Date   

Re: Questions I have if Attachments are Permitted

Renée
 

Thanks Chuck -
I pretty much have stayed out of this as I know I am in the minority. I am one of those unknown mentioned, only in rural CA. in fact we have so many choices - one - and their service is inconsistent at best. (ok, read horrible)
 Cell service- we are lucky to have one bar ( just like the town) and that ceases when the weather get bad - rain.  many times one must find the right place to stand to make a call.   tracfone (using verizon no service from any other carriers) is the only option for inexpensive cell service and as Chuck says it is a nickle and dime ( ok a quarter to start) service.
Dial-up is a whopping 42K max when it works. so for emergency phone we rely on the one expensive choice landline.
....oh I forgot I travel to another town and use their library internet (once a week-shopping) or visit a friend down the road who has a sat connection for large files and stuff with lots of graphics. Thunderbird does a great job on limiting the size of emails!

Now the above being said, I will go with whatever the group decides. the info is just too valuable. Even the OT stuff!

Renée

On 5/21/20 8:09 AM, Chuck Harris wrote:
I can help you with that!

Everyone that lives in the large flyover country
parts of rural US.

Not only do they get their internet over the telephone lines at
typically 56Kbits per second modem rates, they get slow or no
cell service to boot.

And, everyone that relies on tracfone, and its ilk, for their cell
service. That includes a lot of seniors. Their phones cost them
6 or 7 bucks a month, but they get nickle and dimed for each minute.

Broadband exists in all of the big cities, and their suburbs. But
it doesn't exist in the large central regions of the big farm states.

It also doesn't exist in the mountain areas, like parts of WV, CO,
TN, AK... Nor does it exist in large parts of OK, MN, WI, IA, ND,
SD, WY... need I go on?

And, even if your isp doesn't charge you a data rate for its 56K bit/sec
service, a 5.6mbyte picture takes 1000 seconds to be transferred down
your slow pipe.

If that isn't a cost, I don't know what is!

-Chuck Harris


Michael W. Lynch via groups.io wrote:
Dennis,

First let me say, I am happy with whatever the Administrator and Owners of this group decide. I will adapt as needed.

I have a serious question about this and since I seem to be quite oblivious, here goes:

QUESTION #4: If almost all TekScopes members have no interest in the napkin
sketch you attached to your message why should they have to download it to
their PC and pay data charges for something they will immediately delete
once they see what the attachment is about.<<

My Question: Who pays data charges in today's world? Comments seem to indicate that many here use "metered" connections, and I simply did not realize that those were that common these days. My ISP is unlimited up and download as far as I know (Yes, I realized that download is MUCH faster than upload speeds). I have not paid data charges in decades. Keep in mind, I live in rural Arkansas, so I am not even close to the "bleeding edge" of the internet or cell coverage. I'm just happy to have relatively "High Speed" internet. This applies to my phone and home ISP. I am just asking so that I can learn. This seems to be a huge issue for many on this forum.

Please advise and educate, as you always seem to be able to do.

I appreciate all that you do and the great benefit of this forum.

Sincerely,


Re: 475 questions

Leanna L Erickson <lle@...>
 

PS capacitors

Figure on replacing some of the full wave bridge rectifier, cut them out.
Use a Weller old style soldering gun.
Use solder wick or sucker to remove a lot of solder, gently and forcibly use a forceps or similar device and pull, rocking back and forth.
Note the connectivity of associated traces. You have to maintain continuity of the ground lug connection.
Replacement of cans will use something other than the cans, you may need to be creative.

Same routine appies to the 465.

Keith

On May 21, 2020, at 9:26 AM, ciclista41 via groups.io <ciclista41=yahoo.com@groups.io> wrote:

Thanks Keith! I'd like to get a hard copy if I'm keeping the scope, but if I discover it's beyond worth reviving, I don't want to make the investment It's encouraging to hear that you've brought back several! Sounds as if you actually did replace those big caps without removing the board. I'd like to know how to do that, unless it's more trouble that removing the board to do it!



