Date   
Re: 11801 NVRAM

Albert Otten
 

On Tue, Sep 17, 2019 at 02:52 PM, Chuck Harris wrote:


I was just reading the 11801C manual, and it states on
page 2-6:
[---]
o Time Base Cal Constants (these are regenerated
automatically if lost)
Are you sure Chuck? The CSA803C service manual says at the same page 2-6:
o some of the Time Base Cal Constants (these are regenerated automatically if lost)
I don't have the 11801C manual (the Tekwiki link reports missing).
Albert

Re: 11801 NVRAM

Chuck Harris
 

Hi Sergey,

You sound like me... great ambition, limited time.

I have copied the display EPROMS, and the exec EPROMS.

I am not sure where the TB EPROMS are, but if they are
nestled up behind the sampling heads, I have no interest
in going there.

The 11801C and CSA803C share the same documentation... so
the differences in the "C" models appear to be just foot
notes, for the most part.

I cant say what the CSA "A" model has or doesn't have that
the 11801"C" model has or doesn't have. I would expect
that the suffix letters between the 11801's and CSA's are
probably the same.

After all, aren't the CSA's just 11801's with clipped wings?

My 11801C is above B030000, and it mentions the OPT 1T in
the Identify page. So, the manual is true on that point.
I suspect tek just bundled it in with the rest of the
code after the B020000 check point.

-Chuck Harris

Sergey Kubushyn wrote:

On Tue, 17 Sep 2019, Chuck Harris wrote:

Hi,

Yes, it might be. Good to have EEPROMs copy anyway. I don't also know what
ROM versions are in my 11801C and it is in my own far storage corner on a
shelf so it would take quite an effort to get there and check. Have too many
stuff and in major remodeling (?) now -- lots of construction work, finally
installing my lathe/mills/breke/sheet metal tools/machinery and so on...
Unfortunately it is not something quick and as a matter of fact can take
forever -- it is impossible to complete, one can only stop that process at
some point :)

I do remember that 11801C has everything CSA803A had and more by default but
not sure if it applied to all of them or starting at some serial number. And
that "Option" noun is that bothers me...

Hi Sergey,

I am getting ready to do some EPROM copying, and was looking for
parts information... which is sadly missing from my manual.

I did run across a little bit on instrument options that states
option 1T is standard after serial B020000, as is my machine, but
still shows up in the identify pop up menu. This option can be
added to pre B020000 instruments.

So, we may be chasing nothing.

-Chuck Harris

Re: 11801 NVRAM

Chuck Harris
 

I quoted the 11801C directly. So I am only sure
what the manual says.

You can get the manual from Didier's site. He has
sections for the CSA803C, and the 11801C. There is
some duplication.

But the 11801C is in /Tektronix/Tektronix - 11801 Digital
Sampling Oscilloscope

Just use his search to look for "11801C"

-Chuck Harris

Albert Otten wrote:

On Tue, Sep 17, 2019 at 02:52 PM, Chuck Harris wrote:


I was just reading the 11801C manual, and it states on
page 2-6:
[---]
o Time Base Cal Constants (these are regenerated
automatically if lost)
Are you sure Chuck? The CSA803C service manual says at the same page 2-6:
o some of the Time Base Cal Constants (these are regenerated automatically if lost)
I don't have the 11801C manual (the Tekwiki link reports missing).
Albert

Re: 11801 NVRAM

Sergey Kubushyn
 

On Tue, 17 Sep 2019, Chuck Harris wrote:

Hi Sergey,

You sound like me... great ambition, limited time.
Eh... That't the only thing that is in very short supply, time... It is
something one can't buy :(

I have copied the display EPROMS, and the exec EPROMS.

