Date   
Re: 2465B battery

Bob Koller
 

The 24x5(no suffix) instruments do not have a battery, they use an EAROM chip.

Re: 2465B battery

Chuck Harris
 

If you have a real 2465 DMS, no, it uses an EAROM.

If you have a 2465A DMS, or a 2465B DMS, it has either
a LTC-7P cell, or a Dallas NVRAM.

All you have to do is look at the right side of the
scope, where the A5 controller card lives. You will
either see a Dallas NVRAM in its large black epoxy
DIP package, or you will see a battery in a large black
plastic DIP package... or, if a 2465, you will see nothing.

-Chuck Harris

Tony Fleming wrote:

Does mine 2465DMS have also a battery? Where is it? Thanks.

On Fri, May 31, 2019 at 11:23 AM Bob Koller via Groups.Io <testtech=
yahoo.com@groups.io> wrote:

You are correct, that the SMD control boards B05+, have the Dallas chip.
The earlier boards, and the 2465A, use a Keeper LTC-7P battery. These are
virtually never bad, I don't think I have had to replace more than one or
two, in the many dozens of scope I have repaired over the years. You can of
course replace if you want, but would loose the cal constants unless you
tag another battery with current limit resistor across whilst swapping. I
have done this many times with other instruments.





Re: Clock error on TDS3034

Harvey White
 

On 5/31/2019 11:35 AM, Bob Koller via Groups.Io wrote:
There are also generic LED strips available where you can trim to length, within a 3-LED pitch, as the electrical configuration is 3 LED's in series, with each triplet in parallel.
I have used these to replace the CCFL in several LCD modules. They come with a small inverter that provides intensity control.
If those are the same that I have seen, the LEDs are about 1 inch apart.  The strips are about half an inch wide.  The strips that I have used are about 1/8 inch wide, take up about 3/16 in depth and have six or seven LEDs on the front, and the same number of SMT 1206 resistors on the back.  The LEDS are 1/2 inch or less apart. That may be a requirement dependent on the diffuser that the display manufacturer.

For this design, I opted for lower voltage so this runs from +4 to +5 depending on the series resistors and the design current for the LEDS.

What they do for a commercial replacement is another matter, I don't know.  Mine are designed to fit in the same (roughly) physical space as the original CCFL lamp.

Looks as if the CCFL lamps that you replaced have a much larger size.

Harvey



Re: Clock error on TDS3034

Bob Koller
 

The strips I have are 5mm pitch LED, and 2mm wide. Obtained, as I recall on eBay as CCFL cut-to-length retrofit strips.

Re: TDS744 not 'A' has a problem , help needed

Brian
 

Hi Stephen ,
I'm pleased to hear it can all be done manually and it will be great to know how you get on with the calibration and to know your setup . When I know that I can check my gear and see if I can match the spec where its needed - for frequency accuracy if needed I have counters operating up to 40GHz should I need to use a sig gen thats not one of the synthesized ones .
Brian

On Friday, 31 May 2019, 01:32:32 BST, Stephen Hanselman <kc4sw.io@...> wrote:

Brian,

I have a 540 waiting for me after the 8566 and 8662.  Yes the process can be done manually. It’s sort of amusing that they imply automatic, but their equipment call out is all manual.

I’ll try and get my system up on Friday and get the configurations I use

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.
On May 30, 2019, at 14:29, Brian via Groups.Io <brianas1948=yahoo.co.uk@groups.io> wrote:

Hi Steve , how strange it needs the info in both places , I'll make notes so I dont forget that . I do have extended memory cards for the old PC's but I think I am likely to use windows 95/98 when I get around to doing this and then I'm sure it can use virtual memory on the hard disk if there is not enough main memory - I still have copies of s/w like ramdoubler if things get desperate .I have copies of the cal s/w from a guy on EEblog who put up the files for 500,600,700 series scopes , I have not run them yet so I hope there are no problems .Can the whole process be done manually as I am more likely to try that because the instruments I have are almost certainly not compatible with the GPIB cal s/w , some do not have a GPIB port at all .
Its good to speak to someone who has done it as it makes it feel so much more possible for me to do it
Brian

    On Thursday, 30 May 2019, 21:58:02 BST, Stephen Hanselman <kc4sw.io@...> wrote:

I suspect you have a better shot at it than I did.  One other thing when setting up the PC set files and buffers up a good bit also add some more memory above the base 640K.  also the config file for the cal software has a line that alleges to define the place it looks for the HPIB card.  It has two possible "places", I'll look later, and you need to put the card info into both of them.  This even happened on my Tek DM system.


