Date   

Re: 2440 seems to crash when switched less than 200ns/div?

 

On 27 May 2016 19:59:04 -0700, you wrote:

I did the unthinkable in my current situation, and now I have one more scope: It's a 2440 to complement the 2465.

It was sold as defective/parts only, and wasn't dirt cheap (I could have paid about 50% more and gotten a completely working one -- but it sold before I flinched. I was thinking that one was a tad underpriced). After futzing with it, fortunately I think three (well, four or maybe five) things are wrong with it:

1,2 - Battery is dead and External Calibration data lost :-(
Battery was completely flat at 0V. I desolderd the battery and used two alkaline AAA's as the Sony 32KB memory chips should be able to retain data even with this low of voltage. However the voltage is not quite high enough to trigger selftest as good. Will need to look for a 3.6V battery at some point.
Luckily the external calibration is relatively easy to do. You need a
stable voltage source any fast edge. The edge could be the synch
output from a function generator or even a TTL output.

Three alkaline AA batteries for a nominal 4.5 volts would work.

3 - The serious problem: If I switch the time/div to less than 200 ns/div range, the scope goes haywire, possibly crashes and blinks the trigger LEDs. Slower than 200ns/div looks OK. I think it's also temperature sensitive but need to experiment with this some more. I'm thinking bad capacitors in the LVPSU but still trying to coming up with hypothesis.
The loss of the calibration data may be responsible for this. As I
recall, there is an command in the service menu which reloads the
default calibration data and affects the CCD system.

Levels and noise on the low voltage power supply outputs should be
checked of course. I have seen high noise here affect the digitizer.

4,5 - the plastic fan mount cracked, and just like my 2465 it's also missing that oh-so--annoying-when-missing clear piece over the power button...

So far other than the somewhat noisy waveforms and that crash problem, it looks like it's working, seems I once got everything on the selftest to say "PASS" except for the battery! If I can figure out why it goes bonkers at fast "sweep" speeds, this looks like a winner. So far: I like this 2440. I don't recall ever actually using a DSO before and this exceeds my expectations, even if newer ones can sample faster and have deeper memory.

-Ben
I find the 2440 to be very usable with a faster interface than most
modern low end DSOs.


Re: Module A64, 492BP deflection amp

Artek Manuals <manuals@...>
 

Gerald

You might also try scouting the later 275x series analyzer manuals the A64 and A64A1 boards were common between these models and the 492B

The further add to the confusion the 670-8083-xx number is for A64A1 not A64 ????

The 671-0803-00 board is noted in one change document I have as being for Option 43 but no further info on the board itself or the even what Option 43 is ..not much help but perhaps a clue??

73
Dave
NR1DX
manuals@artekmanuals.com



I have a 1990 late model Tek 492BP SA with a deflection amp fault. There
are several versions of PCB releases and the one I have is a
671-0803-00, no typing error.


This PCB is quite different to all PCB and schematics I have seen and
all refer to part No. 670-8083-00.


Has anyone come across a late model deflection amp with a sticker
stating 670-0803-00, I would appreciate any feedback and schematic
information.


Thank you in advance.


Regards


Gerald
VK3GJM
--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com


Re: 2440 seems to crash when switched less than 200ns/div?

bc
 

I noticed some CCD tests intermittently fail, and notice CRT flickering. Also in regular acquire mode in in the low time/division (100ns or shorter). I also noticed that the CRT flickers. The only thing that seem a little weird - I see some really sharp upward ramps and fast collapses in the +5 (analog I guess, not the digital one) power rail, these are 0.4V sawtooths that are really visible amongst the switching noise which are very small. These "big" glitches are happening at the same time as the jitters on the CRT, and I see these only in the 100ns or shorter time/division modes. I'm still trying to locate where I can probe the CRT power input, suspecting the same behavior is happening.

Trying to get these events to trigger on my 2465 and failing; using AC coupling as the 5V offset is drowning out most of the noise. They look like it sharply drops 200mV in 1ms, rises 400mV in about 0.7ms, and then drops back down to nominal instantly - so I see some checkmarks in the waveform, and cant say these are cap issues... ugh.


Re: New file uploaded to TekScopes

Albert Otten
 

These files of Alberto actually were pictures and are in the Photos section now.
Albert


---In TekScopes@yahoogroups.com, <grbosworth@...> wrote :

Invalid path. Could not see the post.


Module A64, 492BP deflection amp

Gerald
 

Hi All,


I have a 1990 late model Tek 492BP SA with a deflection amp fault. There are several versions of PCB releases and the one I have is a 671-0803-00, no typing error.