Re: Questions I have if Attachments are Permitted

Michael W. Lynch
 

Chuck,

Thanks for enlightening me! Like I said, I "assumed" that I lived in about as "flyover" an area as possible. Perhaps I am not as backward here in the hills of Arkansas as I had "assumed"? Thus my perception of the issue being discussed.

Thankfully, I have 20Mb/sec down and 1.2Mb/Sec upload (using a DSL connection) over phone lines, but almost no cell service (due to being located in a valley), so Wi-Fi assist is my go to at home. With my physical location, service provider is irrelevant, no one has "good" cell service in this immediate area. I do not use Trac-phone or other such "budget" providers, they just do not meet my needs, besides, being "nickle and dimed" just forces my blood pressure up.

Please understand, I am not lobbying for or against these attachments, just trying to understand the conversation and the objections of others.

Thanks Again!

--
Michael Lynch
Dardanelle, Arkansas


Re: Questions I have if Attachments are Permitted

Chuck Harris <cfharris@...>
 

I can help you with that!

Everyone that lives in the large flyover country
parts of rural US.

Not only do they get their internet over the telephone lines at
typically 56Kbits per second modem rates, they get slow or no
cell service to boot.

And, everyone that relies on tracfone, and its ilk, for their cell
service. That includes a lot of seniors. Their phones cost them
6 or 7 bucks a month, but they get nickle and dimed for each minute.

Broadband exists in all of the big cities, and their suburbs. But
it doesn't exist in the large central regions of the big farm states.

It also doesn't exist in the mountain areas, like parts of WV, CO,
TN, AK... Nor does it exist in large parts of OK, MN, WI, IA, ND,
SD, WY... need I go on?

And, even if your isp doesn't charge you a data rate for its 56K bit/sec
service, a 5.6mbyte picture takes 1000 seconds to be transferred down
your slow pipe.

If that isn't a cost, I don't know what is!

-Chuck Harris


Michael W. Lynch via groups.io wrote:

Dennis,

First let me say, I am happy with whatever the Administrator and Owners of this group decide. I will adapt as needed.

I have a serious question about this and since I seem to be quite oblivious, here goes:

QUESTION #4: If almost all TekScopes members have no interest in the napkin
sketch you attached to your message why should they have to download it to
their PC and pay data charges for something they will immediately delete
once they see what the attachment is about.<<

My Question: Who pays data charges in today's world? Comments seem to indicate that many here use "metered" connections, and I simply did not realize that those were that common these days. My ISP is unlimited up and download as far as I know (Yes, I realized that download is MUCH faster than upload speeds). I have not paid data charges in decades. Keep in mind, I live in rural Arkansas, so I am not even close to the "bleeding edge" of the internet or cell coverage. I'm just happy to have relatively "High Speed" internet. This applies to my phone and home ISP. I am just asking so that I can learn. This seems to be a huge issue for many on this forum.

Please advise and educate, as you always seem to be able to do.

I appreciate all that you do and the great benefit of this forum.

Sincerely,


Re: Questions I have if Attachments are Permitted

Michael W. Lynch
 

Dennis,

First let me say, I am happy with whatever the Administrator and Owners of this group decide. I will adapt as needed.

I have a serious question about this and since I seem to be quite oblivious, here goes:

QUESTION #4: If almost all TekScopes members have no interest in the napkin
sketch you attached to your message why should they have to download it to
their PC and pay data charges for something they will immediately delete
once they see what the attachment is about.<<

My Question: Who pays data charges in today's world? Comments seem to indicate that many here use "metered" connections, and I simply did not realize that those were that common these days. My ISP is unlimited up and download as far as I know (Yes, I realized that download is MUCH faster than upload speeds). I have not paid data charges in decades. Keep in mind, I live in rural Arkansas, so I am not even close to the "bleeding edge" of the internet or cell coverage. I'm just happy to have relatively "High Speed" internet. This applies to my phone and home ISP. I am just asking so that I can learn. This seems to be a huge issue for many on this forum.