Have you got the cal program files?

steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Brian via Groups.Io
Sent: Thursday, May 30, 2019 1:06 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] TDS744 not 'A' has a problem , help needed

Hi Steve , thank you for that . I have heard several ideas about the NVRAM contents , one is said to hold just saved waveforms and setups and the other holding cal data and installed options , cant remember which is said to do what so I'll need to search EEblog again . I have heard it said also that there are a couple of NVRAM chips underneath the acquisition pcb , little 8 pin chips , that hold factory cal data but that it is only a copy of one of the Dallas chips and is there for emergency's for use at a cal center , those 2 chips are there even on my non A version . The same source if I remember correctly said that the system does not actually use this data it relies on the Dallas chip .
I have a Fluke DC calibrator and 6.5,7.5 and 8.5 digit DVM's. Signal generators , I have synthesized gen's up to 18GHz but their output is too low , but I do have a couple of small  1MHz - 5GHz amps with output up to 20dBm that might make it possible . the final output will not be levelled directly but the input will be , to make certain I do have HP438A power meter and sensors , I also have a RACAL true RMS voltmeter that is good to 2GHz .Unlike some here I do have several old PC's with windows 95/98 could even run windows 3.11 , I have also the NI PC2A GPIB cards and drivers and a copy of the cal s/w

I am in the UK if you hadnt guessed so I think we are more than just a few miles apart or I would be happy to join you for that after school project Brian

    On Thursday, 30 May 2019, 20:32:31 BST, Stephen Hanselman <kc4sw.io@...> wrote:

I've heard the talk flow both ways but to my knowledge the calibration data is held in NVRAM on the Acquisition pca not in the Proc.  I've looked in several of the Dallas Chips and mostly what you see is empty space.  I suspect, but have no proof, that these things are used to store trace data.  I have taken non-working (fails SPC etc) and swapped in working calibrated Acq and had it remember it's calibration data.

Calibration requirements are actually fairly lax.  You need a good, accurate DC source, DMM, and after that almost any reasonable sig gen would work.  I have SG503 and SG504 the scope tells you if the particular signal you are looking at from the "SG's" is correct and then goes off and calibrates itself.  The initial DC calibrations are critical  however.  The las thing is a HPIB based controller to run the test suite.  I tried several incarnations and finally bought a Tek Data Manager.  Given no experience and all manual TE I would plan on a full day for the cal, and be prepared to become extremely bored.

If you look at your diagnostics screen where it shows SPC, Voltage ref, Frequency...... there are 4 states Initialized (after cold start), running, passed, failing.  I found out the hard way that even when you pass the CVR testing voltage ref may say "running"  although not next in the sequence you have to run probe comp to get it to read "passing"  there are a few other gotchas in the software similar to this.

If you were close by I'd tell you to bring it in as an afterschool project, but...

Hope this helps you a bit.  Like they say though, your mileage may vary

steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Brian via Groups.Io
Sent: Thursday, May 30, 2019 8:19 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] TDS744 not 'A' has a problem , help needed

Hi Stephen , fortunately the scope remembers the date and the clock is running fine . I have NVRAM back-up s/w from EEBLOG so hopefully it will keep a record of the contents assuming it works on the much older scopes but I cant see why it shouldnt . I do have some GPIB experience and enough gear to connect to the scope .The scope does have nice options for me 13,1f,2f,2m so I dont really want to loose any of themThe Dallas chips are DS1650Y and DS1486 , I understand that one of them holds calibration data - I dont know that even with the gear I have a complete recalibration would be possible so I need to keep that info as intact as possible for as long as I can . Any calibration equipment that I dont currently have will take time to get hold of as I am retired and only a hobbyist/collector .

    On Thursday, 30 May 2019, 16:03:41 BST, Stephen Hanselman <kc4sw.io@...> wrote:

Brian,

Changing out these chips is not really a problem. While they do keep some scope specific info I’ve operated 540A’s without the chip.  If you have a vanilla model, no options I’m not sure it’s worth the effort.  EBay, yes I know, has some replacements, when you look at the offerings look for one that has a “+” in the part number. So it seems like these are newer ones. The Tek forum has a thread that gives the cross wiring needed to program the Dallas chip in a more common NVRAM environment.

