck Harris <cfharris@...>
 

Good advice for the 500 series, the 453, 454, 455, 465, 7000, ...
scopes of that era, but the 2465 family doesn't have any discrete
transistors in the vertical amplifier signal path.

And...

The signal path connections between the various hybrid stages are
all underneath the A1 board, and as such aren't readily reachable.

-Chuck Harris

HankC, Boston, WA1HOS via Groups.Io wrote:

Mark,
I did not see your original post but, as another member suggested, one side of your vertical amp is DOA.Are both channels affected in the same way? If so, the problem is after the channel switch.
This is easily isolated by shorting opposite sides of the amplifier to each other with a short jumper.
If the trace centers up, the problem is prior to the short location.Move the short one stage towards the input until the trace no longer centers.That stage is where the problem is; in all likelihood, one of the transistors in that stage is defective.If you swap those transistors, and the problem shifts the other direction, you have found your problem.It is best to return transistors to their original sockets so you will minimize the affects on the calibration.
HankC, Boston WA1HOS


Re: Tek 2465b with down shifted display..

 

Mark,
I did not see your original post but, as another member suggested, one side of your vertical amp is DOA.Are both channels affected in the same way?  If so, the problem is after the channel switch.
This is easily isolated by shorting opposite sides of the amplifier to each other with a short jumper.
If the trace centers up, the problem is prior to the short location.Move the short one stage towards the input until the trace no longer centers.That stage is where the problem is; in all likelihood, one of the transistors in that stage is defective.If you swap those transistors, and the problem shifts the other direction, you have found your problem.It is best to return transistors to their original sockets so you will minimize the affects on the calibration.
 HankC, Boston WA1HOS


Re: 5440 No Trace

Rick
 

You would think after all the time you guys have spent with me on this repair I'd learn a thing or two. I should have known exactly what the consequences shunting R410, the 3.3 ohm 1/2 watt resistor to the chassis. The first thing I did was confirm it still had the 44v supply to it and saw the voltage drop across down to 10mV. That was a give away because the current draw from the short would burn open the resistor. At 3.3 ohms that 13 watts and that was clearly pointed out to me 10 messages ago. I missed it. Q400 is good. I realized there was no way that resister couldn't not be 100% open especially since it showed no sign of burns. I replaced it and bingo all works perfectly. Still in calibration. All I needed was the new HV Multiplier and a proper install. I did use several layers of heat activated glue heatshrink.

Thank you to all that chimed in. I promise I won't forget what I learned this time. The beauty is it is always something very simple if you can clear you head and listen to learn from advice.

I have several more Tek projects. I still want to fix the excessively high SG505 output and make a notch filter fixture to calibrate it. Also I have an extra AA501 I need to get working. I'll be back.

Rick


Re: Tek 547 A Sweep display during retrace

Dave Wise
 

BC556 + 220pF is 55ns/30ns, the same on-time as the 2N2207. The Pro-Electron C-B-E pinout makes it easier to use than KSA992.

Two more base-in-the-middle parts:
MPSA56 + 470pF is 55/30.
PN2907A + 470pF is 60/30.

And there's a laugh - the PN2907A was what I tried something like ten years ago and gave up!


Re: First draft of the Tek knob visual index project

Dano
 

On Sun, Dec 31, 2017 at 09:39 pm, Richard Knoppow wrote:

[snipped]
    I think there are some people who do not have a mail server that
Thunderbird or other mail clients can connect to. I agree its much
better to use a mail client for mailing lists and I happen to use
Thunderbird also.
[snipped]

Yes, that's precisely my issue. I have many domains with domain level rules, and no modern mobile email client can handle it correctly. Therefore, it's just much simpler to login to a webpage. I use any device that's near me or on me to read emails, but I have to wait to get to a PC in order to reply. It's a PITA, but redoing a bunch of domain rules just to make that work, isn't something I'm interested in doing right now. (can't stand typing on mobile devices anyhow, lol.)