Please advise and educate, as you always seem to be able to do.

I appreciate all that you do and the great benefit of this forum.

Sincerely,

--
Michael Lynch
Dardanelle, Arkansas


Re: 475 questions

ciclista41@...
 

Thanks Keith! I'd like to get a hard copy if I'm keeping the scope, but if I discover it's beyond worth reviving, I don't want to make the investment. It's encouraging to hear that you've brought back several! Sounds as if you actually did replace those big caps without removing the board. I'd like to know how to do that, unless it's more trouble that removing the board to do it!


Re: 475 questions

ciclista41@...
 

Thanks for the helpful reply, Reed!

Do you think it's safe to turn the scope on with all those test points showing as shorted? I don't want to destroy anything more than already possibly has been, and in my admittedly limited experience, a short means things go POP! I'm going to put a 100 watt incandescent light bulb in series with the hot line of my electrical receptacle as a voltage limiter to reduce the likelihood of frying anything in the few seconds it will take to do the measurements as you suggest.

I like the idea of using the 200 μF capacitor to see if it resolves some problems...or are you suggesting adding them in parallel with the filter caps that are so inaccessible as a permanent fix?


Re: 475 questions

Leanna L Erickson <lle@...>
 

Test points

Equipment must be energized.

PS caps
Can be a bear to replace without removing board. Been there, done that.

A hard copy of SM works out best.

Good Luck,

Keith, Wayzata, MN
I have brought back several.

On May 20, 2020, at 11:53 PM, ciclista41 via groups.io <ciclista41=yahoo.com@groups.io> wrote:

Hi, all! First post here. As I'm sure will soon become obvious, I am new to electronics, though I have completed a few minor repairs and projects over the years. I have never used an oscilloscope. I am retired, and have lots of time to pursue this new hobby. I just bought a couple of non-working (according to the seller) scopes--a Philips PM 3218 (irrelevant, I know) and a Tektronix 475 Mod. OS261C Opt. 4, 7 Ser.#B287863. I say according to the seller, because I have been afraid to power up the 475 until I know more about it and its condition. I don't think the seller had had it on for quite some while, either. My research so far has told me that the 475 is the one perhaps more worth bringing back to life. I haven't read every post referencing the 475, but I have read a LOT of them. Also, I have the 070-1832-00 Tektronix 475 Service Instruction Manual in .pdf. Anyway, here are some questions that I hope one or some of you will be able and willing to help me out by answering:

Why are there three power settings on the back by the fuse that overlap? I measure ~ 118V at my wall receptacle, so it appears that any of the settings will work equally well.

Someone posted that the test point ohm readings should be the following (my repeated results with two different analog meters follow in parentheses):

(test point = expected ohm reading)

110 = 11K (18 climbing from < 10)

50 = 2.7K (2.7)

15 = 63 (0)

5 = 46 (0)

-15 = 480 (19)

-8 = 32 (0)

UNREG 50 = 14K (7.5)

105 = 12K (16 rising from < 10) no test post found to match the others, but I was able to find the trace with that label and take a reading from its junction with a large cap lead.

It would appear that there is so much wrong based on these readings that maybe the $20 I paid was no bargain. However, I once diagnosed a Peugeot 504 Diesel electrical problem that was extensive and affected almost every electrical circuit. I found one melted trace in the instrument panel that, once bridged with a short piece of wire, solved every electrical problem in the vehicle. So, I remain optimistic that perhaps a single capacitor (or a few) might correct much of this. On the other hand, I've also read that some key parts may no longer be available, and if it needs a new CRT, I'd guess it's a lost cause. What would anyone else surmise from these readings? Where did the expected readings come from? I found no such reference in my manual.

Neither glass fuse that I found was blown, but under the aluminum "Warning High Voltage" panel, there was evidence of magic smoke having been emitted onto the white Sprague capacitors and the two glass neon bulbs DS1382 and DS1383. What the heck are those for under a panel? Those items, themselves, do not visually appear to be damaged. I see no other components that appear to be the source of the smoke, either, though.

