¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. TekScopes
  2. Messages
Expanded Topics Messages Polls
Date
Re: Tektronix 015-0580-00 Pocket Signal Generator

 

Thank you for the additional information. I was curious if it would be of any interesting use when I came across it by chance on ebay. I do not own any TDS series scope and upon better understanding its designed purpose I see now that it is not something I will pursue. Thanks again.
Re: 2247A PSU Troubleshooting

 

On Thu, Mar 14, 2019 at 05:18 AM, Brian Symons wrote:


*Re: Isolation Transformers*

When using an isolation transformer for troubleshooting you do not want an
earth being connected through.
The whole idea is to break any reference between earth & the mains.
The winding will make both outputs fully isolated from earth so that you can
measure them safely.
This is one time that earth is your enemy.
Brian,
Let's not confuse the OP.
He has a 'scope with a HV (mains switching power supply) part that is galvanically connected to the mains and a LV part that is under normal conditions separated from the HV part through an internal "HF" transformer (inverter output).
Safety earth is normally connected to the 'scope's chassis, not the HV part.

The OP wants to do tests in the rather complicated HV part.
By earthing the chassis and the LV part, the HV part stays isolated.

For all intents and purposes, the LV part is a second isolated part (internal transformer) and there's no reason to float the chassis.

Raymond
Re: Test input for an SD-32 sampling head

 

On Wed, Mar 13, 2019 at 05:22 PM, Reginald Beardsley wrote:
How do you test these? The 7 pS rise time is a pretty difficult spec if you
want a 10x margin.
With difficulty. I believe there's a method involving three sampling heads looking at each other's kickout pulses and some maths which can be used to evaluate their performance.

The SD-24's pulse generator has a risetime of about 16-17ps, I think, but any faster than that is tricky. The calibrator output on the 11802 (but not the 11801 or 11803/CSA803) has a similarly fast rise time, being made of the same hybrid module.

Chris
Re: Not to be missed by 7854 fans...

 

John,

Great find! Thanks for sharing. I¡¯m looking forward to seeing this!



A hoard of never-developed film from the Apollo 11 mission was unearthed, some of it in 70mm. The filmmakers also made use of a bounty of audio material whose existence was previously known but which had never before been synced to pictures.

George

On Mar 13, 2019, at 10:30 PM, John Miles <john@...> wrote:

Tek content begins around 8:58. Specifically, this is part 7 of
CuriousMarc's series on restoring an Apollo Guidance Computer, but the whole
video (and whole series) is great. You really feel like you're right there
with Marc, Ken, and Mike, trying to bring a real-life HAL back to life:







Now where'd I put that spare AE-35 unit...?



-- john, KE5FX
Not to be missed by 7854 fans...

 

Tek content begins around 8:58. Specifically, this is part 7 of
CuriousMarc's series on restoring an Apollo Guidance Computer, but the whole
video (and whole series) is great. You really feel like you're right there
with Marc, Ken, and Mike, trying to bring a real-life HAL back to life:







Now where'd I put that spare AE-35 unit...?



-- john, KE5FX
Re: Looking for Sony-Tektronix 318 Logic Analyser Operator's Guide

 

On Wed, 13 Mar 2019 13:58:49 -0700, you wrote:

On Tue, Mar 12, 2019 at 01:00 PM, Raymond Domp Frank wrote:


wading through an operator manual saves time in getting acquainted
Well, upon seeing the Operator's manual (Thanks for posting it to Tekwiki!)¡­ I can see that manual has examples of how to set up the 318, that the Army service manual doesn't give. But I guess, and this is the just of my question, I think... I just didn't recon anyone was using them, to do logic analysis, or for servicing stuff anymore (the p.c. based L.A.s are so cheap and powerful)... so I was thinking, I'm missing some use for these old LAs...(other than for technical/design/parts interest... which the service guide covers much better).
Debugging I2C data streams, FPGA outputs, video data outputs from
graphics chips.

Have a CPLD standalone board that takes apart I2C communications and
drives an HP logic analyzer. Goes from time to state and tags the
message bytes in the signal. Made a while back before cheap PC based
logic analyzers.

One blade in my logic analyzer does 64 channels, and there are times
when I've used most of them, typically 32 to monitor I2C state and 8
to 16 to monitor the results from something that got the I2C message.