This PCB is quite different to all PCB and schematics I have seen and all refer to part No. 670-8083-00.


Has anyone come across a late model deflection amp with a sticker stating 670-0803-00, I would appreciate any feedback and schematic information.


Thank you in advance.


Regards


Gerald
VK3GJM


Re: Need help finding Lithium backup battery for a Tek 2430A

 

A Google search of "LTC-16P-CO-F-S2" turned up that this item is a
discontinued Eagle-Picher 3.5V 1600mAH non-rechargeable "Electronic
Battery". Searching Mouser for "Electronic Battery" turned up several
possible replacements. The closest is an Eagle-Picher LTC16M-S4
<http://www.mouser.com/ProductDetail/Eagle-Picher/LTC16M-S4/?qs=sGAEpiMZZMtLoaml0iHoQygV9CKexg4%252b6r0Z3tWjBYM%3d>;
with
the same specs as the LTC-16P battery. The LTC16M is $35.47, but is out of
stock until 7/28/16. There is a 750MAH version for $15.82 that looks like
it might work but with half the life. What I found intriguing was the
PT-2150
<http://www.mouser.com/ProductDetail/Eagle-Picher/PT-2150/?qs=sGAEpiMZZMtLoaml0iHoQygV9CKexg4%252bhlhCbuhmmYA%3d>;
3.5V 2400MAH AA style battery for $8.68. This would require a bit of
engineering to fit, probably a battery holder & remote mounting. I'm
thinking the miniscule current flow through the added wiring won't upset
any other circuitry on the board....

I might take a look at trying this when I tear my 2430A apart to the point
that I can locate and identify the backup battery. So far I haven't
attempted to pull the time base/display board yet, but the U431 16K static
RAM fails on the diagnostic test so I will be swapping that out next week
when I get a new chip. That will afford me the opportunity to take a look
at my processor board & see what I think I can do.


Re: Introduction, 2440 cal,

Jeff Woolsey
 

On 4/23/16 8:28 AM, David davidwhess@gmail.com [TekScopes] wrote:


I did the same thing the first time I did the external calibration on
my 2440 after being unable to read the contents of the nonvolatile
SRAM with my programmer. I used the sync output from my 2 MHz analog
function generator for the channel delay alignment and a PS503A,
switched RF attenuator, and 4 digit voltmeter for the DC levels. Later
I did the calibration again with a PG506 and it went much faster.
Mine is not being so cooperative with EXT CAL, ATTEN. It FAILs every
time. I'm using a variable power supply and a voltage divider (with a
resistor substitution box) with a Fluke 8860A (which reports my
DMMCheckPlus at 5.0003V, which ought to be close enough for a scope).
Is there some problem with how long the scope can wait between the
steps, since it takes a while to set the voltages each time (and why
can't I do the same voltage on each channel sequentially, so I only have
to set them three times, not six, and each channel will get, in turn,
the same value for each voltage?)? Sigh.

I haven't tried the delay part yet. I have a demo board with a sub-ns
edge I can use, though.

As for a PG506, I've already spent too much money getting this scope
usable. It's a hobby, anyway.

--
Jeff Woolsey {{woolsey,jlw}@jlw,first.last@{gmail,jlw}}.com
Nature abhors straight antennas, clean lenses, and empty storage.
"Delete! Delete! OK!" -Dr. Bronner on disk space management
Card-sorting, Joel. -Crow on solitaire


Re: Need help finding Lithium backup battery for a Tek 2430A

bc
 

I was working on my 2440 and pulled out a dead "Lithium Keeper" 3.5V/1.6AH model LTC-16P-CO-F-S2.  Not sure if they're still being produced, but I found that 3.0V from either a MnO2 Lithium primary cell or two Alkaline cells is not enough to make the self test happy - though it will keep the RAM data intact while trying to find a stopgap solution to keep RAM contents.

I thought I saw a couple of the "newer" 2440s and I would imagine the 2430A would have the Dallas Semiconductor embedded battery RAMs like the 24x5A/B's... but I guess if the service manual says no, it must be so.
The battery in my 2440 is(WAS) on the processor board which can be seen after lifting up the top board hinge.