On the other hand if your scope remembers the date and time the chip is probably ok, for a while.

My technique is to add fresh solder to each pin and then heat the pin, not the board, and suck it out.  I then insert a socket.  So far I have not had an issue with losing data in the chip.

As it stands I have good images for the 540, 540A, and 540B.

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.
On May 30, 2019, at 07:53, Brian via Groups.Io <brianas1948=yahoo.co.uk@groups.io> wrote:

Hi Bob , thank you . That was only the second one of those scopes I've had anything to do with , I am mostly 500 series + 661 and 564 along with 7000 series and 24XX .  My first one was a TDS420A with a dead PSU , changing the caps revived it , nothing else was wrong with it . The TDS744 was also one that did not start up , after sorting out the PSU the other faults showed themselves , it was the first time fixing a component level fault on an acquisition pcb . I now have to do something about the Dallas chips they are dated '93!!

    On Thursday, 30 May 2019, 15:26:46 BST, Bob Koller via Groups.Io <testtech=yahoo.com@groups.io> wrote:

Well done!



















Re: TDS744 not 'A' has a problem , help needed

satbeginner
 

Hi, I have a TDS540B that I repaired, and somewhere down the line I would like to calibrate that too.

So I'm also interested in the manual calibration process :-)

I have a collection of marker and frequency generators, also some GPS controlled ones.

Looking forward to your progress,

Un saludo,

Leo

Re: TDS744 not 'A' has a problem , help needed

Brian
 

Hi Leo ,I will do my best to let all interested parties know how I get on . I am very interested in the process as its something I have never done before as I am very new to having a digital scope . The nearest I got was a 7D20 for a very long time and then a 7854 but they are nothing like the TDS744 , it has no pots to adjust !!
Brian

On Friday, 31 May 2019, 20:55:10 BST, satbeginner <@satbeginner> wrote:

Hi, I have a TDS540B that I repaired, and somewhere down the line I would like to calibrate that too.

So I'm also interested in the manual calibration process :-)

I have a collection of marker and frequency generators, also some GPS controlled ones.

Looking forward to your progress,

Un saludo,

Leo

Re: TDS744 not 'A' has a problem , help needed

Stephen Hanselman
 

Leo,

Look at the earlier messages, but... what you need is a computer w/HPIB that the Tek software sees. And that is more of the problem than anything else. Next ideally is a SG503 and SG504, a good DC standard and DC meter.

The 540B needs the DMM to do the 50ohm calibration. Everything else is read the pc screen and do what it says. I’ve never counted but each channel is calibrated on each range (4 steps each rage step) and then ch1 to ch2, ch1 to ch3, etc (12 steps each) then the time base is fairly straight forward about 25 steps for each of 2 programs. In other words long and boring. I’ve had 540Bs that took 3 min for each of the vert amp cal steps, then others that went in 30 Sec or so.

You might also want to look for “clearerr.exe” this cleans the log files off of the scope

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.

On May 31, 2019, at 13:02, Brian via Groups.Io <brianas1948=yahoo.co.uk@groups.io> wrote:

Hi Leo ,I will do my best to let all interested parties know how I get on . I am very interested in the process as its something I have never done before as I am very new to having a digital scope . The nearest I got was a 7D20 for a very long time and then a 7854 but they are nothing like the TDS744 , it has no pots to adjust !!
Brian

On Friday, 31 May 2019, 20:55:10 BST, satbeginner <@satbeginner> wrote:

Hi, I have a TDS540B that I repaired, and somewhere down the line I would like to calibrate that too.

So I'm also interested in the manual calibration process :-)

I have a collection of marker and frequency generators, also some GPS controlled ones.

Looking forward to your progress,

Un saludo,

Leo





DSA602A Random Power Off

will.kibler@...
 

Greetings! I recently purchased an eBay DSA602A. No errors but after it warms up or during an EA process it will make a pop sound and shut down randomly. Sometimes it comes back on it's own but will not stay on more than 5 minutes. The pop sound is a "static discharge to chassis" type noise which could just be the unit suddenly powering down the CRT after a fault. So may be unrelated to the issue.

My question is: where do I start?

Any help would be appreciated.

Thank you.

Re: Strange 7854 problem with bracket holding digital boards

unclebanjoman
 

Usually this is symptom of a poor contact somewhere. Have you tried to unplug then plug all boards firmly in their connectors, one by one? Eventually, clean their pcb's edge connectors before reinserting them.

