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On Fri, Nov 27, 2020 at 07:25 AM, Oz-in-DFW wrote:

If the crack is at a mechanical stress location you'll want to use a small
jumper that terminates outside the stress zone and is formed to survive the
stress source (like a bend or repeated motion.) I have some 17 strand silver
plated 30 AWG teflon wire that I use for this kind of thing.

Thank you all for your interest and replies.

/g/TekScopes/album?id=257176
I added some more pictures and there are duplicates that show the crack across some of the traces. Duplicate pictures I tried to remove but unable to figure out how so I will leave them up for now. (Maybe Dennis could help me with this correction)

Yes this is at a stress location but I think the bend location can be changed. I scraped away at the protective covering carefully at two spots on a trace to see what was used as the conductor. It does look like a glass which is impossible to scrap at it without getting rid of the conductor also. The conductive epoxy looks like a good solution. But I was also thinking if I could locate a terminal that has the sharp pins that could penetrate thru the trace as was original used to attach the metal terminal to the trace then I could use that as a bridge.

A friend brought me the remains of three partially cannibalized 564 scopes
once. I built one out of the three corpses. He was a contract broadcast
engineer, but he wouldn't touch test equipment that needed repairs. Over
the years he has sent a lot of repairable equipment to the landfill. Things
like dozens of probes for Boonton 92 meters. when the meter didn't work
with any of them. The probes are repairable, and the cables are expensive.
Some people! They were easily worth a couple grand, back then.

Hey Steve,

I didn't read the code in detail, but it looks to me that the firmware
dump and write is done with what looks like binary reads and writes. From
what I understand or remember, the scope has to be in "unprotected" mode,
and then you use this binary protocol to read and write from the scope's
memory. See
(-friends)-firmware-reverse-engineering/msg1170142/#msg1170142
.
There is however another way this could be done, I think, though it's sure
to be painfully slow. If you look at this thread,
,
it mentions the WORDCONSTANT:ATPUT command. I seem to remember there's a
complementary :ATGET or the like - I remember playing with this back when I
messed with the options on my TDS784D.
Knowing the address space layout on the scope, it should be possible to
read back the firmware byte by byte or word by word through this command.
Going to be dog slow, though.

Have fun,
Siggi

On Fri, Nov 27, 2020 at 11:31 AM Steve Hendrix <SteveHx@...>
wrote:

Thank you for trying to help, but none of those
links work for me to actually find the commands
needed over GPIB to dump the ROMs. Any other hints?

Steve Hendrix

At 2020-11-24 01:30 PM, you wrote:

Hey again,

maybe this helps:

?

Siggi

On Tue, Nov 24, 2020 at 1:28 PM Sigur?°ur ?&#65533;sgeirsson <

siggi@...> wrote:

Hey Steve,

there's a thread about this on EEVBlog:

(-friends)-firmware-reverse-engineering/50/
.

Sadly it looks like the github repository linked is no more, though
searching for "tekfwtool" does turn up some results. I didn't look any
closer at those results.

Good luck,
Siggi

On Tue, Nov 24, 2020 at 12:32 PM Steve Hendrix <

SteveHx@...>

wrote:

I'm still looking for instructions on the "hidden" commands to save
the ROM contents for my TDS784C, TDS220, and even my HP4263A,
HP8595E, and HP8714ET. Google hasn't turned up anything.

Steve Hendrix

At 2020-11-05 12:10 PM, Monty Montgomery via groups.io wrote:

The instructions in various places found by google searches work; any
working GPIB interface (I use a Prologix USB) works fine. No need

for

a vintage model. Password 'rambo' and off to the races...
Let me search through my bookmarks for verbatim command lines in the
event Google doesn't help you, but I warn you, I'm on Unix...

Monty

On Thu, Nov 5, 2020 at 10:24 AM Steve Hendrix
<SteveHx@...> wrote:

I've been lurking here for quite a while, and have seen lots of
discussions about saving the contents of the firmware ROMs in case
they degrade. I have programmers that go back to the early 80's,

so

can probably burn a new set if I need to. Finding an old PC that

can

run them might be problematic, but I still have an original IBM PC
with a full complement of interfaces, and it still works.

However, I

can't find any instructions in the SCPI command set for this
instrument that will dump the images. Such a command is usually a
hidden function, not advertised to the world. Can anyone here

tell me

how to dump the ROM images via GPIB?

Steve Hendrix

Thanks for the excellent description Raymond!

Two things: I checked my working scope, and the range is precisely 10.00 turns. Mine starts at 0.25(5) (5 is estimated as midway between the 5 and 6 tick marks), and ends at 0.25(5).