Thanks for all the suggestions, they will help down the road!

-Dano

(some of you may remember Eudora, wonder whatever happened to them...)


Re: Tektronix PS280

Twig
 

The link from W140.com that tom jobe posted above does indeed have schematics. That is the good news. The bad news is that the schematics are riddled with errors, as I found when doing some troubleshooting a while ago. Best to take them with a grain of salt if you find something that does not make sense.


Re: First draft of the Tek knob visual index project

Dano
 

On Tue, Jan 2, 2018 at 08:55 am, tronix_cal wrote:

Are you using the Common Design Parts Catalog for any part of the project?
While it doesn't have the useable on code (Knob to Model number) listing, the
dimensions, logos, labeling, method of manufacture (molded/machined) and ID/OD
info is all there, with a directory of drawings. I know of a hard copy I
could borrow. The data could be extracted, without outright copying of the
entire content, couldn't it?
I have that manual, and am planning on scanning in the section with knobs to send to Walter. Just a FYI, in case you don't have easy access to it.

I'm still trying to find ANYONE who has more of those volumes, I'd like to get them scanned in and make them available (hopefully without stepping on toes). I realize they, either don't exist, or they do, and no one wants to part with them. Will have to figure out that hurdle, but no one has responded to my prior request, so that's the first step. Anyone willing to work with me? I have a high speed scanner, however it's only 8.5" x Unlimited, so folded pages will be tougher since they're typically 11x~17.

I have Volume 2 (1988 release), but that's it. I'd love to see those microfiche get scanned in too!

I'll start a new thread when I've got my system(s) setup better for scanning workflow. Feel free to response in the meantime though.

Cheers!

-Dano


Re: 5440 No Trace

Rick
 

Thanks for the sympathies Magnus. I will check Q400 tonight. My short at the resistor is before the fuse so it might not put any heavy current through it. Rick


Re: Tek 2465b with down shifted display..

Mark Hatch
 

Siggi

Thank you for the reply! The 2456b did arrive and it now appears to have what appears to be classical u400 failure. Channels 3 and 4 are fine and when you put a sine wave into either channel 1 or 2 and move vertical position up down, it gets compressed vertically at top and bottom.

The only thing that I am still a little worried about is that the output text is shifted down. Wasn’t clear from other u400 reports whether that was a symptom or not.

Any thought whether I am guessing right on the u400? Have a used one on the way and planned to put it in after doing a quick voltage and ripple test for anything that could fry the new u400

Thanks

Mark


Re: TDS-520

jafinch78 .
 

On Wed, Jan 3, 2018 at 12:52 pm, Artekmedia wrote:


Yes both volumes are included in that set
Great, you are correct. PDF scans with links are really a time saver.

I think the HP8640B OPT323 Air Force manuals were a great deal too I downloaded this morning (I'm nonionizingemf also). Thanks for offering the CD's at a better price too.

I'll go ahead and buy now... I can use the more accurate information. Lot's of options and issues with these boards so I mise well upgrade to better quality while I am repairing now.

Thanks DC! :-)


Re: TDS-520

Artekmedia <manuals@...>
 

Yes both volumes are included in that set

We will be here next month :-)
-DC

On 1/3/2018 3:37 PM, jafinch78 . wrote:
On Wed, Jan 3, 2018 at 12:15 pm, Artekmedia wrote:

We offer BOTH Vol1 and Vol2 of the service manual

I am curious to know where you got a copy of Vol2
Are both Vol1 and Vol2 combined with the "FULL SCHEMATICS" purchase?

I was thinking to purchase. Though trying to push off until next months budget plan.

I'm not sure where I found the Vol2. I deleted my older browsing history and found somewhere online hunting on Google for information.

Thanks in advance for your time


--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com


Re: TDS-520

Artekmedia <manuals@...>
 

That is apparently a typo in the original manual It is actually on 11-12  Upper right hand corner, (not 11-14).