How does one access the large electrolytic capacitors? They are measurable from the bottom of the board, because they rise from that upward, sandwiched between the bottom and top boards and between the right board and the CRT. My manual provides directions for board removal, but as others have said, it is no easy process. I'm hoping there's a shortcut. Unfortunately, my ESR meter does not measure capacitors with such a high capacitance rating. Also, it does not measure capacitors with such a low capacitance rating as those Spragues under the HV panel.

I've read over and over that the tantalum caps should be replaced, but nearly all those I can read show themselves to be within spec. when read in-circuit with my ESR meter. Do I need to tear this whole thing apart to replace all the questionable caps? I'm mechanically inclined, so I'm not necessarily averse to it if so.

Finally, I just read that there are white dummy resistors (I count six that appear to meet this description) that can be unsoldered to isolate portions of the board so as to facilitate diagnosis. Where can I find more information about these?

Thank you very much in advance!

Bruce



Re: 475 questions

Reed Dickinson
 

Hi Bruce:
I have found that resistance checks are not a good measure of the reliability of any instrument.  Here is what I would do.  Get a DC voltmeter turned on, connect the ground lead to the chassis and put your hot lead on the +50 TP and turn the scope on.  Look immediately at the voltmeter if it says 50V great, power off immediately.  Next move your probe to the next lower voltage and repeat test, continue until all the low voltages have been tested.  Next turn the intensity up and look for a beam or light on the screen,  If you see a crazy collection of lines on the CRT you probably have an open filter cap in the low voltage circuit.  Try putting a 200uF cap from the center terminal to ground of each filter cap.  What ever you do DO NOT REMOVE THE MOTHER BOARD.  It is a pure PITA to get out and even worse to get back in.  Good luck!
Reed Dickinsonreed714@sbcglobal.net

On Wednesday, May 20, 2020, 09:53:20 PM PDT, ciclista41 via groups.io <ciclista41=yahoo.com@groups.io> wrote:

Hi, all!  First post here.  As I'm sure will soon become obvious, I am new to electronics, though I have completed a few minor repairs and projects over the years.  I have never used an oscilloscope.  I am retired, and have lots of time to pursue this new hobby.  I just bought a couple of non-working (according to the seller) scopes--a Philips PM 3218 (irrelevant, I know) and a Tektronix 475 Mod. OS261C Opt. 4, 7 Ser.#B287863.  I say according to the seller, because I have been afraid to power up the 475 until I know more about it and its condition.  I don't think the seller had had it on for quite some while, either.  My research so far has told me that the 475 is the one perhaps more worth bringing back to life.  I haven't read every post referencing the 475, but I have read a LOT of them. Also, I have the 070-1832-00 Tektronix 475 Service Instruction Manual in .pdf. Anyway, here are some questions that I hope one or some of you will be able and willing to help me out by answering:

Why are there three power settings on the back by the fuse that overlap?  I measure ~ 118V at my wall receptacle, so it appears that any of the settings will work equally well.

Someone posted that the test point ohm readings should be the following (my repeated results with two different analog meters follow in parentheses):

(test point = expected ohm reading)

110 = 11K (18 climbing from < 10)

50 = 2.7K (2.7)

15 = 63    (0)

5 = 46    (0)

-15 = 480  (19)

-8 = 32  (0)

UNREG 50 = 14K  (7.5)

105 = 12K  (16 rising from < 10) no test post found to match the others, but I was able to find the trace with that label and take a reading from its junction with a large cap lead.

It would appear that there is so much wrong based on these readings that maybe the $20 I paid was no bargain.  However, I once diagnosed a Peugeot 504 Diesel electrical problem that was extensive and affected almost every electrical circuit.  I found one melted trace in the instrument panel that, once bridged with a short piece of wire, solved every electrical problem in the vehicle.  So, I remain optimistic that perhaps a single capacitor (or a few) might correct much of this.  On the other hand, I've also read that some key parts may no longer be available, and if it needs a new CRT, I'd guess it's a lost cause.  What would anyone else surmise from these readings?  Where did the expected readings come from?  I found no such reference in my manual.

