Date   
Re: 11801 bug fixes

Albert Otten
 

On Mon, Oct 28, 2019 at 09:52 PM, Reginald Beardsley wrote:


F4 F4 F4 F4 F4 F4 34 41 | . . . . . . 4A
63 71 20 34 00 F4 F4 F4 |cq 4 . . . .
F4 F4 F4 F4 34 41 63 71 |. . . .4Acq
20 35 00 F4 F4 F4 F4 F4 |5 . . . . . . .
F4 4F 34 41 63 71 20 36 |. . 4Acq 6
Hi Reg,

The 11801 has other chips than the later types (letter suffix). Also it seems the 11801 and CSA803 don't have factory set calibration constants.

If you start dumping memory from 0x1DD70 in 0x60 byte blocks you can read the names of the routines in the diagnostic manual.
IIRC I couldn't find those names in the CSA803(A), probably because some memory bank switching is needed.

Albert

Re: HV Probe and DMM Input Impedance

Bruce Griffiths
 

Likely intended for use with a Heathkit VTVM or similar which had an 11M input R (!M in standard probe tip) 10M in internal divider. Once the HV probe is substituted for the standard probe rge scaling is effectively 100x compared to when standard peobe is used.

Bruce

On 29 October 2019 at 02:47 n4buq <n4buq@...> wrote:


BTW, this is what the probe looks like:

https://www.etsy.com/hk-en/listing/491393770/eico-high-voltage-uni-probe

Not sure, but it appears the one pictured has a scale factor of 106 (as stated on the home-made label when used with a 10M ohm meter) so maybe that's more the case (e.g. not exactly a 100:1 divider when used that way)?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "n4buq" <n4buq@...>
To: TekScopes@groups.io
Sent: Monday, October 28, 2019 8:36:37 AM
Subject: [TekScopes] HV Probe and DMM Input Impedance

This last weekend, I found an EICO HV probe in very nice condition at an
estate sale. Opening it up, it contiains a 1.09G ohm resistor in series
with the tip and cable. I connected it to the input of my Fluke 27 DMM and
measured a low voltage source (all I had handy at that moment). From what I
could tell, the probe gives me a 100x scale factor (e.g 10VDC measured
0.1VDC). While I may need to measure some higher voltages to confirm
whether this is really accurate, it appears to be at least somewhat
accurate.

I have a question, though, regarding the theory of the way this works. The
Fluke has a 10M ohm input resistance which, if I'm thinking about this
correctly, makes the measuring circuit 1100M ohms of which 10M ohm is the
meter and the remaining resistance in the voltage divider network is the
probe's resistor; however, I'm having trouble with the math.

Intuitively, (for me, at least), to obtain a 1/100 divider, I would think
that ideally the probe resistance should be 0.990M ohms with the meter
providing the remainin 10M ohms. But I find it odd that the resistor has
that odd value which makes it seem like it was almost intended to work with
a 10M device.

If I'm not mistaken, those probes were intended to be used with a particular
device (meter) that provided the proper readings but not sure about that
either (not finding a lot of info on this probe).

Am I off base here? I know that some of the HV probes designed to work with
the Fluke are designed to connect differently and I think the meter is used
in mA mode with them but not sure about that.

Is it a false expectation that the meter give me a 1/100 reading when used
with the probe in that manner? Is it also possible that the 1090M ohm is
giving me a "close enough" with that low voltage test and the difference
would become more measurable with higher voltages?

Sorry - this should be simple but, for some reason, I can't make it make
sense to me at the moment.

Thanks,
Barry - N4BUQ




Re: 11801 bug fixes

Reginald Beardsley
 

F4 F4 F4 F4 F4 F4 34 41 | . . . . . . 4A
63 71 20 34 00 F4 F4 F4 |cq 4 . . . .
F4 F4 F4 F4 34 41 63 71 |. . . .4Acq
20 35 00 F4 F4 F4 F4 F4 |5 . . . . . . .
F4 4F 34 41 63 71 20 36 |. . 4Acq 6

Any data in the NVRAM was lost. I had pulled the battery packs off the original RAM to get it to boot. To the left of the vertical bar is the hex. To the right is the ASCII . that turned out to be a valuable clue.

From looking at the names and the diagnostic manual, I'm pretty sure it's storing the error codes for each of the subsystems. If you start dumping memory from 0x1DD70 in 0x60 byte blocks you can read the names of the routines in the diagnostic manual.