Another reason to have a "text searchable" Artek Manuals scan. Although I will be the first to tell you that OCR driven text searching is not 100% infallible

-DC
manuals@artekmanuals.com

On 1/3/2018 3:35 PM, jafinch78 . wrote:
On Wed, Jan 3, 2018 at 12:15 pm, Artekmedia wrote:

There is a note on the schematic that R199 is not installed on boards with 8K
RAM and 32K RAM
I don't see the note regarding RAM, where are you finding this?

I don't see the A11-14 5A either on the schematic referring to R1998 or R1999.



--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com


Re: TDS-520

jafinch78 .
 

On Wed, Jan 3, 2018 at 12:15 pm, Artekmedia wrote:


We offer BOTH Vol1 and Vol2 of the service manual

I am curious to know where you got a copy of Vol2
Are both Vol1 and Vol2 combined with the "FULL SCHEMATICS" purchase?

I was thinking to purchase. Though trying to push off until next months budget plan.

I'm not sure where I found the Vol2. I deleted my older browsing history and found somewhere online hunting on Google for information.

Thanks in advance for your time


Re: TDS-520

jafinch78 .
 

On Wed, Jan 3, 2018 at 12:15 pm, Artekmedia wrote:


There is a note on the schematic that R199 is not installed on boards with 8K
RAM and 32K RAM
I don't see the note regarding RAM, where are you finding this?

I don't see the A11-14 5A either on the schematic referring to R1998 or R1999.


Re: TDS-520

Artekmedia <manuals@...>
 

All

I have not been following this thread closely  but here is what I see in my scan of the TDS520 service manual R1998 and R1999 are located between U12 and J2 in as shown in Vol2, Figure 9-112. at locator D4 ( there are two locator designations , one for the schematic and one for the board overlay ...I perceive that perhaps the you may have confused the two)

There is a note on the schematic that R199 is not installed on boards with 8K RAM and 32K RAM

We offer BOTH Vol1 and Vol2 of the service manual

I am curious to know where you got a copy of Vol2

Regards
-DC
manuals@artekmanuals.com

On 1/3/2018 2:31 PM, jafinch78 . wrote:
On Wed, Jan 3, 2018 at 06:31 am, Siggi wrote:

On which schematic page did you find R1999? To determine whether R1998 is a
strapping resistor, you might see whether one of the unused pads shares a
track with one end of R1999. If so, then it's likely that their purpose is
to select some kind of an alternative.
I didn't find either R1998 or R1999 on the schematic, though they were listed in the parts locator as 14, 5A. R1999 is on my board in between J2 and U12. Yes, they share a trace and pad.

Are these boards capable of 1GHz and 4GS/s like say the 744a?: https://www.eevblog.com/forum/testgear/conversion-of-500mhz-tds744a-to-1ghz-tds784a/

I did just purchase the HP8640b OPT323 Airforce manual from Artek.

Artek TDS-520 Component Level Diagnostic Repair Manual shows all the boards? I have a volume 2 with A10 thru A21. Not Volume 1 through.


--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com


Re: TDS-520

jafinch78 .
 

On Wed, Jan 3, 2018 at 06:29 am, Siggi wrote:


Yeah, a 0 Ohm resistor is essentially just a link, and here they tie an
input line on an IO register either high or low. There's a note regarding
R6-R17 on the schematic:

"VERSION ID RESISTOR PLACEMENT:
PLACE U4 AND R12-517 ONLY ON BOARDS THAT HAVE EXCEEDED THE ID NUMBER
11110XXX.
IN THIS CASE, THE VERSION NUMBER IS DECODED VIA PINS 2, 3, 4 OF U4.
R7, R9, R11 ARE NOT PLACED & PINS 5-9 OF U3 ARE WIRED HIGH."
U4 isn't present on my board. R7, R9 and R11 are placed though. I do see the note now related to version ID resistors.

I wonder if this was causing issues?

I don't see an ID number on my board. Where is this found?

42901 - 42920 of 186193