Neither glass fuse that I found was blown, but under the aluminum "Warning High Voltage" panel, there was evidence of magic smoke having been emitted onto the white Sprague capacitors and the two glass neon bulbs DS1382 and DS1383.  What the heck are those for under a panel?  Those items, themselves, do not visually appear to be damaged.  I see no other components that appear to be the source of the smoke, either, though.

How does one access the large electrolytic capacitors?  They are measurable from the bottom of the board, because they rise from that upward, sandwiched between the bottom and top boards and between the right board and the CRT.  My manual provides directions for board removal, but as others have said, it is no easy process.  I'm hoping there's a shortcut.  Unfortunately, my ESR meter does not measure capacitors with such a high capacitance rating.  Also, it does not measure capacitors with such a low capacitance rating as those Spragues under the HV panel.

I've read over and over that the tantalum caps should be replaced, but nearly all those I can read show themselves to be within spec. when read in-circuit with my ESR meter.  Do I need to tear this whole thing apart to replace all the questionable caps?  I'm mechanically inclined, so I'm not necessarily averse to it if so.

Finally, I just read that there are white dummy resistors (I count six that appear to meet this description) that can be unsoldered to isolate portions of the board so as to facilitate diagnosis.  Where can I find more information about these?

Thank you very much in advance!

Bruce


475 questions

ciclista41@...
 

Hi, all! First post here. As I'm sure will soon become obvious, I am new to electronics, though I have completed a few minor repairs and projects over the years. I have never used an oscilloscope. I am retired, and have lots of time to pursue this new hobby. I just bought a couple of non-working (according to the seller) scopes--a Philips PM 3218 (irrelevant, I know) and a Tektronix 475 Mod. OS261C Opt. 4, 7 Ser.#B287863. I say according to the seller, because I have been afraid to power up the 475 until I know more about it and its condition. I don't think the seller had had it on for quite some while, either. My research so far has told me that the 475 is the one perhaps more worth bringing back to life. I haven't read every post referencing the 475, but I have read a LOT of them. Also, I have the 070-1832-00 Tektronix 475 Service Instruction Manual in .pdf. Anyway, here are some questions that I hope one or some of you will be able and willing to help me out by answering:

Why are there three power settings on the back by the fuse that overlap? I measure ~ 118V at my wall receptacle, so it appears that any of the settings will work equally well.

Someone posted that the test point ohm readings should be the following (my repeated results with two different analog meters follow in parentheses):

(test point = expected ohm reading)

110 = 11K (18 climbing from < 10)

50 = 2.7K (2.7)

15 = 63 (0)

5 = 46 (0)

-15 = 480 (19)

-8 = 32 (0)

UNREG 50 = 14K (7.5)

105 = 12K (16 rising from < 10) no test post found to match the others, but I was able to find the trace with that label and take a reading from its junction with a large cap lead.

It would appear that there is so much wrong based on these readings that maybe the $20 I paid was no bargain. However, I once diagnosed a Peugeot 504 Diesel electrical problem that was extensive and affected almost every electrical circuit. I found one melted trace in the instrument panel that, once bridged with a short piece of wire, solved every electrical problem in the vehicle. So, I remain optimistic that perhaps a single capacitor (or a few) might correct much of this. On the other hand, I've also read that some key parts may no longer be available, and if it needs a new CRT, I'd guess it's a lost cause. What would anyone else surmise from these readings? Where did the expected readings come from? I found no such reference in my manual.

Neither glass fuse that I found was blown, but under the aluminum "Warning High Voltage" panel, there was evidence of magic smoke having been emitted onto the white Sprague capacitors and the two glass neon bulbs DS1382 and DS1383. What the heck are those for under a panel? Those items, themselves, do not visually appear to be damaged. I see no other components that appear to be the source of the smoke, either, though.