I'll also see if I can come up with a way to step the aliased ramp through all the aliases. But so far I've not seen any evidence of systematic timebase error except when it gets borked and reports ~320 ps for the calibrator or SD-24 rise time measurement.

BTW I'd had concerns about screen jitter, but that turned out to be a loose IEC connector. I had not pushed it in quite all the way.

Reg

Re: Replacing TDS540B CRT with LCD?

 

Thank you for the pointer to the simmconnlabs kit.

Unfortunately by the time that crosses the pond and has been processed by UK
Customs that comes to near as darn it 230-250 pounds, which doesn't add up
for me. Part of their cost is an FPGA which I believe I can avoid the need
for by using the VGA port to drive the LCD (though I'd need to add some
VRAM).

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Stephen
Hanselman
Sent: 28 October 2019 17:46
To: TekScopes@groups.io
Subject: Re: [TekScopes] Replacing TDS540B CRT with LCD?

David,

Look at http://simmconnlabscom.ipage.com/store/page5.html pricing is
$229.00USD - I have installed two of these in TDS540C and one, a different
kit , in a HP 8566B and they all work great. The install directions were a
bit ambiguous on what to do with the glass on the glass that was in front of
the CRT. The instructions seemed to indicate leaving it off, I didn't like
that so when I did my scope I modified the frame (very minor) so that the
glass was kept and the result is spectacular

Steve


Steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of David C.
Partridge
Sent: Monday, October 28, 2019 9:30 AM
To: TekScopes <Tekscopes@groups.io>
Subject: [TekScopes] Replacing TDS540B CRT with LCD?

I believe that this is possible given a suitable "open-frame" 6.5" monitor
panel (I assume 640*480).

So far I've failed to locate anything on eBay or AliExpress (even at silly
prices).

If anyone has a pointer to a suitable panel (ideally cheap-ish) I'd be
grateful!

Thanks
David

Re: HV Probe and DMM Input Impedance

John Gord
 

Dave,
I don't think your "add 1M to the probe" will work. The 11Meg VTVMs had 1Meg in the probe and 10Meg in the instrument, creating a 10/11 divider in normal operation. The instrument scaling compensated for that. Adding 1Meg to the HV probe will actually make the situation slightly worse. (The voltage at the hot end of the 1Meg will be 1/100th of the probe tip voltage, but the DVM is looking at the cold end of the 1Meg resistor.)
--John Gord

On Mon, Oct 28, 2019 at 09:06 AM, David M wrote:

Barry, the Eico (and other manufacturers as well) made those probes so that
the resistor could be changed to accommodate the particular VTVM or multimeter
you needed to use them with. In the case of the 1090 Meg resistor, it was to
be used with a meter having 11 Meg input resistance. That would calculate to
a 1000:1 divider.
So, to use your HV probe with a meter having a 10 Meg input, you would need to
add an additional 1 Meg resistor into the probe (or wherever you could make it
fit) so that the probe works into 11 Meg.

Cheers,
Dave M

Re: 11801 bug fixes

Albert Otten
 

Hi David,

Please inspect 0x1F09F-0x1F0BF. According to my findings these addresses contain the 33 calibrations constants in the CSA803A. I'm curious to see whether these constants are close to zero (when read as signed integer) like in my and in Gerard's case.

Albert

On Mon, Oct 28, 2019 at 05:14 PM, <junk@...> wrote:


FWIW, in my 11801B (SRAM
intact) there is nothing interesting until you reach address 0x1EF60. From
that address to 0x1FFFF seems to have legitimate data.

Re: Replacing TDS540B CRT with LCD?

Stephen Hanselman
 

David,

Look at http://simmconnlabscom.ipage.com/store/page5.html pricing is
$229.00USD - I have installed two of these in TDS540C and one, a different
kit , in a HP 8566B and they all work great. The install directions were a
bit ambiguous on what to do with the glass on the glass that was in front of
the CRT. The instructions seemed to indicate leaving it off, I didn't like
that so when I did my scope I modified the frame (very minor) so that the
glass was kept and the result is spectacular

Steve


Steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of David C.
Partridge
Sent: Monday, October 28, 2019 9:30 AM
To: TekScopes <Tekscopes@groups.io>
Subject: [TekScopes] Replacing TDS540B CRT with LCD?

I believe that this is possible given a suitable "open-frame" 6.5" monitor
panel (I assume 640*480).