I am not sure where the TB EPROMS are, but if they are
nestled up behind the sampling heads, I have no interest
in going there.
OK, that would've been very interesting to have. I will do the same for my
11801C when I had chance to get to it. It is fully working, I did test it
with SD-24 taking some TDR measurements but I don't remember what serial
number it is... I do also have 11802B that I purchased cheap for its very
fast calibrator and built-in delay line, was contemplating making some
hybrid of that and my 11801C but that is probably not a viable idea as that
delay line limits bandwidth rather bad. I do have a standalone one, DL-11 or
whatever it is called but one can clearly see it is not all that high
bandwidth -- it has SMA connectors on it.

The 11801C and CSA803C share the same documentation... so
the differences in the "C" models appear to be just foot
notes, for the most part.

I cant say what the CSA "A" model has or doesn't have that
the 11801"C" model has or doesn't have. I would expect
that the suffix letters between the 11801's and CSA's are
probably the same.
Ah, I meant CSA803C... I'm not very familiar with CSA803x, just know they
have 2 handicapped head slots providing power only unlike 11801C that has
all 4 slots fully functional. There might be a use for power-only slot for
e.g. SD-51 but otherwise it is just a handicapped 11801x...

After all, aren't the CSA's just 11801's with clipped wings?

My 11801C is above B030000, and it mentions the OPT 1T in
the Identify page. So, the manual is true on that point.
I suspect tek just bundled it in with the rest of the
code after the B020000 check point.

-Chuck Harris

Sergey Kubushyn wrote:
On Tue, 17 Sep 2019, Chuck Harris wrote:

Hi,

Yes, it might be. Good to have EEPROMs copy anyway. I don't also know what
ROM versions are in my 11801C and it is in my own far storage corner on a
shelf so it would take quite an effort to get there and check. Have too many
stuff and in major remodeling (?) now -- lots of construction work, finally
installing my lathe/mills/breke/sheet metal tools/machinery and so on...
Unfortunately it is not something quick and as a matter of fact can take
forever -- it is impossible to complete, one can only stop that process at
some point :)

I do remember that 11801C has everything CSA803A had and more by default but
not sure if it applied to all of them or starting at some serial number. And
that "Option" noun is that bothers me...

Hi Sergey,

I am getting ready to do some EPROM copying, and was looking for
parts information... which is sadly missing from my manual.

I did run across a little bit on instrument options that states
option 1T is standard after serial B020000, as is my machine, but
still shows up in the identify pop up menu. This option can be
added to pre B020000 instruments.

So, we may be chasing nothing.

-Chuck Harris
---
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Re: Tektronix 7854 Digitization Issue

Kyle Rhodes
 

I've had some success! Adjusting the Good Sample Flip Flop seems to be the
ticket. In B5 on page 4-50 of the service manual it has one adjust R102 by
reading some voltages to start with -- this did not work for me. But,
attaching the scope as starting in step 'L', I was able to see the waveform
and I adjusted R102 until the signal looked good and triggered well.

However, I think I was a bit over-zealous in putting the covers back on, as
while the waveform acquires much better now, I am seeing some strange
behavior at the end of the waveform -- namely, it tends to zero out for
0.5-1 divisions. I suspect I can fix this with some more careful
adjustment of the GSF signal pot, as I don't recall it doing this in the
past.

I started from the beginning of the Z-axis calibration on 4-47. My initial
voltage was 30V high, so I got that taken care of.

Though, in B4 "Adjust Z-axis Transient Response) on 4-49 I had some
trouble. I could not for the life of me get C150, R150, C155, and R155 to
do much of anything. They all already were pegged as well, so not sure if
someone else tried in the past too. Not sure if this affects digitization
stuff at all, or just analog display? I need to look at the schematics in
more detail...

Furthermore, it appears I need to look into calibration, as when I was
paying close attention to signal amplitudes and periods during testing, I
noticed some things are off.

And, shall I say, this scope is a beast! What incredible engineering went
into it....


Thanks,
Kyle

On Tue, Sep 17, 2019 at 10:49 AM Albert Otten <aodiversen@...>
wrote:

Hi Raymond,

You are right! I misinterpreted the function of the GSF (a little bit
stupid since the vertical signal I referred to is not at all involved
here). Apparently the blanking signal is included already by the Z-axis
controller and not a separate signal to the Z-axis amplifier.
Well, this will be a relief for the OP.