How does one access the large electrolytic capacitors? They are measurable from the bottom of the board, because they rise from that upward, sandwiched between the bottom and top boards and between the right board and the CRT. My manual provides directions for board removal, but as others have said, it is no easy process. I'm hoping there's a shortcut. Unfortunately, my ESR meter does not measure capacitors with such a high capacitance rating. Also, it does not measure capacitors with such a low capacitance rating as those Spragues under the HV panel.

I've read over and over that the tantalum caps should be replaced, but nearly all those I can read show themselves to be within spec. when read in-circuit with my ESR meter. Do I need to tear this whole thing apart to replace all the questionable caps? I'm mechanically inclined, so I'm not necessarily averse to it if so.

Finally, I just read that there are white dummy resistors (I count six that appear to meet this description) that can be unsoldered to isolate portions of the board so as to facilitate diagnosis. Where can I find more information about these?

Thank you very much in advance!

Bruce


Questions I have if Attachments are Permitted

 

I have no personal preference for or against attachments.
I do think it should be a requirement that "Attachments must, above all
else, do no harm."
From what I have learned so far I have a few unanswered questions that must
be resolved before I can make a decision.

These are my first three unanswered questions. I will add a 4th question
after I explain how an email program works.
QUESTION #1: Are the benefits to those who want attachments greater than
drawbacks they impose on everyone else? Read the section below titled "How
Internet Mail Programs Work" first before you answer this question

QUESTION #2: The posts that include attachments will not go through to
TekScopes until the attachments can be opened and checked for size,
relevance, and viruses at a minimum. How long are you willing to wait for
your poat to be checked and accepted? What should be done if your time limit
comes and goes without checking your attachment?

QUESTION #3: Who has the time to check the email with attachments? No one
has offered me an answer so far.

How Internet Mail Programs Work
This is my understanding of how internet mail protocols work to accept a
mail from one member and send it to all our members:
* When you attach a napkin sketch to your email and press send the Simple
Mail Transfer Protocol (SMTP) takes charge to insure it gets to your
destination.
* The initial destination is a mail server run by Groups.io that maintains
the TekScopes mailbox.
* Groups.io maintains a list of TekScopes' member email addresses, their
delivery preferences, and (if attachments are permitted) their Max
Attachment Size preference.
* For the members who set their delivery preferences to "Individual
Messages" and their "Max Attachment Size" to larger than the attachment,
Groups.io will send the email and the attachment to the mail server the
member's email account is on.
* This will result in the original email and its attachment going to
thousands of email addresses.
* Each of the thousands of member's mail servers will store the message and
the attachment until the next time the member connects to their server to
retrieve all of the email messages and attachments waiting for them.
* When you tell your mail program to download your mail it starts sending
all of it to your PC.
* Think about the last time you received a large attachment in an email. If
you have a very poor or intermittent connection you might have no choice but
to reconnect several times to receive an entire large attachment.
* Recall how long it took to download an entire large attachment to your PC.
That is because all of the data in the attachment is now on your hard disk.
You paid for the data to go from your ISP to your PC. Notice that if you
click on the attachment with your mouse it opens immediately. That is proof
that it is on your hard disk. This is the basis for my next question:

Please read the nine bullet points above before answering this next
question.
QUESTION #4: If almost all TekScopes members have no interest in the napkin
sketch you attached to your message why should they have to download it to
their PC and pay data charges for something they will immediately delete
once they see what the attachment is about.

If you have solutions for my four questions please contact me off list using
this address
dennis at ridesoft dot com
Change the subject to "Solutions" or "Answers".
Please answer all four questions as succinctly as possible.

Dennis Tillman W7pf


Re: Tektronix 2782/2784 Schematics

Jim Ford
 

I can vouch for FedEx Office scanning schematics for a reasonable price.   A couple years ago I had them scan some Stanford Research Systems SR780 schematics in 11 by 17 format.  Only cost me about $20 USD.Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: spam4pauld@gmail.com Date: 5/19/20 6:17 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Tektronix 2782/2784 Schematics Take the paper schematics 8-1/2 x 11 and 11 x 17 to a Fedex/Kinkos or Staples and have them scan them for you. They can do large format with no problems, it's fast and cheap. They'll copy the PDF's to a thumb drive and you're good to go.