So far I've failed to locate anything on eBay or AliExpress (even at silly
prices).

If anyone has a pointer to a suitable panel (ideally cheap-ish) I'd be
grateful!

Thanks
David

Re: Printing Tek knobs, some details

Magic_Smoke
 

For digital scopes (with relatively low-force knobs) I think PETG would be more than sufficient, and is much more friendly (and healthy) to print compared to ABS. I will try that if I ever find myself missing a knob.

Re: HV Probe and DMM Input Impedance

 

On Mon, Oct 28, 2019 at 11:06 AM, David M wrote:


On Mon, Oct 28, 2019 at 08:36 AM, n4buq wrote:


This last weekend, I found an EICO HV probe in very nice condition at an
estate sale. Opening it up, it contiains a 1.09G ohm resistor in series
with
the tip and cable. I connected it to the input of my Fluke 27 DMM and
measured a low voltage source (all I had handy at that moment). From what I
could tell, the probe gives me a 100x scale factor (e.g 10VDC measured
0.1VDC). While I may need to measure some higher voltages to confirm
whether
this is really accurate, it appears to be at least somewhat accurate.

I have a question, though, regarding the theory of the way this works. The
Fluke has a 10M ohm input resistance which, if I'm thinking about this
correctly, makes the measuring circuit 1100M ohms of which 10M ohm is the
meter and the remaining resistance in the voltage divider network is the
probe's resistor; however, I'm having trouble with the math.

Intuitively, (for me, at least), to obtain a 1/100 divider, I would think
that
ideally the probe resistance should be 0.990M ohms with the meter providing
the remainin 10M ohms. But I find it odd that the resistor has that odd
value
which makes it seem like it was almost intended to work with a 10M device.

If I'm not mistaken, those probes were intended to be used with a particular
device (meter) that provided the proper readings but not sure about that
either (not finding a lot of info on this probe).

Am I off base here? I know that some of the HV probes designed to work with
the Fluke are designed to connect differently and I think the meter is used
in
mA mode with them but not sure about that.

Is it a false expectation that the meter give me a 1/100 reading when used
with the probe in that manner? Is it also possible that the 1090M ohm is
giving me a "close enough" with that low voltage test and the difference
would
become more measurable with higher voltages?

Sorry - this should be simple but, for some reason, I can't make it make
sense
to me at the moment.

Thanks,
Barry - N4BUQ
Barry, the Eico (and other manufacturers as well) made those probes so that
the resistor could be changed to accommodate the particular VTVM or multimeter
you needed to use them with. In the case of the 1090 Meg resistor, it was to
be used with a meter having 11 Meg input resistance. That would calculate to
a 1000:1 divider.
So, to use your HV probe with a meter having a 10 Meg input, you would need to
add an additional 1 Meg resistor into the probe (or wherever you could make it
fit) so that the probe works into 11 Meg.

Cheers,
Dave M
OOps... I fat-fingered the "0" key, & didn't proofread my post. I should have said,,, that would calculate to a 100:1 divider.

Cheers,
Dave M

Re: 11801 bug fixes

 

On Mon, Oct 28, 2019 at 02:48 PM, Reginald Beardsley wrote:


Executive processor: 10.09
Display: 9.0
Time base controller: 10.11
Acquisition #1: 9.02
Acquisition #2: 9.02
The latest / last F/W kit I've found says 10.09 / 10.12 so if that is true there may be
one minor Time Base version later than yours.

/HÃ¥kan

Re: Printing Tek knobs, some details

KeepIt SimpleStupid
 

I found this
https://www.sculpteo.com/en/materials/

Company that can print a lot of materials including metal.

What's unique and interesting for the group is it's global presence:

"Sculpteo is a global leader in digital manufacturing based in Paris and San Francisco."

On Sunday, October 27, 2019, 8:20:53 PM EDT, EJP <esmond.pitt@...> wrote:

Have a look around thingiverse.com. There is quite a bit of Tek stuff there. I seem to remember some knobs but don't quote me.

EJP

Re: 11801 bug fixes

Chuck Harris
 

Oh well! I guess there are advantages in
ponying up extra for the "C" model.

-Chuck Harris

junk@... wrote:

My 11801B doesn't have it either. Must have been added in the later versions.



Replacing TDS540B CRT with LCD?

 

I believe that this is possible given a suitable "open-frame" 6.5" monitor
panel (I assume 640*480).