Albert
On Tue, Sep 17, 2019 at 03:21 PM, Raymond Domp Frank wrote:


Albert,

On Tue, Sep 17, 2019 at 01:53 PM, Raymond Domp Frank wrote:


Of course, I don't remember exactly which one...
It's the GSF (Good Signal Flip-flop) trimmer (U102) on the Z-axis board
(dwg
13). See description of Digitiser Control Logic > Bus Control > Internal
Acquire Mode, page 2-61 in my manual (070-2874-01), Jan '82. Also, see
Table
2-8 on page 2-122 and are F,G-2 in dwg 21.

Raymond


Re: Tektronix 7854 Digitization Issue

 

On Tue, Sep 17, 2019 at 01:40 PM, Albert Otten wrote:


.....the GSF signal which inhibits digitizing/storage of extreme Y values.
This reminded me of the ancient but quite nice Philips PM3320A/3323A/3340A digital sampling 'scopes: They have separate adjustments to suppress excursions of the trace beyond defined left, right, top and bottom positions by blanking.

Raymond

Transistor solder dwell time

DW
 

I have reinstalled Q384 and Q386 transistors onto the main board of the 577 but upon soldering them back in they became fairly hot to the touch which had me concerned as I know heat is the enemy of electronics. When I removed them a fair amount of heat was involved due to the length of the leads being used on the pads, the soldering tool helped here and it appears these transistors survived the somewhat difficult removal after checking with a multimeter.

So my concern here is dwell time installing and removing transistors, especially the difficult ones which might require multiple attempts to desolder the leads and pull it out, I wonder if they make a 3 iron soldering gun in this case so all 3 leads can get heated and it can quickly be removed?

Thanks

Re: 11801 NVRAM

Albert Otten
 

For the 11801C it only lists user and programmer manuals, not the service manual.
Albert

On Tue, Sep 17, 2019 at 05:49 PM, Chuck Harris wrote:


I quoted the 11801C directly. So I am only sure
what the manual says.

You can get the manual from Didier's site. He has
sections for the CSA803C, and the 11801C. There is
some duplication.

But the 11801C is in /Tektronix/Tektronix - 11801 Digital
Sampling Oscilloscope

Just use his search to look for "11801C"

-Chuck Harris

Albert Otten wrote:
On Tue, Sep 17, 2019 at 02:52 PM, Chuck Harris wrote:


I was just reading the 11801C manual, and it states on
page 2-6:
[---]
o Time Base Cal Constants (these are regenerated
automatically if lost)
Are you sure Chuck? The CSA803C service manual says at the same page 2-6:
o some of the Time Base Cal Constants (these are regenerated automatically
if lost)

I don't have the 11801C manual (the Tekwiki link reports missing).
Albert

Re: Transistor solder dwell time

Glenn Little
 

Eliminate the question and get proper desoldering equipment.
PACE makes very good desoldering equipment and it is available on EBay reasonable.
Hakko also makes good equipment.
These will not damage the boards nor the parts.
It will take some practice on junk boards, but it is well worth it if you repair electronics.

Glenn

On 9/17/2019 1:22 PM, DW wrote:
I have reinstalled Q384 and Q386 transistors onto the main board of the 577 but upon soldering them back in they became fairly hot to the touch which had me concerned as I know heat is the enemy of electronics. When I removed them a fair amount of heat was involved due to the length of the leads being used on the pads, the soldering tool helped here and it appears these transistors survived the somewhat difficult removal after checking with a multimeter.

So my concern here is dwell time installing and removing transistors, especially the difficult ones which might require multiple attempts to desolder the leads and pull it out, I wonder if they make a 3 iron soldering gun in this case so all 3 leads can get heated and it can quickly be removed?

Thanks


--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

Re: PM for a working Tek 577 with D1 storage Curve Tracer

Kevin Oconnor
 

So Chuck, regarding #1, I almost never use storage. That being said, I was unaware
one could do damage with it off. I’ve had this CT almost 40 years. But I can always learn something new. Don’t keep me in suspense!