There is a calibration procedure in the service manual:?. I don't fully understand the procedure yet - I don't have a Time Mark Generator nor experience with one. But as Raymond described, it seems to be differential, not absolute. And I don't see (yet) an initial setting calibration. See page 5-57, item 77 through 79.

Besides twirling knobs to check functionality, I haven't had the chance to really dig back into the B timing. I'm only going off my memory of 35 years ago. So thanks again for the concise description Raymond.

Dave

Even though way off the off topic topic (parse that), still a fun discussion. I scored a box of 10 real gyros and logic pulled from DC-10s. Cute little rate gyro, etc. Problem is, all that stuff takes 28v 400Hz. Haven't gotten around to making a power supply for them yet.

On Fri, Nov 27, 2020 at 05:08 PM, Dave Peterson wrote:

Does anyone have a working setup in which the value of the Vernier can be
checked? Does it indicate time values? If so, wouldn't it have to be scaled
according to the time/div setting?

The dial shows the delay from the start of the A time base to the start of the B time base in time units selected by the number on the A time base selector (if in the cal. position). Usually, this is observed using the B trace. So, with the A time base set at e.g. 1 us/div, when changing the value on the dial from e.g. 3.61 to 4.61, the B trace moves by 1 us (if B is set to "Run after Delay"), *whatever* the setting of the B time base. The fact that the number relates to the A, and not the B time base may seem counter-intuitive at first.
Although the "delay time multiplier" knob, as it's called, is almost always used differentially, I guess the "offset" mentioned by some compensates for the absolute minimum delay (for the start of the B time base), achievable when setting the delay time multiplier knob CCW.

Raymond

" Ummm, FairRadio (in Lima, OH) has (had?) some of the more common ones in
back... - (No affiliation, just a customer)."

Thank you David. I have emailed them, as you suggest. Their web
site shows that they do have one, or more. I emailed to ask them if the
modules were complete (I did say that I can not ask them if they work, just
that they are not stripped of tubes and other parts). I'll await their
response.

They are only 6.5 hours away (lol). Once all this pandemic BS is over and
we have our President Biden manaded inoculations, I would like to take a
weekend trip out there and visit them and the big flea markets between
Dayton and Cincinnati. Sounds like a nice trip for this spring or next
summer (I pray this virus is over by then). In the meantime, I can have
them ship stuff to me.

Dave

On Wed, Nov 25, 2020 at 3:51 PM David Holland <david.w.holland@...>
wrote:

Today, with that which shall not be named still around?

Ummm, FairRadio (in Lima, OH) has (had?) some of the more common ones in
back... - (No affiliation, just a customer).

IIRC, they were in what I would at least consider fair condition. They'll
probably be kind of expensive, but you should be able to stipulate that
they have all their tubes. You'll probably want to send them an email,
their website is not at all complete.

After that, I dunno, you're back to ePay...<shrug> If anyone has any
suggestions, I'd love to hear them as well. I have a few plugins I'd like
to find. (A 3B5 particularly.)

David


On Wed, Nov 25, 2020 at 2:38 PM David Kuhn <Daveyk021@...> wrote:

If not for FleaBay, then where else can one obtain these old scope

modules?

On Wed, Nov 25, 2020 at 1:19 PM - <rrrr6789@...> wrote:

My rule of thumb when looking at electronic equipment on E-bay or
anywhere else is to look *closely* for signs that anyone has been into

it.

If it isn't *sealed* and it's not guaranteed to work then expect the
worst. I wouldn't pay more than a *minimal* price for anything that

has

been opened and that isn't guaranteed to operate properly. I've seen

far

too much equipment for sale by big time used equipment dealers such as
Tucker Electronics being sold in "as-is" condition that I'm sure have
already been stripped of anything useful.

On Wed, Nov 25, 2020 at 10:08 AM David Holland <

david.w.holland@...>

wrote:

Yeah, as Brenda said....

The manuals detail what vacuum tubes are in the plugins. I'd pay

close

attention to any photos as I've gotten burnt once or twice by not

paying

attention to them. I would presume if there's no photos, and no

statement

one way or the other, that the tubes are missing.

If you start getting into the advanced (sampling) plugins, I would

pay

closer attention to the photos for the presence of the transistors,

as

most

of them are socketed, long obsolete, and made from 99.95% pure

unobtanium.

A few plugins (ex: 3B3) use tunnel diodes, but as far as I've seen,

they're

generally soldered to the board. Tunnel diodes are also mostly made

of

unobtanium, and may be dead, but at least they'll likely still be

there...

:-)

Again, the various plugin manuals all have a relatively complete

parts

list

in the back, if you wonder what should be in a given plugin.