So far I've failed to locate anything on eBay or AliExpress (even at silly
prices).

If anyone has a pointer to a suitable panel (ideally cheap-ish) I'd be
grateful!

Thanks
David

Re: LCD screen for CSA803 or 1180x

junk@...
 

Reg,

I've been able to use the RS 232 interface to fetch traces and screen grabs from the unit. If you'd like the code (python scripts) I can share them with you.

Also, you might try checking/replacing BT150 on the A18 memory board. This might enable you to keep stored waveforms when powered off. My notes show the following for those:
- Lithium Poly-Carbon monoflouride, BR 2/3 A
- Potential part numbers Panasonic BR-2/3AE2P or BR-2/3AE2SP

David

Re: 11801 bug fixes

junk@...
 

Reg,

I think that the battery backed NVRAM might limited to 0x10000-0x1FFFF. If my memory serves, 0x0000-0xFFFF is volatile SRAM. FWIW, in my 11801B (SRAM intact) there is nothing interesting until you reach address 0x1EF60. From that address to 0x1FFFF seems to have legitimate data.

David

Re: 11801 bug fixes

junk@...
 

My 11801B doesn't have it either. Must have been added in the later versions.

Re: HV Probe and DMM Input Impedance

 

On Mon, Oct 28, 2019 at 08:36 AM, n4buq wrote:


This last weekend, I found an EICO HV probe in very nice condition at an
estate sale. Opening it up, it contiains a 1.09G ohm resistor in series with
the tip and cable. I connected it to the input of my Fluke 27 DMM and
measured a low voltage source (all I had handy at that moment). From what I
could tell, the probe gives me a 100x scale factor (e.g 10VDC measured
0.1VDC). While I may need to measure some higher voltages to confirm whether
this is really accurate, it appears to be at least somewhat accurate.

I have a question, though, regarding the theory of the way this works. The
Fluke has a 10M ohm input resistance which, if I'm thinking about this
correctly, makes the measuring circuit 1100M ohms of which 10M ohm is the
meter and the remaining resistance in the voltage divider network is the
probe's resistor; however, I'm having trouble with the math.

Intuitively, (for me, at least), to obtain a 1/100 divider, I would think that
ideally the probe resistance should be 0.990M ohms with the meter providing
the remainin 10M ohms. But I find it odd that the resistor has that odd value
which makes it seem like it was almost intended to work with a 10M device.

If I'm not mistaken, those probes were intended to be used with a particular
device (meter) that provided the proper readings but not sure about that
either (not finding a lot of info on this probe).

Am I off base here? I know that some of the HV probes designed to work with
the Fluke are designed to connect differently and I think the meter is used in
mA mode with them but not sure about that.

Is it a false expectation that the meter give me a 1/100 reading when used
with the probe in that manner? Is it also possible that the 1090M ohm is
giving me a "close enough" with that low voltage test and the difference would
become more measurable with higher voltages?

Sorry - this should be simple but, for some reason, I can't make it make sense
to me at the moment.

Thanks,
Barry - N4BUQ
Barry, the Eico (and other manufacturers as well) made those probes so that the resistor could be changed to accommodate the particular VTVM or multimeter you needed to use them with. In the case of the 1090 Meg resistor, it was to be used with a meter having 11 Meg input resistance. That would calculate to a 1000:1 divider.
So, to use your HV probe with a meter having a 10 Meg input, you would need to add an additional 1 Meg resistor into the probe (or wherever you could make it fit) so that the probe works into 11 Meg.

Cheers,
Dave M

Re: 11801 bug fixes

Reginald Beardsley
 

It's not included in the 11801 SAMPLING HEAD FNC'S menu.

However, I learned something about the T1331 error. According to p 391 of the diagnostics manual the T1331 error is a test of four confidence words which are written to NVRAM when the system leaves the diagnostics. So it will fail if the unit has never entered normal operating mode.

There is no mention in any of the timebase controller diagnostics about factory calibration constants. The NVRAM test preserves the contents of two areas:

0x00000 - 0x03FEF
0x13FF0 - 0x1FFFF

which amounts to 1/2 the NVRAM.