K - KO3Y

Re: 11801 NVRAM

Reginald Beardsley
 

The TB ROMS are on the A5 board which is on the bottom. So it only requires turning it upside down and removing the bottom cover. The ROMS are next to the NVRAM. I'd like to ask that you also note the board part number if you copy them. That would actually be useful for all ROM images just in case the model differences are just FW.

BTW All the large lithium batteries on mine have 88-89 date codes and read around 3.1 V IIRC. The NVRAM batteries die because they are around 35-45 mAh capacity.

I ran a bunch of other tests this morning with the 100 kHz ramp and trigger 1mHz apart. That gave me a flat line that slowly moved up the screen. I used a 1 Vpp ramp and the 2 mV/div scale. Any timebase errors are less than vertical amplifier noise. Based on my tests and the manual information, I think the "lost factory calibration" problem is mythical.

When I get my other 11801x from CA I'll examine the operation of the timebase more closely. In particular, I want to investigate using one of Leo's GPSDOs in place of the OXO which is not as stable as the TCXO in the 33622A. The OTCXO option for the 33622A must be really awesome if the TCXO is that good. I've compared it to Leo's GPDSO and it's *very* stable and accurate. Amazing what people manage to accomplish with 30 years of engineering effort.

I'd love to know what the substantive differences are in the 11801 series. An 11801C *might* be worth getting if there are significant changes. But a color screen is not of interest to me. I looked at the 11801C specifications this morning and did not see anything I recognized as different from my 11801.

After several days of fun with the 11801 I'm going to return to my originally scheduled project of hacking the FW on the nanoVNA. It's not as just pure amazing as an 11801, but in the bang for the buck department it's like the $20 LCR-transistor testers and $10 DMMs. If only they had existed 40 years ago.

The STM32F072CBT6 only has 16 KB of RAM and 128 KB of flash, so it's rather limiting. But I think that by rewriting the FW to eliminate threading, Smith chart, etc I can implement TDR and SWR. In a sub $50, self contained, portable unit that would be extremely useful for antenna and feedline work.

Have Fun!
Reg

Re: Circuit boards used to demo scopes\ c]

Dave Seiter
 

You could build at least two of them.  I did years ago from schematics posted either in the archive or referenced to someone's site.  
-Dave

On Tuesday, September 17, 2019, 05:55:19 AM PDT, Marvin Moss <mmoss@...> wrote:

Does anyone have extra circuit boards they would sell me for the waveform and pulse generators used to
demonstrate how well a TEK scope would sync and show waveforms.
They were just plain boards without a case and usually run by a 9 volt battery.
Please send me the board number if you don't mind.

Re: Transistor solder dwell time

Harvey White
 

There's several things to consider, one of which is that in the data sheet, there's a max temperature for the leads and time when soldering.  It's much worse with SMT parts because of the short lead length.

Is there a custom soldering tip used for desoldering?  yes, lots of them, mostly for SMT stuff that I've seen but there used to be some.  Main problem is that they were not used in a temperature controlled iron, which you really want.  You mentioned soldering gun.  Those are generally good for soldering metal parts together, but I would never use one for electronics.

You might want to look at Weller, Ungar, Hakko for ideas of what tips are available and what use they are intended for.  Most transistors are capable of withstanding temperatures on the case hot enough to burn, but with epoxy transistors, it's not going to be as obvious.

If you had a temperature controlled iron and a number of tips, you could likely make a custom desoldering tip using some sheet copper and some creative filing, and that's if you can't find anything.

Harvey

On 9/17/2019 1:22 PM, DW wrote:
I have reinstalled Q384 and Q386 transistors onto the main board of the 577 but upon soldering them back in they became fairly hot to the touch which had me concerned as I know heat is the enemy of electronics. When I removed them a fair amount of heat was involved due to the length of the leads being used on the pads, the soldering tool helped here and it appears these transistors survived the somewhat difficult removal after checking with a multimeter.