-Ben

On Wednesday, May 25, 2016 10:07 PM, "houdatto@gmail.com [TekScopes]" <TekScopes@yahoogroups.com> wrote:


  Can anyone give me some help identifying the NVRAM Lithium backup battery for a Tek 2430A? The 2430 service manual identifies the battery for that model as a 3.5V, 750mah LTC-7P, which is easy to find commercially. However, the 2430A service manual identifies the battery for that model as a 3.5V, 1.6AH battery but gives only the Tektronix part number 146-0062-00. Obviously the batteries are different between the two models and I have had no luck finding a commercial part number for the 2430A. Can someone point me in the right direction???


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Re: 2440 seems to crash when switched less than 200ns/div?

Jeff Woolsey
 

On 5/27/16 7:59 PM, laser92awd@yahoo.com [TekScopes] wrote:

3 - The serious problem: If I switch the time/div to less than 200
ns/div range, the scope goes haywire, possibly crashes and blinks the
trigger LEDs. Slower than 200ns/div looks OK. I think it's also
temperature sensitive but need to experiment with this some more. I'm
thinking bad capacitors in the LVPSU but still trying to coming up
with hypothesis.
Mine did that, but at a different speed, like 100us IIRC. If you dig
into the diagnostics report for the CCDs, you'll eventually find four
different speeds listed, and I bet you'll find the faster ones fail.

AUTO SETUP would also go out to lunch.

What I find interesting is the number of problems that go away when the
power supply voltages are correct, and even more when the capacitors are
fresh. A bunch more after a SELF CAL. So much so that I do not know
what caused the problems in the first place.

Essentially, no components that the diagnostics complained about were
actually faulty (except perhaps NVRAM).

4,5 - the plastic fan mount cracked,
Mine fell out when I had it open for something. I just put it back; the
case holds it there. Make sure the holes in the case line up with it.

So far other than the somewhat noisy waveforms
Recapping worked wonders for that. I had some significant ripple
(almost a division).

and that crash problem, it looks like it's working, seems I once got
everything on the selftest to say "PASS" except for the battery! If I
can figure out why it goes bonkers at fast "sweep" speeds, this looks
like a winner. So far: I like this 2440. I don't recall ever actually
using a DSO before and this exceeds my expectations, even if newer
ones can sample faster and have deeper memory.

-Ben
I liked it so much that I have two of them. Actually, the original plan
was to get a second "broken" one and make one good one from the pair.
However, the second one was easy to fix, and the first one became a
matter of honor.

I thought I'd miss having an analog mode in a digital scope, but I don't
so much. Besides, I have other scopes for that.


BTW. I hate those plastic cam screws.
You and me both. I'd be surprised if more than half of mine are intact.


And go ahead, try a control: make my day.
I do that, but it doesn't seem all that grateful.

--
Jeff Woolsey {{woolsey,jlw}@jlw,first.last@{gmail,jlw}}.com
Nature abhors straight antennas, clean lenses, and empty storage.
"Delete! Delete! OK!" -Dr. Bronner on disk space management
Card-sorting, Joel. -Crow on solitaire


2440 seems to crash when switched less than 200ns/div?

bc
 

I did the unthinkable in my current situation, and now I have one more scope: It's a 2440 to complement the 2465.

It was sold as defective/parts only, and wasn't dirt cheap (I could have paid about 50% more and gotten a completely working one -- but it sold before I flinched. I was thinking that one was a tad underpriced). After futzing with it, fortunately I think three (well, four or maybe five) things are wrong with it:

1,2 - Battery is dead and External Calibration data lost :-(
Battery was completely flat at 0V. I desolderd the battery and used two alkaline AAA's as the Sony 32KB memory chips should be able to retain data even with this low of voltage. However the voltage is not quite high enough to trigger selftest as good. Will need to look for a 3.6V battery at some point.
3 - The serious problem: If I switch the time/div to less than 200 ns/div range, the scope goes haywire, possibly crashes and blinks the trigger LEDs. Slower than 200ns/div looks OK. I think it's also temperature sensitive but need to experiment with this some more. I'm thinking bad capacitors in the LVPSU but still trying to coming up with hypothesis.
4,5 - the plastic fan mount cracked, and just like my 2465 it's also missing that oh-so--annoying-when-missing clear piece over the power button...

So far other than the somewhat noisy waveforms and that crash problem, it looks like it's working, seems I once got everything on the selftest to say "PASS" except for the battery! If I can figure out why it goes bonkers at fast "sweep" speeds, this looks like a winner. So far: I like this 2440. I don't recall ever actually using a DSO before and this exceeds my expectations, even if newer ones can sample faster and have deeper memory.

-Ben


BTW. I hate those plastic cam screws.