The confidence values are in 0x1FFF0 - 0x1FFF6

Reg

Re: HV Probe and DMM Input Impedance

Dale H. Cook
 

On 10/28/2019 10:08 AM, Jerry Ingordo wrote:

These HV probes we designed so that you can replace the series resistor to match the input resistance of the meter you intend to use with it.
If you are replacing a very high resistance probe resistor, especially in a high voltage prove, you need to do so with scrupulous cleanliness. Skin oil or other contaminants can adversely affect the probe by introducing a leakage path across the resistor, especially under a high voltage.
--
Dale H. Cook, Member, NEHGS, AGS, MA Soc. of Mayflower Descendants;
Plymouth Co. MA Coordinator for the USGenWeb Project
Administrator of https://plymouthcolony.net

Re: HV Probe and DMM Input Impedance

Michael A. Terrell
 

The resistor should be smooth and clean. A goo builds up on those , from
contaminants in damp air. More expensive versions encased the resistor in a
seald, glass tube to keep it clean. Back in my early days in electronics
(>50 years ago) failed 66Meg resistors in the focus circuit of color TVs
failed from humidity, nicotine and HV across their bodies. The HV attracted
the particles from smoking, and the moisture turned it into goo. Spring and
fall were busy times, replacing HV parts in tube color TVs from homes where
people smoked. We rendered to those times as 'It's Flyback Season!' in a
Daffy Duck imitation. ;-)

On Mon, Oct 28, 2019 at 10:59 AM n4buq <n4buq@...> wrote:

I do have older VTVMs (HP 410B, 410C, etc.) so I could use it with those
as well. I have an older HP probe (459A) designed to be used with those
(has a different resistor) but it's missing the spring-loaded end-cap as
well as has a different resistor value. I took a look at that one
yesterday and noticed the resistor has a rather sticky film on it. I
wonder if that was originally there to reduce the effect of arcing?

If the resistor in my "new" probe didn't have fingerprints on it before,
it does now. I'll be sure to wipe down. Thanks for the tip!

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Michael A. Terrell" <@michaelaterrell>
To: TekScopes@groups.io
Sent: Monday, October 28, 2019 9:42:01 AM
Subject: Re: [TekScopes] HV Probe and DMM Input Impedance

That probe was made for a common, TV shop grade VTVM, with a 10M input
impedance, for AC measurements. In DC mode, a 1M resistor at the probe
tip
gave a total of 11M impedance. This was done to reduce the input
capacitance which would detune RF stages, or quench an oscillator. This
was
critical while servicing the high impedances encountered on tube based
electonics.

Add 1090M to 10M, and you get 1,100M wich is 100 times the impedance with
the HV probe. Be sure there are no fingerprints on the body of that
resistor, or it may arc over under HV use.

On Mon, Oct 28, 2019 at 9:36 AM n4buq <n4buq@...> wrote:

This last weekend, I found an EICO HV probe in very nice condition at
an
estate sale. Opening it up, it contiains a 1.09G ohm resistor in
series
with the tip and cable. I connected it to the input of my Fluke 27
DMM and
measured a low voltage source (all I had handy at that moment). From
what
I could tell, the probe gives me a 100x scale factor (e.g 10VDC
measured
0.1VDC). While I may need to measure some higher voltages to confirm
whether this is really accurate, it appears to be at least somewhat
accurate.

I have a question, though, regarding the theory of the way this works.
The Fluke has a 10M ohm input resistance which, if I'm thinking about
this
correctly, makes the measuring circuit 1100M ohms of which 10M ohm is
the
meter and the remaining resistance in the voltage divider network is
the
probe's resistor; however, I'm having trouble with the math.

Intuitively, (for me, at least), to obtain a 1/100 divider, I would
think
that ideally the probe resistance should be 0.990M ohms with the meter
providing the remainin 10M ohms. But I find it odd that the resistor
has
that odd value which makes it seem like it was almost intended to work
with
a 10M device.

If I'm not mistaken, those probes were intended to be used with a
particular device (meter) that provided the proper readings but not
sure
about that either (not finding a lot of info on this probe).

Am I off base here? I know that some of the HV probes designed to work
with the Fluke are designed to connect differently and I think the
meter is
used in mA mode with them but not sure about that.

Is it a false expectation that the meter give me a 1/100 reading when
used
with the probe in that manner? Is it also possible that the 1090M ohm
is
giving me a "close enough" with that low voltage test and the
difference
would become more measurable with higher voltages?

Sorry - this should be simple but, for some reason, I can't make it
make
sense to me at the moment.

Thanks,
Barry - N4BUQ