Max

Re: 2215 problem

tom jobe <tomjobe@...>
 

Thanks Everyone,
I've been enjoying this recent 2215 discussion! I have never owned one but have wondered what they were all about. The early version of the 2215 I had seen used a scary looking power supply, and until the other day I did not realize it had later been improved with basically what was done for the 2215A, 2235, etc. scopes which probably came out slightly after the scopes such as the 2213 and 2215.
I have some of 22xx family of scopes that includes the 2215A and 2235, and have powered the primary side of the power supply with a floating external 43 volts DC using the two test points (TP940 and TP950) several times. I would imagine that you could put in the 43 volts DC at the corresponding test points on the 2215 which appear to be TP940 and TP934. Your 43 volt power supply has to be floating and not tied to chassis or earth  ground in any way. Today I was working on a 2235 and I checked the DC voltage difference between chassis ground and TP950 (the floating 43 volt ground of the 2235) and there was a 68 volt difference! One time I got a bit sloppy and momentarily shorted the chassis ground to the 43 volt floating ground when the scope was running in its normal configuration, and there were some very burnt components as a result.
My guess would be that your chassis ground and 43 volt floating ground will differ by many volts as well.
In reading about the 2215 power supply, I saw some mention of it being a one amp supply so I wonder how well your 0.5 amp supply will work.
On the later scopes such as the 2215A and the 2235, I think it takes something like 1.0 to 1.6 amps of 43 volts to run the power supply using an external 43 volt supply, but maybe the 2215 takes less amps to run.
Let's see what others have to say about all of this before you do anything with your 2215 and the external 43 volt supply.
tom jobe...

On 5/30/2019 9:56 AM, Bob Albert via Groups.Io wrote:
Thanks for your comments on repairing the unit.  I need to keep a clear head on this.  I have some spare IRF820s now but before I install I will see about supplying 43 Volts.  I have a little 0-50V 500 mA supply I can use for that once I see where to connect it.  Any help on that?
I have far too many projects, several units laying around apart and no room to work.  But I do have lots of working gear so there is still a rather complete setup available.  Even the microwave oven in the kitchen needs some attention.  I just replaced the stove top and the garbage disposer and did some yard cleanup and snaked out a couple of drains.
Life is a lot of fun and if I didn't have these repair jobs I would wonder why I have all this gear.  At this point I would like to get at least one unit working again to free up workspace.
Bob
On Thursday, May 30, 2019, 9:19:01 AM PDT, <tekscopegroup@...> wrote:
About 10+ years ago I fixed my first scope, it was a 2213A given to me "on loan" and of course the main problem as in many of these 22xx was it would not power up, just a flash of the power Led about once a second. At the time one could only find online for gratis download the 2213 service manual that does not fully match the A version, specially in regards to the PS section so troubleshooting was tougher from the start. I remember trying to make the preregulator section work, that is what generates the 43V for the actual power supply switcher, and it was frustrating, to say the least, specially if you make simple mistakes you very easily end up burning or blowing up something in that section that was good (Mosfet, resistors, the TIP3x or TIP4x (I think it was) TO-220 transistors, Regulator IC, etc). And as I can remember the preregulator will refuse to start even if perfectly ok without the load provided by the second stage of the power supply. So I used an external power supply to feed the +43V and the scope would still not power up, just the same flicker of the power led. So then I checked all the power supply outputs, rectifier diodes, capacitors, etc. Nothing. Finally since the problem seemed to start pointing towards some other part on the board for which I did not have a replacement, someone in this group (while still at Yahoo) send me a whole 2213A main board  for the cost of shipping, it was partially gutted but it still had most key parts I needed. Turns out in the end the problem was the main switching transformer T948 that apparently had developed a short in one of the secondaries and was causing the whole power supply to shut down at startup.

So before you mess around any further with the preregulator section chasing windmills and possibly causing more damage, I would suggest that your very first step should be to test the second switcher section of the power supply by feeding it around +43V and see if the scope powers up. If it does then you will know for sure the problem is not in the preregulator but somewhere else, and leave it alone until you can get the scope to power up with the external DC supply. Another possibility is that one of the power supply outputs are looking into a short or higher than expected current draw, it could be just a dried out capacitor, leaky or shorted (fast) rectifier diode, or could be it something downstream in the circuits being powered. I recall there are some jumpers that can be removed to insulate  one or more of the power supply outputs at a time from their respective loads, but you need to at least keep a proper load on one of the outputs (I think it is the +8.6V) with a adequate size/value resistor, otherwise things will not be stable and the test will lead you nowhere else but into yet another wrong rabbit hole.