David


On Tue, Nov 24, 2020 at 12:05 PM Brenda via groups.io <brendda75=
[email protected]> wrote:

Hello Dave, The 3A1 plugins that I have come across ends up not

only

the

6DJ8 tubes missing, there are 2 8233 tubes that end up missing as

well.

There are 4 7586 nuvistor tubes in the front end, but seems like

the

tube

pickers pass over these from my experience. I am in the market for

a

few

3A1 and 3A6 plugins myself...at a reasonable price, $400 is just

way

too

much!!

Thank you for trying to help, but none of those links work for me to actually find the commands needed over GPIB to dump the ROMs. Any other hints?

Steve Hendrix

And the value of the DTP Vernier was irrelevant, right?

So far we have that it appears there was an initial setting by model, but no definition to the reason or significance of that value.

Does anyone have a working setup in which the value of the Vernier can be checked? Does it indicate time values? If so, wouldn't it have to be scaled according to the time/div setting?

Now that I think about it, isn't that all this dial can do? Indicate decimal values from 0.00 to 9.99? I don't think I've ever tested it turned it fully CW. Does the pot stop at 10 turns? That's kind of a rhetorical question. I'll try myself when I get in the shop. I also need to do my own homework and review the calibration procedure in the manual.

Dave

When I was a pup in the emerging field of digital data storage and field recorders, I was presented with a 465B for my bench. I remember staring at it for a minute or so, until the senior tech reached over and pulled on the power knob. I still hadn't found it...

Learned to love the 465, and still have the refurb one I bought with a loan from Grandma in the previous century, $2K

The data recorder (prefer not to say what it recorded...) used dynamic RAM with a 1mS refresh rate, and a 250 nS read cycle. Running the scope at 100 uS / Div on RAM clock the gave you a nice parade of closely spaced pulses at the left side of the screen, and over at the right side you might see the beginning of the next refresh cycle if the clock crystal in the recorder was off a bit. We would use the B-Delayed sweep to slowly scroll through the sequential addresses to the RAM, and thereby be able to see any desired address of the lower 8 bits of the bus as the address incremented.

Pretty much a similar use case as with analog TV, the variable delay allowing you to scroll to a particular line, or portion of a line, in the video scan...

_Dave KC6UPS

Looks like it's been stored in a tropical jungle for a few years!

I'm thinking just below a pigeon loft or leaky garden shed.

Priced to be sucker bait, especially given the description. He's let all the smoke out and cut the cord!

--
Oz (in DFW) N1OZ

The main feature of the photograph you provide looks more like some sort of residue to me than a crack (if I'm looking at the correct feature in the photo.). It's also not clear why a crack would develop there as it does not appear to be a flexure or stress line. The photo you provide has neither the magnification to see cracking, nor an indication of where you think the cracking has occurred.

While you may already understand that all you state is a hypothesis that needs to be proven and have made measurements to verify it, your post does not indicate you do or have. Cracking can be tricky in printed traces.
You should be able to prove your hypothesis by probing the trace. You'll want to use a rounded probe tip, or a small piece of metals as a pad so as not to damage the trace. Fix one end and drag the probe along the trace. resistance should increase steadily for a healthy trace and increase abruptly at a crack.

Most of the time when I see cracking in these kinds of older flex circuits it's at the connector pins. More often than not it's invisible without considerable magnification and careful lighting.

I've repaired these kinds of traces with conductive epoxy. If the crack is at a mechanical stress location you'll want to use a small jumper that terminates outside the stress zone and is formed to survive the stress source (like a bend or repeated motion.) I have some 17 strand silver plated 30 AWG teflon wire that I use for this kind of thing.

--
Oz (in DFW) N1OZ

Just wanted to ask again if anyone has any 70s IBM stuff. System/3, 5xxx,
etc. Old terminals. You can tell them apart because the keyboards look more
like a typewriter than a computer, and the gear is usually encased in thick
metal plating, and often comes in the form of a full desk.

Hi Steve,

Looks like your email address and the version that uses "at" and "dot"
aren't the same. Is that a typo?

Thanks,
Barry - N4BUQ

Bill,

Since this is so far off-topic, please feel free to contact me off-list:

sonodocsch@...

If this gets blocked, it is sonodoc at gmail dot com.

My interest in guidance and nav stuff is not professional but I’d guess you
would call it “hobby”. I have quite a bit of Litton stuff - a lot turned up
in the Los Angeles surplus stores since they were in Woodland Hills.

I’d be interested to discuss my interests in the G&N hardware. I’m a
radiologist by trade, but I have more books on G&N than I have books on
radiology. I am also a member of the Institute of Navigation as well as the
IEEE (well, in addition to the American College of Radiology and a few
other radiology societies).