Harvey



I understand what you are saying... but, most of the older L.A.s, I run across, are being used to weigh down the basement floor. If people are doing something useful with them, I'd like to do it too.
Re: Looking for Sony-Tektronix 318 Logic Analyser Operator's Guide

 

On Wed, 13 Mar 2019 13:38:43 -0700, you wrote:

On Tue, Mar 12, 2019 at 11:49 AM, Harvey White wrote:


if you regard signature analysis as fun, then you can do that.
Hi Harvey:
Thanks for the reply. There's always a few old L.A.s keeping the concrete slab down, in someone's basement... and I'm thinking about that, whenever I see one.
Logic analyzers are very useful, but somewhat limited in what they do.
They really were needed in the times of 8 and 16 bit microprocessors,
and are less useful for microcontrollers. However, since most
microcontrollers have built in debugging, you don't need to monitor
the instructions and data paths.

Monitoring the program at an assembly language level isn't as useful
as it might be when you are dealing with a compiled program.
Sometimes, however, you need to check to see what the compiler does.


The 308 has a word recognition module, and the 318/338 have word recognition modes... but, if its signature analysis... aren't captured word(s), further processed, to generate the signature? Can you do that with a 308/318/338?
Lots of logic analyzers are multiple byte wide memories with inputs
for each bit. Clocking data is either a timebase or an external
clock, so you get either a time mode/waveform display or a state mode
where only data happening at the clock is captured.

Signature mode takes a start, stop and then looks at the transitions
at a node. Those transistions are run through a shift register with
feedback, and the result is displayed in odd alphanumerics.

Not the same thing, and the data is not stored then processed in
signature mode.

308 does signature, and is a limited logic analyzer.

Don't have the other ones.

Tektronix logic analyzers and HP scopes generally drive me up a wall,
so I have tektronix scopes and HP logic analyzers.


Harvey
Re: 2247A PSU Troubleshooting

 

*Re: Isolation Transformers*

When using an isolation transformer for troubleshooting you do not want an earth being connected through.
The whole idea is to break any reference between earth & the mains.
The winding will make both outputs fully isolated from earth so that you can measure them safely.
This is one time that earth is your enemy.

Please physically check the item to make sure that there isn't an earth & test the output winding for insulation to earth.
Just in case, test both sides of the outlet (I know it should be continuous) & the higher the insulation reading (Megohms) the better.
If the transformer was being used for filtering then there may be filtering connected on the output - I would remove anything that connects to earth in any way so that it can never go faulty & give you a nasty surprise.
When you do a physical examination, if you think that an extra bit of insulation may be needed consider fitting it.
One isolation transformer I worked on had an output lead rubbing on the case so I fitted a cable tie mount & cable tie so that it was off the case.

I like to test my transformers for insulation before I use them if they haven't been used for a while.

I once talked to a linesman that had worked on High Tension systems where the system was live & he was connected to the conductor.
It was interesting to hear him say that any earth was his enemy & he considered earth like we consider a high voltage potential.


*WARNING: **Some isolation transformers are designed for mains filtering purposes & they DO have the earth connected through.*

These are often made for computers, audio systems, & sensitive electronic equipment.
These use the transformer winding to stop induced transients etc & the couple that I have seen just had the earth connected straight through apart from being connected to some filtering.*
*

*
*

*WARNING:**? Some isolation transformers have been worked on by people who do not know what they are doing & they may connect the earth through.*

I have worked on isolation transformers that suffered from both of those issues that I found on tech benches.
One that I bought was a very nicely made unit that some 'lecky had soldered an extra wire on just to earth the output socket - he did a nice neat job of making the item a death trap.

Some isolation transformers totally isolate the transformer internally & there may not be an earth except on any metal casings but many earth the transformer core for safety but the outlet socket should not have any form of earth wire going to it.
There may even be an internal sign stating to not earth the output.
The couple of isolation transformers I worked on I added a note inside if there wasn't one.


*WARNING:? Only ever connect ONE item to an isolation transformer.*

Older regulations in Australia actually had the output socket surrounded in a shield to stop anyone fitting a "piggyback plug" or double adapter but the modern use of multiple socket boards makes that a bit obsolete.

Isolation transformers for testing also use to have a warning label stating to only connect a single item to the transformer output.


The reason for only connecting a single item is in case of the rare problem of two faulty items being connected to the output.
If one item has an Active (Hot) to metal casing (earth) fault & the other has a Neutral to metal casing (earth) fault then the two items will have full mains potential across their casings.
Because there is no earth connection to trip an protective devices, touching either casing would be safe but touch both at the same time...


Regards,
Brian.