Again, it is amazing how sensitive and temperamental the preregulator is to very simple mistakes specially with all the high power parts, even when you think you just removed or replaced a part only to quickly check if there might be any changes and you are sure it should be perfectly safe there is no way something will go wrong, bum! it will usually blow up that part and/or something else and/or let out the magic smoke. Welcome to switching power supply troubleshooting.

BTW, first thing should be to get an accurate service manual for your version of the scope. That makes a huge difference. And good luck, the 2215 is a nice basic scope well worth fixing.



Re: 2215 problem

Bob Albert
 

So if my 500 mA supply won't cut it, could I use a 40 Volt supply?  I have that and, if worse came to worst, I could piggy back it with another supply, say 13V, and set the other one at 30V.  But if 40V is enough then I want to do it that way.
Bob

On Friday, May 31, 2019, 6:15:54 PM PDT, tom jobe <tomjobe@...> wrote:

Thanks Everyone,
I've been enjoying this recent 2215 discussion! I have never owned one
but have wondered what they were all about. The early version of the
2215 I had seen used a scary looking power supply, and until the other
day I did not realize it had later been improved with basically what was
done for the 2215A, 2235, etc. scopes which probably came out slightly
after the scopes such as the 2213 and 2215.
I have some of 22xx family of scopes that includes the 2215A and 2235,
and have powered the primary side of the power supply with a floating
external 43 volts DC using the two test points (TP940 and TP950) several
times. I would imagine that you could put in the 43 volts DC at the
corresponding test points on the 2215 which appear to be TP940 and
TP934. Your 43 volt power supply has to be floating and not tied to
chassis or earth  ground in any way. Today I was working on a 2235 and I
checked the DC voltage difference between chassis ground and TP950 (the
floating 43 volt ground of the 2235) and there was a 68 volt difference!
One time I got a bit sloppy and momentarily shorted the chassis ground
to the 43 volt floating ground when the scope was running in its normal
configuration, and there were some very burnt components as a result.
My guess would be that your chassis ground and 43 volt floating ground
will differ by many volts as well.
In reading about the 2215 power supply, I saw some mention of it being a
one amp supply so I wonder how well your 0.5 amp supply will work.
On the later scopes such as the 2215A and the 2235, I think it takes
something like 1.0 to 1.6 amps of 43 volts to run the power supply using
an external 43 volt supply, but maybe the 2215 takes less amps to run.
Let's see what others have to say about all of this before you do
anything with your 2215 and the external 43 volt supply.
tom jobe...

On 5/30/2019 9:56 AM, Bob Albert via Groups.Io wrote:
  Thanks for your comments on repairing the unit.  I need to keep a clear head on this.  I have some spare IRF820s now but before I install I will see about supplying 43 Volts.  I have a little 0-50V 500 mA supply I can use for that once I see where to connect it.  Any help on that?
I have far too many projects, several units laying around apart and no room to work.  But I do have lots of working gear so there is still a rather complete setup available.  Even the microwave oven in the kitchen needs some attention.  I just replaced the stove top and the garbage disposer and did some yard cleanup and snaked out a couple of drains.
Life is a lot of fun and if I didn't have these repair jobs I would wonder why I have all this gear.  At this point I would like to get at least one unit working again to free up workspace.
Bob
      On Thursday, May 30, 2019, 9:19:01 AM PDT, <tekscopegroup@...> wrote:
 
  About 10+ years ago I fixed my first scope, it was a 2213A given to me "on loan" and of course the main problem as in many of these 22xx was it would not power up, just a flash of the power Led about once a second. At the time one could only find online for gratis download the 2213 service manual that does not fully match the A version, specially in regards to the PS section so troubleshooting was tougher from the start. I remember trying to make the preregulator section work, that is what generates the 43V for the actual power supply switcher, and it was frustrating, to say the least, specially if you make simple mistakes you very easily end up burning or blowing up something in that section that was good (Mosfet, resistors, the TIP3x or TIP4x (I think it was) TO-220 transistors, Regulator IC, etc). And as I can remember the preregulator will refuse to start even if perfectly ok without the load provided by the second stage of the power supply. So I used an external power supply to feed the +43V and the scope would still not power up, just the same flicker of the power led. So then I checked all the power supply outputs, rectifier diodes, capacitors, etc. Nothing. Finally since the problem seemed to start pointing towards some other part on the board for which I did not have a replacement, someone in this group (while still at Yahoo) send me a whole 2213A main board  for the cost of shipping, it was partially gutted but it still had most key parts I needed. Turns out in the end the problem was the main switching transformer T948 that apparently had developed a short in one of the secondaries and was causing the whole power supply to shut down at startup.