And go ahead, try a control: make my day.


Re: New file uploaded to TekScopes

Gary Robert Bosworth
 

Invalid path. Could not see the post.

On Fri, May 27, 2016 at 3:21 AM, <TekScopes@yahoogroups.com> wrote:




Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the TekScopes
group.

File : /"new" Tek 7904A/IMG_4422_800x600.jpg
Uploaded by : iz2ewv <iz2ewv@yahoo.com>
Description : 7904A, PSU left side

You can access this file at the URL:

https://groups.yahoo.com/neo/groups/TekScopes/files/%22new%22%20Tek%207904A/IMG_4422_800x600.jpg

To learn more about file sharing for your group, please visit:

https://help.yahoo.com/kb/index?page=content&;y=PROD_GRPS&locale=en_US&id=SLN15398

Regards,

iz2ewv <iz2ewv@yahoo.com>



--
Gary Robert Bosworth
grbosworth@gmail.com
Tel: 310-317-2247


[Non-text portions of this message have been removed]


Re: 576 collector supply primary filter

Rick Doersch
 

That is a second order low pass filter network. Not sure why they included it but I'm sure there was some noise they were eliminating. The 577 has it also. If you bump up the C you will lower the filter corner probably not a good thing.


Re: Schematics for the TCP202 probe

 

If anyone on here might have a copy it might be Hakan
I have been looking for that one too without success.
The Reference (070-9543-03) and the Instruction Manual (070-9542-03) can both be downloaded from Tek's
web site but neither includes schematics.

/Håkan


Re: 576 collector supply primary filter

Ed Breya
 

Sorry for the double-post. The first time it said it could not send the message, so I tried again. Then of course (!@##$@#$&^ yahoo neo) both showed up.

Ed


576 collector supply primary filter

Ed Breya
 

I noticed in my newest 576 there's a LRC network on the primary of the collector supply transformer. The C was a 3.75 uF 236 VAC PCB oil-filled type. I try to eliminate PCB-type caps in my equipment where reasonably possible, and figured I'd replace it. I put in a 4 uF 250 VAC plastic type, and it works just fine.

I found that my other 576 of much later later SN (>300000) info showed that it uses a plastic cap with the same ratings as the older PCB one. Also, the 577 manual shows the use of a plastic cap in the equivalent position (but different value 3.3 uF). I looked back at the 575, and no filter network is shown, so it looks like the newer models incorporated it for some reason. Then the even later models used plastic caps.


I'm just wondering if anyone knows any details of why the network was added, and where the values came from. None of the circuit descriptions in the manuals even mention these parts. I assume it's to serve as a (RC) snubber on the primary, and a low-pass filter (L) to keep HF line noise out of the collector supply. These are L300, C300, and R300 on the collector supply schematic of the 576. The main thing I'm wondering is whether there's something special about the component values. For example, is more C better, or would it upset something? The new cap I put in is actually a dual (4/2.5 uF) type, but I only used the 4 uF section. If more C is good, I would also connect the 2.5 section.


Ed


576 collector supply primary filter

Ed Breya
 

I noticed in my newest 576 there's a LRC network on the primary of the collector supply transformer. The C was a 3.75 uF 236 VAC PCB oil-filled type. I try to eliminate PCB-type caps in my equipment where reasonably possible, and figured I'd replace it. I put in a 4 uF 250 VAC plastic type, and it works just fine.

I found that my other 576 of much later later SN (>300000) info showed that it uses a plastic cap with the same ratings as the older PCB one. Also, the 577 manual shows the use of a plastic cap in the equivalent position (but different value 3.3 uF). I looked back at the 575, and no filter network is shown, so it looks like the newer models incorporated it for some reason. Then the even later models used plastic caps.


I'm just wondering if anyone knows any details of why the network was added, and where the values came from. None of the circuit descriptions in the manuals even mention these parts. I assume it's to serve as a (RC) snubber on the primary, and a low-pass filter (L) to keep HF line noise out of the collector supply. These are L300, C300, and R300 on the collector supply schematic of the 576. The main thing I'm wondering is whether there's something special about the component values. For example, is more C better, or would it upset something? The new cap I put in is actually a dual (4/2.5 uF) type, but I only used the 4 uF section. If more C is good, I would also connect the 2.5 section.