On 14-Mar.-19 00:17, Nicholas Keller wrote:
Raymond,

Per your advice (and that clearly marked on the PCB!), I have purchased an
isolation transformer. After watching a few videos online, I am still
unsure whether I should connect ground from the Tek to the transformer.
One video showed use of a 3-prong to 2-prong adapter where the ground wire
is left unattached. Is this what you describe as ¡°floating the 2247A¡±?

Thanks for your help!

Nick



On Sun, Mar 3, 2019 at 8:48 PM Nicholas Keller via Groups.Io <Nirokeforums=
[email protected]> wrote:

No, I was not using an isolation transformer (I don¡¯t have one) and yes I
was measuring between cap and chassis. I will look into getting a
transformer before testing across c2202 or doing other troubleshooting.

Thanks for the warning

Nick


On Sun, Mar 3, 2019 at 6:49 PM Raymond Domp Frank <hewpatek@...>
wrote:

On Mon, Mar 4, 2019 at 12:17 AM, Nicholas Keller wrote:

I measured 120-122VAC up to the diode ring. Does this
suggest that C2202 is bad?
I guess you realise you're measuring in an area that is directly
connected
to the mains, no isolation? Take great care! *Do* use an isolation
transformer and *float your 2247A*.

Did you measure the 77 V across C2202 or between C2202 and chassis? The
latter would be incorrect, because the chassis is floating (with
exception
of some C's) against C2202 (since that has a galvanic coupling to the
mains).

Raymond
Re: 2467B geometry

Chuck Harris
 

Hi Tom,

That occurred to me earlier, it is -970V, which seems a little
low, but there is no information on tolerance. I measured it
with both a 20M DVM, and a 200M 410C.

It would be nice to know what others measure.

It is on my list of things to try to make right before I give
up on the CRT.

-Chuck Harris

Tom Miller wrote:

How about the -1kV supply to the PDD electrode? It is regulated mostly by four series
200 volt zeners. If one of those were shorted, it would lower that supply and affect
the geometry adjustment. You can check it on J4391 on the A9 HV board.

Regards

On 3/13/2019 9:54 PM, Chuck Harris wrote:
I tried pulling the plug on trace rotation, and on
y-axis rotation, and the only effect was the trace
rotated one line width clockwise.

I guess that eliminates them, and any fringing effects
from the current in their shielded wires as they pass
down the CRT's funnel section under the mumetal shield.

What I am seeing is pretty much exactly what I would
expect to see if the box lens got moved off axis a little
bit. A hard hit on the bottom (top?) of the scope might
do that, I suppose.

-Chuck Harris

Chuck Harris wrote:
I did take the CRT out, and did not see anything
rattling about inside the shield, but it is possible
that a magnet could be stuck up in there somewhere.

The trace rotation could be eliminated by pulling
its plug. I have been meaning to try that, but
keep forgetting.

If you hold a magnet anywhere near the screen, the
trace moves drastically. Which you might expect
as the speed of the electrons from the MCP to the
screen isn't all that fast.

-Chuck Harris

Ed Breya via Groups.Io wrote:
I see that possibly adding correction magnets to fix the problem has been
mentioned here somewhat. Here's another idea, that may seem far-fetched, but not
impossible: What if the 2467 CRTs originally did have small tweaking magnets
attached, to assist in geometry. What if the adhesive or tape or whatever used
became ineffective after many years, and let go, so the magnets would come loose
and stick somewhere, like inside the mu shield? t wouldn't be obvious, because it
wouldn't be rattling around loose inside the scope.

Has anyone seen any sign of magnetic assistance on these CRTs, or anything in the
manuals, etc? Just wondering.

One other far-fetched one: Is there any possibility of the trace rotation coil
popping out of place, putting it off-axis?

Ed
Re: 2467B geometry

 

How about the -1kV supply to the PDD electrode? It is regulated mostly by four series 200 volt zeners. If one of those were shorted, it would lower that supply and affect the geometry adjustment. You can check it on J4391 on the A9 HV board.

Regards

On 3/13/2019 9:54 PM, Chuck Harris wrote:
I tried pulling the plug on trace rotation, and on
y-axis rotation, and the only effect was the trace
rotated one line width clockwise.

I guess that eliminates them, and any fringing effects
from the current in their shielded wires as they pass
down the CRT's funnel section under the mumetal shield.

What I am seeing is pretty much exactly what I would
expect to see if the box lens got moved off axis a little
bit. A hard hit on the bottom (top?) of the scope might
do that, I suppose.

-Chuck Harris

Chuck Harris wrote:
I did take the CRT out, and did not see anything
rattling about inside the shield, but it is possible
that a magnet could be stuck up in there somewhere.