So before you mess around any further with the preregulator section chasing windmills and possibly causing more damage, I would suggest that your very first step should be to test the second switcher section of the power supply by feeding it around +43V and see if the scope powers up. If it does then you will know for sure the problem is not in the preregulator but somewhere else, and leave it alone until you can get the scope to power up with the external DC supply. Another possibility is that one of the power supply outputs are looking into a short or higher than expected current draw, it could be just a dried out capacitor, leaky or shorted (fast) rectifier diode, or could be it something downstream in the circuits being powered. I recall there are some jumpers that can be removed to insulate  one or more of the power supply outputs at a time from their respective loads, but you need to at least keep a proper load on one of the outputs (I think it is the +8.6V) with a adequate size/value resistor, otherwise things will not be stable and the test will lead you nowhere else but into yet another wrong rabbit hole.

Again, it is amazing how sensitive and temperamental the preregulator is to very simple mistakes specially with all the high power parts, even when you think you just removed or replaced a part only to quickly check if there might be any changes and you are sure it should be perfectly safe there is no way something will go wrong, bum! it will usually blow up that part and/or something else and/or let out the magic smoke. Welcome to switching power supply troubleshooting.

BTW, first thing should be to get an accurate service manual for your version of the scope. That makes a huge difference. And good luck, the 2215 is a nice basic scope well worth fixing.




Re: 2215 problem

tom jobe <tomjobe@...>
 

I have no idea what you can get away with for the external 43 volt supply, because it has been easy for me to make the voltage be whatever was asked for.
Perhaps someone else will know your minimum voltage answer?
tom jobe...

On 5/31/2019 6:32 PM, Bob Albert via Groups.Io wrote:
So if my 500 mA supply won't cut it, could I use a 40 Volt supply?  I have that and, if worse came to worst, I could piggy back it with another supply, say 13V, and set the other one at 30V.  But if 40V is enough then I want to do it that way.
Bob
On Friday, May 31, 2019, 6:15:54 PM PDT, tom jobe <tomjobe@...> wrote:
Thanks Everyone,
I've been enjoying this recent 2215 discussion! I have never owned one
but have wondered what they were all about. The early version of the
2215 I had seen used a scary looking power supply, and until the other
day I did not realize it had later been improved with basically what was
done for the 2215A, 2235, etc. scopes which probably came out slightly
after the scopes such as the 2213 and 2215.
I have some of 22xx family of scopes that includes the 2215A and 2235,
and have powered the primary side of the power supply with a floating
external 43 volts DC using the two test points (TP940 and TP950) several
times. I would imagine that you could put in the 43 volts DC at the
corresponding test points on the 2215 which appear to be TP940 and
TP934. Your 43 volt power supply has to be floating and not tied to
chassis or earth  ground in any way. Today I was working on a 2235 and I
checked the DC voltage difference between chassis ground and TP950 (the
floating 43 volt ground of the 2235) and there was a 68 volt difference!
One time I got a bit sloppy and momentarily shorted the chassis ground
to the 43 volt floating ground when the scope was running in its normal
configuration, and there were some very burnt components as a result.
My guess would be that your chassis ground and 43 volt floating ground
will differ by many volts as well.
In reading about the 2215 power supply, I saw some mention of it being a
one amp supply so I wonder how well your 0.5 amp supply will work.
On the later scopes such as the 2215A and the 2235, I think it takes
something like 1.0 to 1.6 amps of 43 volts to run the power supply using
an external 43 volt supply, but maybe the 2215 takes less amps to run.
Let's see what others have to say about all of this before you do
anything with your 2215 and the external 43 volt supply.
tom jobe...