Ed


Schematics for the TCP202 probe

Artek Manuals <manuals@...>
 

On 5/27/2016 3:09 PM, bdd4@att.net [TekScopes] wrote:
I allow a Philips PM3260 scope to sit on the same bench as my Tek
scopes? Also, do you know where I can find a schematic for my blown Tek
TCP 202 Current Probe? - Thx - Bankole



If anyone on here might have a copy it might be Hakan who lurks on this list. If they do exist they may be in the document "TCP202 Technical Reference" / Tektronix part number 070-9543-0?. But I have been unable to find a copy to date.

I suspect if Hakan does not have a copy then If the schematics ever existed for the TCP202 they are either in a 3rd level basement in Beaverton, OR guarded by Ninja Accountants and Green Beret lawyers....

or

They were destroyed by disgruntled Tektronix engineers as they headed for the hills to the east at the beginning of the Danaher takeover invasion

Either way they are unlikely to ever see the light of day

As for the PM3260 on your bench ...as long as you can sleep at night I see no problem

Dave







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


Re: System Email Hiccups

bdd4@...
 

@Dave - www.ArtekManuals.com:Thx for the insights, change my password - OK ,but burn the crops, leave town?... crops almost harvest ready, house almost paid for, where would I go, cropless and homeless? Would I be welcome elsewhere since I allow a Philips PM3260 scope to sit on the same bench as my Tek scopes? Also, do you know where I can find a schematic for my blown Tek TCP 202 Current Probe? - Thx - Bankole


Re: "new" Tek 7904A on my bench

Albert Otten
 

Hi Alberto,

I see, I was thinking of A23 C5 at the Inverter board since that RC combination exploded in my 7904A and in my 7104! The problem has been discussed here. IIRC some makes are more prone to failure than some other makes.
It's too long ago that I dismantled the power supply, so I can't help you with the mechanical question.
My 7904A dates from 1986.

Albert


---In TekScopes@yahoogroups.com, <iz2ewv@...> wrote :

Hi Albert,

thank you for your reply.


I moved my photos in a new photo album, as you advised.


I am quite convinced that in my 7904A the filter is embedded with the AC socket because I saw a little shield between the flange of the socket and the panel, and the brown spot of the smoke coming out from there. More, I found a match in the exploded view: part No. -152 is described as "FILTER, RFI" (I put the drawings and the list in the album, too). My 7904A has S/N B053040 and the service manual I own is quite aligned (only one change information, dated 06/08/1991, is effective from S/N B053061).


By the way, I need to know how to open the PSU box without causing damage...



73 de IZ2EWV, Alberto


Re: Tek 2465B display shrinkage

 

While pin 7 is the precise reference point, it indirectly connects to the chassis.  So, the chassis can be used as reference for quick (approximate) measurement of DC voltages.  Millivolt accuracies (precision and noise) should be referenced to pin 7.

From: "'Tom Miller' tmiller11147@verizon.net [TekScopes]" <TekScopes@yahoogroups.com>
To: TekScopes@yahoogroups.com
Sent: Thursday, May 26, 2016 10:37 AM
Subject: Re: [TekScopes] Tek 2465B display shrinkage

  I always measure to pin 7.

----- Original Message -----
From: 'Matt Hofmann' mhofmann@sbcglobal.net [TekScopes]
To: TekScopes@yahoogroups.com
Sent: Thursday, May 26, 2016 8:35 AM
Subject: RE: [TekScopes] Tek 2465B display shrinkage

I found the table for power supply voltage tolerance in the manual and the
pins on J119, the test connector, on the main board. What it doesn't show
is where the ground reference is that I should be measuring these voltages
from. I am sure someone knows where to reference these reading from.

From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Wednesday, May 25, 2016 12:11 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Tek 2465B display shrinkage

Do a search of the archives for A5 controller smt capacitor problem.

In summary there are four SMT electrolytic caps on the A5 controller card
that leak and damage the PC board. You will need to inspect, clean, and
repair that problem first. Then have a look at the LV power supply caps.

Regards

----- Original Message -----
From: 'Matt Hofmann' mhofmann@sbcglobal.net [TekScopes]
To: TekScopes@yahoogroups.com
Sent: Wednesday, May 25, 2016 11:56 AM
Subject: [TekScopes] Tek 2465B display shrinkage

Hello all;

I am new here and I have a 2465B that has suddenly given me problems. After
about a 5 minute warm-up, the image on the screen contracts to about 2/3
normal size and it jitters so that it is unreadable. I am a long-time
Tektronix user (more than 40 years), but new to digging inside to see what
is wrong. Any ideas of where I should start? Should I look for bulging
electrolytics?

Thanks!

Matt

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