The trace rotation could be eliminated by pulling
its plug. I have been meaning to try that, but
keep forgetting.

If you hold a magnet anywhere near the screen, the
trace moves drastically. Which you might expect
as the speed of the electrons from the MCP to the
screen isn't all that fast.

-Chuck Harris

Ed Breya via Groups.Io wrote:
I see that possibly adding correction magnets to fix the problem has been mentioned here somewhat. Here's another idea, that may seem far-fetched, but not impossible: What if the 2467 CRTs originally did have small tweaking magnets attached, to assist in geometry. What if the adhesive or tape or whatever used became ineffective after many years, and let go, so the magnets would come loose and stick somewhere, like inside the mu shield? t wouldn't be obvious, because it wouldn't be rattling around loose inside the scope.

Has anyone seen any sign of magnetic assistance on these CRTs, or anything in the manuals, etc? Just wondering.

One other far-fetched one: Is there any possibility of the trace rotation coil popping out of place, putting it off-axis?

Ed
Re: 2467B geometry

Chuck Harris
 

I tried pulling the plug on trace rotation, and on
y-axis rotation, and the only effect was the trace
rotated one line width clockwise.

I guess that eliminates them, and any fringing effects
from the current in their shielded wires as they pass
down the CRT's funnel section under the mumetal shield.

What I am seeing is pretty much exactly what I would
expect to see if the box lens got moved off axis a little
bit. A hard hit on the bottom (top?) of the scope might
do that, I suppose.

-Chuck Harris

Chuck Harris wrote:

I did take the CRT out, and did not see anything
rattling about inside the shield, but it is possible
that a magnet could be stuck up in there somewhere.

The trace rotation could be eliminated by pulling
its plug. I have been meaning to try that, but
keep forgetting.

If you hold a magnet anywhere near the screen, the
trace moves drastically. Which you might expect
as the speed of the electrons from the MCP to the
screen isn't all that fast.

-Chuck Harris

Ed Breya via Groups.Io wrote:
I see that possibly adding correction magnets to fix the problem has been mentioned here somewhat. Here's another idea, that may seem far-fetched, but not impossible: What if the 2467 CRTs originally did have small tweaking magnets attached, to assist in geometry. What if the adhesive or tape or whatever used became ineffective after many years, and let go, so the magnets would come loose and stick somewhere, like inside the mu shield? t wouldn't be obvious, because it wouldn't be rattling around loose inside the scope.

Has anyone seen any sign of magnetic assistance on these CRTs, or anything in the manuals, etc? Just wondering.

One other far-fetched one: Is there any possibility of the trace rotation coil popping out of place, putting it off-axis?

Ed
Re: 2246 no display/odd behavior

tom jobe
 

Hi Matt,
Did you check the various low voltage supplies before you took the power supply out of your 2246?
Knowing what the individual voltages are, and knowing how much ripple is present on them will go a long way toward pointing you to the actual problem(s).
The Tekscopes Message Archive has lots of information about these 224x scopes and their common problems.
Do a search of the message archive on various terms like 2246, 2246A, 2245, etc
tom jobe...

On 3/13/2019 5:40 PM, Matt wrote:
Thank you for the manual link. I will review the front panel function and see what I come up with. The trigger lights to not flash any codes on startup (if I do a reboot after I get the panel to come to life).

I took the SMPS out for a visual inspection. Nothing obviously fried and no signs of electrolyte on the board. I think my next step will be to measure ESR of the electros and see what I find.

Battery on the logic board measured ~75mV. I think that counts as dead. But can that be the cause of these issues?

Any further suggestions welcome as well.
WTB 012-0648-00 6 pin LEMO M-M 30" cable for Tracking Generator

 

I got my TR502 Tracking Generator, DC508 Option 7, and TM503 Option 7 all
set up and I then discovered I need the 6 pin LEMO cable (3 male pins and 3
female pins) that goes from the Spectrum Analyzer to the TR502 Tracking
Generator Logic .

The part number is 012-0648-00.

If anyone has one for sale please contact me OFF LIST at dennis at ridesoft
dot com.



Thank you,

Dennis Tillman W7PF
Re: Looking for Sony-Tektronix 318 Logic Analyser Operator's Guide

 

On Wed, 13 Mar 2019 17:04:55 -0700, you wrote:

Hi Chuck:
Thanks for letting me know.
I saw that about the 308 does it (from Tekwiki).. page 1, and page 78, in the 308 operator guide/instruction manual.
Signature analysis is built into the 308... you don't need the word recognizer probe/module accessory, to do it (at least by the page 78 example.)
Does anyone know if the 318 or 338 do signature analysis (I didn't see that in their manuals)?
Will any of the later Tek LAs do signature analysis?
Since I only have the 308, I can't say about the tektronix ones.