Re: Tektronix 2782/2784 Schematics

David DiGiacomo
 

Another option is to contact our esteemed member Dave Henderson
(ArtekManuals). He will scan the schematics for you, and give you a
credit for 2 other manuals. Pretty good deal.

http://artekmanuals.com/need-list/


Re: what is this

 

Hi David,
You have surprised me and educated me for the second time today.

In my original email I said I had a carrying case for a single TM500 plugin. What you show on your web site:
http://www.davmar.org/images/TE/Tek437-0106-00.jpg
is what I thought was my TM500 carrying case because it was much shorter than the other two carrying cases (which added 3" to 4" to the length).

Obviously as you pointed out, it is for 7000 plugins. It must have a limited purpose since it is not a carrying case and it can't power a plugin. That makes it only useful for protecting a 7M11 Dual Delay Line while it is being used since A 7M11 does not require power and does not need to use up a valuable slot to perform its function.
Mark Pilant confirmed that TekWiki says it is for the 7M11.
Dave Casey explained why it has no cover and that there is a rackmount 6 wide unit that can store 6 plugins.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David DiGiacomo
Sent: Tuesday, May 19, 2020 10:54 AM
To: TekScopes <TekScopes@groups.io>
Subject: Re: [TekScopes] what is this

On Tue, May 19, 2020 at 10:58 AM Dennis Tillman W7pF <dennis@ridesoft.com> wrote:
Thanks for pointing out that the 7000 series 2 wide and 3 wide Carrying Cases are listed in the 1985 catalog.
I never would have found them without your help for lots of reasons: there is no picture of them; they are buried on the very last page of the catalog; and there are hundreds of other things listed on this page in tiny print.
It appears Tek didn't make a single wide carrying case for the 7000 series. This explains why I have never found one.
How about the 437-0106-00?

http://www.davmar.org/images/TE/Tek437-0106-00.jpg





--
Dennis Tillman W7PF
TekScopes Moderator


Re: Understanding drawings done using text characters

Ralph Hartwell
 

All that for a simple schematic that caused more trouble than I ever intended.

-Chuck Harris

No good deed goes unpunished...


Re: Tektronix 2782/2784 Schematics

WB6GHK
 

Take the paper schematics 8-1/2 x 11 and 11 x 17 to a Fedex/Kinkos or Staples and have them scan them for you. They can do large format with no problems, it's fast and cheap. They'll copy the PDF's to a thumb drive and you're good to go.


Re: New ESR meter Group on Groups.io

Richard Knoppow
 

Well, CONUS leaves off Alaska and Hawaii and Porto Rico. Would also leave out Canada. Are you in Alaska or Canada? I used to hear "Available only in the continental United States tacked onto radio commercials.

On 5/20/2020 11:13 AM, Roy Thistle wrote:
Hi Richard:
Apologies to have been a bit cryptic... if the name got interpreted that way.
My original post to this group, about "ESR-Meters-North" somewhat explains it... I thought.
But to elaborate: the choice of the suffix "North" comes down to at least two things.
1) For years I got: "Are you in CONUS?" ... "Sorry, you are not in CONUS." ... "Only available in CONUS." Well, I finally figured out that I am not in CONUS; I'm in the NORTH. So that kind of explains it.
2) Just so that someone could start a list with world-wide subscribers, called "ESR-Meters"... and so that they could send out messages with phrases like "Sorry you are not in CONUS,"
Best regards and wishes all.
Roy