On 5/30/2019 9:56 AM, Bob Albert via Groups.Io wrote:
  Thanks for your comments on repairing the unit.  I need to keep a clear head on this.  I have some spare IRF820s now but before I install I will see about supplying 43 Volts.  I have a little 0-50V 500 mA supply I can use for that once I see where to connect it.  Any help on that?
I have far too many projects, several units laying around apart and no room to work.  But I do have lots of working gear so there is still a rather complete setup available.  Even the microwave oven in the kitchen needs some attention.  I just replaced the stove top and the garbage disposer and did some yard cleanup and snaked out a couple of drains.
Life is a lot of fun and if I didn't have these repair jobs I would wonder why I have all this gear.  At this point I would like to get at least one unit working again to free up workspace.
Bob
      On Thursday, May 30, 2019, 9:19:01 AM PDT, <tekscopegroup@...> wrote:

  About 10+ years ago I fixed my first scope, it was a 2213A given to me "on loan" and of course the main problem as in many of these 22xx was it would not power up, just a flash of the power Led about once a second. At the time one could only find online for gratis download the 2213 service manual that does not fully match the A version, specially in regards to the PS section so troubleshooting was tougher from the start. I remember trying to make the preregulator section work, that is what generates the 43V for the actual power supply switcher, and it was frustrating, to say the least, specially if you make simple mistakes you very easily end up burning or blowing up something in that section that was good (Mosfet, resistors, the TIP3x or TIP4x (I think it was) TO-220 transistors, Regulator IC, etc). And as I can remember the preregulator will refuse to start even if perfectly ok without the load provided by the second stage of the power supply. So I used an external power supply to feed the +43V and the scope would still not power up, just the same flicker of the power led. So then I checked all the power supply outputs, rectifier diodes, capacitors, etc. Nothing. Finally since the problem seemed to start pointing towards some other part on the board for which I did not have a replacement, someone in this group (while still at Yahoo) send me a whole 2213A main board  for the cost of shipping, it was partially gutted but it still had most key parts I needed. Turns out in the end the problem was the main switching transformer T948 that apparently had developed a short in one of the secondaries and was causing the whole power supply to shut down at startup.

So before you mess around any further with the preregulator section chasing windmills and possibly causing more damage, I would suggest that your very first step should be to test the second switcher section of the power supply by feeding it around +43V and see if the scope powers up. If it does then you will know for sure the problem is not in the preregulator but somewhere else, and leave it alone until you can get the scope to power up with the external DC supply. Another possibility is that one of the power supply outputs are looking into a short or higher than expected current draw, it could be just a dried out capacitor, leaky or shorted (fast) rectifier diode, or could be it something downstream in the circuits being powered. I recall there are some jumpers that can be removed to insulate  one or more of the power supply outputs at a time from their respective loads, but you need to at least keep a proper load on one of the outputs (I think it is the +8.6V) with a adequate size/value resistor, otherwise things will not be stable and the test will lead you nowhere else but into yet another wrong rabbit hole.

Again, it is amazing how sensitive and temperamental the preregulator is to very simple mistakes specially with all the high power parts, even when you think you just removed or replaced a part only to quickly check if there might be any changes and you are sure it should be perfectly safe there is no way something will go wrong, bum! it will usually blow up that part and/or something else and/or let out the magic smoke. Welcome to switching power supply troubleshooting.

BTW, first thing should be to get an accurate service manual for your version of the scope. That makes a huge difference. And good luck, the 2215 is a nice basic scope well worth fixing.







Re: 2465B battery

Mark Schutzer
 

The battery is part of a Dallas chip part number DS1225Y and this is a non volatile SRAM chip.

It’s a 28 pin dip part that is soldered into the board. To replace you need to unsolder the part, use a suitable programmer to read out the contents and copy the data into the new part. It’s also a good idea to add a socket to the board for future replacements.

Does anyone have a spare tektronix 013-0208-02 hook adapter?

tekscopegroup@...
 

Noticed that one of my P6137 probes came with the wrong witch's hat and was causing erratic behavior. Upon closer examination I noticed the internal mating point of the hook adapter to the probe tip is actually too wide and designed for a wider 3.5mm probe tip (it works just fine if I use it with the 013-0202-02 2.5-to-3.5mm adapter). I compared it to the working adapter of the other probe and a smaller gap at the mating point is immediately apparent.