So my concern here is dwell time installing and removing transistors, especially the difficult ones which might require multiple attempts to desolder the leads and pull it out, I wonder if they make a 3 iron soldering gun in this case so all 3 leads can get heated and it can quickly be removed?

Thanks



Re: Transistor solder dwell time

DW
 

Thanks for the reply and very good point

I agree with you that that it does make all the difference with proper soldering equipment. I started out on a Radio Shack 10W soldering iron, it took 10 minutes to warm up but then eventually would get to hot and burn the solder, soldering with it was doable but a hassle, I had it and used it because it was conveniently laying around at the time. I have since then upgraded to a Hakko desoldering station and a Hakko desoldering gun, though not cheap they were well worth the cost and changed my experience with soldering making me more effective, especially with practice as you mentioned . I feel at least I am on the right track though it still appears that I could have done things better I am admitting to.

Re: Transistor solder dwell time

Dave Seiter
 

BTDT!  I have a "tip" that has a two inch wide working surface; don't recall what I used it for, but it took forever to heat up.
-Dave
---------------
 make a custom desoldering tip using some sheet copper and some 
creative filing,

Re: 11801 NVRAM

Chuck Harris
 

It is mislabeled: 11801 Sampling Oscilloscope Operation and service 070-9972-02

-Chuck Harris

Albert Otten wrote:

For the 11801C it only lists user and programmer manuals, not the service manual.
Albert

On Tue, Sep 17, 2019 at 05:49 PM, Chuck Harris wrote:


I quoted the 11801C directly. So I am only sure
what the manual says.

You can get the manual from Didier's site. He has
sections for the CSA803C, and the 11801C. There is
some duplication.

But the 11801C is in /Tektronix/Tektronix - 11801 Digital
Sampling Oscilloscope

Just use his search to look for "11801C"

Re: Transistor solder dwell time

Jamie Ostrowski
 

I have used those clamp-on hemostat needle-nosed type tool in the past to
act as a heat sink on the leads when I'm soldering/desoldering. Cheap and
seemed to work well. Might that be helpful?

On Tue, Sep 17, 2019 at 1:54 PM Dave Seiter <d.seiter@...> wrote:

BTDT! I have a "tip" that has a two inch wide working surface; don't
recall what I used it for, but it took forever to heat up.
-Dave
---------------
make a custom desoldering tip using some sheet copper and some
creative filing,



Re: Transistor solder dwell time

DW
 

"I have used those clamp-on hemostat needle-nosed type tool in the past to act as a heat sink"

I think you just gave me an idea, perhaps take a square piece of metal drill a hole in it and bolt it down with thermal compound, and when I solder the metal piece will help absorb the heat from the transistor. Maybe put it in the freezer to help even more. Well if anything I might have given someone an idea about something.

Re: Transistor solder dwell time

DW
 

I should mention how valuable a helpings hands tool can be, it frees up your hands and allows you to precisely position a component for soldering, and you don't burn your fingers.

Re: 11801 NVRAM

Albert Otten
 

Thank you Chuck for that hint!
Very strange, those few words "some of the" omitted in the 11801C service manual while present in the CSA803C service manual. Probably an unintended omission since the warning at p. 6-108 about loss of factory set calibration constants is present (and same as in CSA803C).

Albert

On Tue, Sep 17, 2019 at 09:33 PM, Chuck Harris wrote:


It is mislabeled: 11801 Sampling Oscilloscope Operation and service
070-9972-02

-Chuck Harris

Albert Otten wrote:
For the 11801C it only lists user and programmer manuals, not the service
manual.
Albert

On Tue, Sep 17, 2019 at 05:49 PM, Chuck Harris wrote:


I quoted the 11801C directly. So I am only sure
what the manual says.

You can get the manual from Didier's site. He has
sections for the CSA803C, and the 11801C. There is
some duplication.

But the 11801C is in /Tektronix/Tektronix - 11801 Digital
Sampling Oscilloscope

Just use his search to look for "11801C"