--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL


Re: New ESR meter Group on Groups.io

Roy Thistle
 

Hi Richard:
Apologies to have been a bit cryptic... if the name got interpreted that way.
My original post to this group, about "ESR-Meters-North" somewhat explains it... I thought.
But to elaborate: the choice of the suffix "North" comes down to at least two things.
1) For years I got: "Are you in CONUS?" ... "Sorry, you are not in CONUS." ... "Only available in CONUS." Well, I finally figured out that I am not in CONUS; I'm in the NORTH. So that kind of explains it.
2) Just so that someone could start a list with world-wide subscribers, called "ESR-Meters"... and so that they could send out messages with phrases like "Sorry you are not in CONUS,"
Best regards and wishes all.
Roy


Re: Readout pulsing at timebase rate

John Parkins G8KVP
 

Hello Albert,

Firstly I'm now thinking the 'ghosting' was a product of other
problems that I've now found along, maybe, with the pulsing readout.

As for the readout, yes if you had set a 1 sec timebase what happened
on the screen was that the readout would flash and the trace would
start across the screen as so on. With a fast timebase the flash
wasn't noticed.

Although I checked the voltages, which were all fine, the ripple
wasn't. I also found the standard leaking caps on the A5 board. So at
the moment the scope is in pieces having those looked at as well as
the Dallas chip. 1991 is the date on that so I thought while I was
inside the thing I'd get that sorted as well.

Once I have that done I'll see if the original problem is still there.

Thanks for the reply

Yes attachments would be useful, if you don't want them, turn them
off.

Tuesday, May 19, 2020, 8:15:08 PM, you wrote:

AO> John,

AO> It's a pity that we only have your description of ghosting here
AO> and in your previous messages (because attachments are not
AO> allowed). I think you will receive more responses if you make the
AO> picture available, for instance by placing it in the Photos
AO> section. "Interferes" with the trace is rather vague. Is there a
AO> ghost image at the trace and going up/down together with the trace position?
AO> Pulsing at the same rate as the sweep is not the same as showing
AO> ghost images. Thinking of Ernestos response, does pulsing mean
AO> that the trace and the readout(s) are displayed alternating?
AO> [BTW I'm not really familiar with this "modern" type of readout, so I probably can't help you.]

AO> Albert

AO> On Tue, May 19, 2020 at 07:55 AM, John Parkins G8KVP wrote:


Hi All.

Turns out my ghosting of the readout onto the trace is more involved
than I thought.

My 200Mhz 2445B (serial B062351) has a problem with the readout
display. It is pulsing at the same rate as the timebase sweep. At high
frequencies of course this isn't a problem but at lower speeds it gets
a bit annoying. I have the service manual and I have some idea where
to start looking but just wondered if anyone had seen this before and
could help out.

The only error I get is TEST 02 FAIL 53 not at startup but if I go
into the diagnostics. As far as I can see though this tells me I have
a stuck Delta t button, but that doesn't seem to be the case. I have
checked all the voltages and they are all spot on.
AO>




--
Best regards,
John mailto:john@g8kvp.com


Re: 7854 Bad display board

Dan G
 

On Mon, May 18, 2020 at 08:03 PM, Paul wrote:

I was clocking on the 3rd or 4th phase, as those are what's on the edge
connector
Hi Paul,

I recommend taking a look at the "TMS 9900 Memory Bus Timing"
diagram in the TMS 9900 Microprocessor Data Manual, if you
haven't seen it already. It should give you an idea of what CPU signals
you need to acquire with your LA, and how to interpret them.

I don't have the 338 LA, but it appears to have 32 channels, based on
its User's Manual. For initial diagnostics, I think you only need to monitor
the 15 address lines, plus _MEMEN, IAQ, WAIT, HOLDA, DBIN, _WE,
READY and _RESET. You can use whatever channels remain to get a
partial view of the data lines. While not perfect, that should be sufficient
for this task.

BTW, is there a program listing or disassembly somewhere that you were
referring to, or are you just intimately familiar with this beast?
There is no published firmware source code that I am aware of. I have
a side pet project that may change this in the future, but there is no
timeline yet. For now, let's just say that I happen to be familiar with portions
of the 7854 firmware that your scope does not seem to be able to get through.


dan

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