So looking at the Subminiature (2.5mm) Probe System Accessories diagram at the link bellow, it seems I am in need of the correct hook adapter which is PN 013-0208-02, but there are currently none on ebay.

http://w140.com/tekwiki/wiki/File:Subminiature_probe_system_accessories_1.jpg

Anyone have one 013-0208-0x kicking around that they want to sell? Even a used one in good shape would be fine.
Paypal & ship to zip 33152 FL.

Thanks for looking.
Alex

Re: 2215 problem

tekscopegroup@...
 

I am pretty sure that 500mA will not be enough to start the scope, so you might see it folding back, specially during startup, and then this could be misinterpreted as there being a problem in the second stage of the scope power supply. I can't remember exactly which external power supply I used back then to run this test but it was close, probably 42V if not dead on 43. I think it was a 48V supply that I managed to dial down... or maybe it was the Heathkit IP-27 which can deliver up to 50V and 1.5A.

In any case if you got only 40V give it a go, but if the scope doesn't power up in max 1-2 seconds (keep an eye on the green front panel power LED) watch for any abnormalities in the scope (heat, smoke, etc) and be prepared to shut down everything very quickly, ideally with just the flick of a switched AC outlet.

But definitively do this test first. It would have saved me a lot of grief had I done the same in my scope.

Let us know how it goes.
Alex

Re: Clock error on TDS3034

Harvey White
 

Ah, now that's the difference.  These were specifically made to replace CCFL tubes.  I was thinking of something else, a more common LED strip.  I'll look them up.  I have more than enough of them, and assembling them isn't much of a chore, but that ought to work for lots of people as long as the voltages are OK.

Harvey

On 5/31/2019 1:48 PM, Bob Koller via Groups.Io wrote:
The strips I have are 5mm pitch LED, and 2mm wide. Obtained, as I recall on eBay as CCFL cut-to-length retrofit strips.



Re: 2215 problem

tekscopegroup@...
 

On Fri, May 31, 2019 at 06:15 PM, tom jobe wrote:
Thanks Everyone,
I've been enjoying this recent 2215 discussion! I have never owned one
but have wondered what they were all about.
Tom, as far as I know, the 2215/A is basically a 2213/A only with dual time base. No other differences, I think.

Alex

Re: 2215 problem

Bob Albert
 

Alex, as soon as I get the nerve I will see what I can do.  But I just might stack two supplies with a diode in between to get the 43V. 
What I do know is that the guys at Tektronix who designed this had no concept of what service people have to do.  Oh so clever and so possible to package in a small box.  Yeah I would love to see those engineers in a small box.
Just getting to the power switch is an exercise in lost screws and dangling boards.  The only thing that keeps me going is how nice the unit is when it works.  Maybe I will cobble up a 43 Volt power supply to run it, rather than fix its own problems.  I could put such a unit nicely out of sight on the desk.  After all, power supplies were one of my specialties in my engineering days.
Bob

On Friday, May 31, 2019, 10:14:31 PM PDT, <tekscopegroup@...> wrote:

On Fri, May 31, 2019 at 06:15 PM, tom jobe wrote:
Thanks Everyone,
I've been enjoying this recent 2215 discussion! I have never owned one
but have wondered what they were all about.
Tom, as far as I know, the 2215/A is basically a 2213/A only with dual time base. No other differences, I think.

Alex

Re: Does anyone have a spare tektronix 013-0208-02 hook adapter?

Stephen Hanselman
 

I’ll look in my spares on Monday. We have 400 or so probes. And a BIG box of spare parts.

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
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On May 31, 2019, at 21:26, tekscopegroup@... wrote:

Noticed that one of my P6137 probes came with the wrong witch's hat and was causing erratic behavior. Upon closer examination I noticed the internal mating point of the hook adapter to the probe tip is actually too wide and designed for a wider 3.5mm probe tip (it works just fine if I use it with the 013-0202-02 2.5-to-3.5mm adapter). I compared it to the working adapter of the other probe and a smaller gap at the mating point is immediately apparent.

So looking at the Subminiature (2.5mm) Probe System Accessories diagram at the link bellow, it seems I am in need of the correct hook adapter which is PN 013-0208-02, but there are currently none on ebay.

http://w140.com/tekwiki/wiki/File:Subminiature_probe_system_accessories_1.jpg

Anyone have one 013-0208-0x kicking around that they want to sell? Even a used one in good shape would be fine.
Paypal & ship to zip 33152 FL.

Thanks for looking.
Alex