However, HP makes things in the 5000 series (such as a 5005B) that are
signature analyzers, and peak reading voltmeters...

Harvey


Best regards.
Re: 2467B geometry

Chuck Harris
 

I did take the CRT out, and did not see anything
rattling about inside the shield, but it is possible
that a magnet could be stuck up in there somewhere.

The trace rotation could be eliminated by pulling
its plug. I have been meaning to try that, but
keep forgetting.

If you hold a magnet anywhere near the screen, the
trace moves drastically. Which you might expect
as the speed of the electrons from the MCP to the
screen isn't all that fast.

-Chuck Harris

Ed Breya via Groups.Io wrote:

I see that possibly adding correction magnets to fix the problem has been mentioned here somewhat. Here's another idea, that may seem far-fetched, but not impossible: What if the 2467 CRTs originally did have small tweaking magnets attached, to assist in geometry. What if the adhesive or tape or whatever used became ineffective after many years, and let go, so the magnets would come loose and stick somewhere, like inside the mu shield? t wouldn't be obvious, because it wouldn't be rattling around loose inside the scope.

Has anyone seen any sign of magnetic assistance on these CRTs, or anything in the manuals, etc? Just wondering.

One other far-fetched one: Is there any possibility of the trace rotation coil popping out of place, putting it off-axis?

Ed
2246 no display/odd behavior

 

Thank you for the manual link. I will review the front panel function and see what I come up with. The trigger lights to not flash any codes on startup (if I do a reboot after I get the panel to come to life).

I took the SMPS out for a visual inspection. Nothing obviously fried and no signs of electrolyte on the board. I think my next step will be to measure ESR of the electros and see what I find.

Battery on the logic board measured ~75mV. I think that counts as dead. But can that be the cause of these issues?

Any further suggestions welcome as well.
Test input for an SD-32 sampling head

 

How do you test these? The 7 pS rise time is a pretty difficult spec if you want a 10x margin.

I'm contemplating a mercury wetted reed relay, but even that looks to be 2-3 pS at best.

I just received a couple of SD-22s and at 23 pS those are too fast for my pulser from Leo Bodnar. It's really all Leo's fault for sending plots from his CSA803 with the unit. I managed to get an 11801 with an E5622 error for $185 shipped and a pair of SD-22s for $150 shipped. The latter came today. The 11801 is supposed to arrive Friday.

I don't really need it, but an SD-30 or SD-32 would be kind of neat to have. I plan to get an SD-24 to augment the SD-22s.

Unfortunately no one in the US has fresh NVRAM and won't until June.

Reg
Re: Looking for Sony-Tektronix 318 Logic Analyser Operator's Guide

 

Hi Chuck:
Thanks for letting me know.
I saw that about the 308 does it (from Tekwiki).. page 1, and page 78, in the 308 operator guide/instruction manual.
Signature analysis is built into the 308... you don't need the word recognizer probe/module accessory, to do it (at least by the page 78 example.)
Does anyone know if the 318 or 338 do signature analysis (I didn't see that in their manuals)?
Will any of the later Tek LAs do signature analysis?
Best regards.
Re: 2247A PSU Troubleshooting

 

The common faults and solutions to the power supplies on ALL the 22xx scopes are in the archives of this group. seriously this group goes over the same stuff repetitively :)
The 2246 (applies to the 2247) power supply can be removed from the scope and using the fan as a load can be tested as a unit.(With care! this is a mains potential switching supply).
Common failure on these is C2210 4.7uF and in many cases that's all, but if you are unlucky then Q2209/10 which if I remember correctly are TIP32C, following on in the unlucky stakes the mosfet Q2214.
The secondary diodes are rarely at fault, mostly schottky so reading low on diode ranges. and in my opinion the secondary 3 leg caps are reliable.
If testing the board watch out for a bite from J2208 long after you power off! (Near the multiplier, drain it with a 100k resistor). Rarely T2204 fails, also I've had the multiplier fail, (Disconnect its input to confirm).
Re: 2247A PSU Troubleshooting

 

On Wed, Mar 13, 2019 at 08:59 PM, Nicholas Keller wrote:


So if I understand correctly, I
can connect the DUT to the isolation transformer using all three prongs.
That is correct.

Raymond
53441 - 53460 of 208699