Steve Horii

On Fri, Nov 27, 2020 at 09:38 Bill Higdon via groups.io <willard561=
[email protected]> wrote:

Is the F-111 Nav computer part of the INS system? Also the Navy boxes
might be part of an INS system. I worked at Litton in SLC back in the 70's
& worked on the Analog INS as well as the digital. The analog systems had
electro-mechanical inetegrators for all 3 axis. I left when I was told I
was going to be put on the Astro INS, in retrospect I should have stayed,
oh well.

No direct experience, but looks like a conductive ink was used.

Perhaps this, or something similar would work:



_Dave KC6UPS

For decades I have taken equipment that was discarded in disgust or stored horribly and restoring it to operation. Initially, it was because of poverty, now I get great enjoyment from rescuing it from the dumpster and solving the puzzle of it's problems. In 1971 I had returned from duty in southeast Asia to Griffiss Air Force Base in Rome, New York to finish my term. Having worked on some neat stuff, I was interested in having some of the rigs for my own. At that time, a Tektronix 524 would cost $200.00 or more, and a Collins R-390 receiver would be $500.00 . Once I got to the base, I felt certain there would be surplus stores around, and there were, in nearby Utica. Enroute to one I had been told about, I noticed piles of gear out in the open in the heaped ruins of a burned building. Some of it was totally wrecked, but most was a bit smoked up and covered with dirt and ashes. The owner was delighted to sell us anything we wanted from the ruins for very low prices. I got an R-390 for $15.00, quite literally half buried in the ground, and a friend with me got a 535 scope that was just about as bad for the same price. After an initial stop at a self service car wash to get the worst of the dirt and ashes off, we both spent many evenings and a few weekends, and a good amount of penetrating oil and contact cleaner, dismantling and cleaning the rigs. Manuals were easily obtained, I worked in the radio shop and my friend had a connection in the instrumentation lab. We were both very surprised and impressed at how well they turned out physically, indeed good enough that some of the lifers and officers gave us a lot of crap about having "misappropriated" them. Fortunately, we were both returnees from the Vietnam theater, and knew what to expect and do. We had receipts from the surplus store and pre-restoration photos. The lifers then just shrugged in disappoinment and left us alone. We both enjoyed the fruits of our work, I kept the R-390 for years, and my friend used the scope for digital experimenting and very early computer crafting. What frightens me today is so few young people having the interest or ability to do such work, and the priceless learning and skill they could gain from doing so.

Bruce Gentry, KA2IVY

Is the F-111 Nav computer part of the INS system? Also the Navy boxes might be part of an INS system. I worked at Litton in SLC back in the 70's & worked on the Analog INS as well as the digital. The analog systems had electro-mechanical inetegrators for all 3 axis. I left when I was told I was going to be put on the Astro INS, in retrospect I should have stayed, oh well.

On 2020-11-27 1:37 a.m., Thomas Dodge wrote:

I am not sure if I am doing this the correct way. I have three Tektronix
scopes. I have a Tektronix 533 scope that there is no trace. I have a
Tektronix 7704A, and the intensity is very very bright, and the
Time/Division switch has no effect. I also have a Tektronix 684A that I
bought from a surplus place, and had been on the shelf for a long time.
When I first brought it home and plugged it in, it didn't do anything, so I
turned it off and on again. After a while, it decided to work, and went
through the self test, and it was fine. I turned it off again, and then on
again, and it was still ok. I just turned it on again some months later,
and now it has no display on the screen at all. Usually when it was powered
on, the front panel lights will come on and start to initialize, but it is
not doing that now. Can anyone help with this? This is really a great scope

This might be a redundant suggestion but have the basic power supply
checks been done? Do you have a service manual?

--Toby

and the best one I have. Any help with this is appreciated. I did read
somewhere that it might need a chip replacement, but not sure. Thanks very
much.
Thanks,
Tom Dodge

On Tue, Nov 24, 2020 at 5:58 PM Dave Peterson via groups.io <davidpinsf=
[email protected]> wrote:

What parameters besides capacitance, voltage, and temperature are
appropriate for replacement capacitor selection?

I guess configuration and size, of course. What fits.

This is the typical C1419 for a 465 scope. Just did an online search and
am overwhelmed by the number of varieties.

Are there most reliable, quality, trusted brands? Are there some to be
sure to stay away from? How to choose!?

Thanks,
Dave

Have you read the full description of this guy's scope? "i plugged it in but it started smoking (white smoke) so i turned it off" "i will take the side panel off tomorrow and take some pictures" Those pictures should be a sight to behold!