Direct link to VK2SEB's HP141T on a LCD video...

???

73? Dave G8KBV

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Created on and sent from a Unix like PC running and using free and open source software:

Ulf, that's a pretty tight through-hole board. Will you provide a complete parts list with component part numbers? It will be difficult to assure fit without that.

Larry

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Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

Hi all,
been reading through the posts in hopes I may latch on to some insight as to what might be afflicting my old HP 8648C sig gen. Used very occasionally to test and calibrate amateur radio gear, and unfortunately, after sitting idle for 1+ years seems to have developed a major problem.
While the unit powers up ok and appears to pass its initial self-test (no trouble codes posted), most functions including setting power and amplitude are not working from the front keyboard. The RF on/off button does nothing. Interesting thing is, the frequency and amplitude dials do change the display readings but I'm unable to engage the RF output. Also, when you dial down the output level you normally would hear the attenuator stepper working (clunk), now there is nothing. I do note however that the attenuator stepper does clunk on initial power-up and self-test as per normal, so maybe a bit of good news there.
About the only function that appears to respond on the front panel is the memory store recall buttons.
Unfortunately I'm not too familiar with these units, nor do I have any documentation to work from. This group keeps popping up as the defacto source of information on these older devices. Hoping perhaps someone might have a suggestion as to where to start or may have run into something similar. Hate to scrape her as its been a great piece of kit for many years and has worked without issue.
I'm wondering about a controller board perhaps or even a bad battery (if there is one). But why no errors reported?
Happy to provide more information as required.?
Regards,

Kirb,? VE6IV

A small batch of the new A15 boards finally arrived and I had to populate and test one immediately.
Having upgraded the design with a better voltage reference REF102 and a zero-drift
OP-Amp it seems to work quite OK. Presently testing for noise and drift.

If no problems - I will upload the design files to KO4BB in a near future.

Cheers

Ulf Kylenfall
SM6GXV

The manuals are sold. Thanks for the interest!

The manual is sold. Thanks for the interest!

The manual is sold. Thanks for the interest!

Me, personally, I always enjoy doing lots of extra keystrokes
and effort, to fix something that is not really a problem.

Word Processors often have non breaking spaces, but does your
email editor, or this wiki's web editor, have them? Any idea
how many mouse strokes will be required to insert one?

For me the potential for the wrapping of the unit onto a new
line by some automatic line wrapper, forbids the use of a space
before a unit. A non breaking space is a complication that I am
just not going to indulge.

Standards organizations always seem to have a few contributors
whose sole purpose seems to be to hobble those that do the real
work in the field being standardized. (Anyone remember ANSI C
and trigraphs? Anyone ever use trigraphs?)

Max Planck once opined:
"Science makes progress funeral by funeral: the old are
never converted by the new doctrines, they simply are
replaced by a new generation."

I'm going to do that.

-Chuck Harris


On Sun, 9 Jan 2022 00:05:03 +0100 "Carsten Bormann"
<cabocabo@...> wrote:

On 2022-01-08, at 23:11, Dave McGuire <mcguire@...> wrote:

The big issues come when line wrapping splits the units from their
quantities. I can't stand that.

(The non-breaking space U+00A0 was invented for avoiding such line
breaks. As with ? and ¦¸, that is easier to type on some platforms
than on others. Unfortunately, my mail composer doesn¡¯t seem to like
it at all.)

Gr¨¹?e, Carsten

On Sun, Jan 9, 2022 at 10:35 AM, Bruce wrote:

Says the video does not existent - check the link please !

It plays for me.

On Sun, Jan 9, 2022 at 05:39 AM, Roy Thistle wrote:

I'm very happy to know you've finished the work on the kluge that VK2SEB left hanging 4 years ago.
Great, can you point us/me to the source code, and pcb files.

You're delusional.? I said nothing of the sort, just remembered seeing this "kluge", as you call it, some time ago and thought I'd mention it here.? If you watch the video, you'll see that it does indeed work, after a fashion.? The source code can be found on github:

https://github.com/schnommus/stm32_hp141_lcd

Please let us know when you have the software working to your satisfaction, so the rest of us can judge YOUR work.

I have managed to find links to several pdfs of the 35660a service manual but it appears none of them are complete? Including the one from Keysight? I.e. Section VII Assembly Level ? Section VII Component level, Am I misreading something ? Does anyone have a link to the complete servive manual ?

Much appreciated?

Regards

Richard

¿ªÔÆÌåÓý

From: Richard Merifield
Date: Sun, 09 Jan 2022 03:32:31 PST

Thanks Dave, can this drift with time ? Or does it suggest something else may be beginning to fail? I will adjust and see how it goes.

---

Hi.

Yes, they can drift over the years, being analogue circuitry, especially if there is an adjustment.

I'd do the usual checks to see that all the DC power rails are in spec, then look for any preset adjustment for the sweep gen circuits within the CRT module.?? I suspect that the CRT module may be a bought in item from somewhere outside of HP, so information might be sketchy if exists at all.? It may be similar or common to other instruments too, so some cross referencing of parts lists etc may help if a replacement is needed from some other donor unit.

Obviously a service manual with schematics for the 35660A would be useful to have too.? There seem to be several options to obtain one from the web, but how clear and complete they are, I do not know.? Artek Manuals don't appear to list it sadly.

Take care.

??? Dave G8KBV

-- 
Created on and sent from a Unix like PC running and using free and open source software:

Yeah, it would be helpful to compare the EEPROM image from two units.
Though I was thinking more about the actual firmware that runs on the
mainframe, I could reverse engineer that and figure it out.

I do have a firmware image from my 83480A (aka 54750A) which I expect
to be very similar and I've worked out the EEPROM format/checksums
that it uses:

The first two bytes are a (big-endian) uint16 denoting the total
length of the data.
The first checksum is verified by summing the first 0x7A bytes and
checking that the result is zero, and the checksum byte itself is at
0x48
The second checksum is verified by summing bytes over the whole image
(using the length field), and that checksum byte is at 0x7A.
Both of these schemes validate correctly on the 54712A image posted above.

Another thing to note is that the byte at 0x07 is a sort-of model ID
and it needs to match what the firmware expects for the model string
just after. Without a 54720 firmware image I can't tell what it's
supposed to be, though it could be guessed in maybe 10-20 tries if
someone's keen to do a bit of tedious work? :)

Cheers,
Mike

On Wed, 5 Jan 2022 at 15:44, Arkadiusz Gibes via groups.io
<arkadiusz.gibes@...> wrote:

I was thinking about exactly the same. Do you want to compare to see where the check sume is stored ?

W ?roda, 5 stycznia 2022, 03:26:37 UTC, Mike Walters <mike@...> napisa?(-a):


Does anyone have a copy of the 54720 or 54710 firmware disk? If I
could take a look at that, I can probably figure out how to make a
54717a eeprom image for you.

On Tue, 4 Jan 2022 at 16:55, Arkadiusz Gibes via groups.io
<arkadiusz.gibes@...> wrote:

I already found the 54712 eeprom image that you shared. Do you have any possibility, to download same firmware from the other unit ? I would like to compare. I have one 54712 unit, but still don't have programmer.

W wtorek, 4 stycznia 2022, 16:46:54 UTC, Ovidiu Popa [Business] <ovidiu.popa@...> napisa?(-a):


Sorry, no, I gave up and wrote off the 54720D. I have too many scopes anyway, from 100MHz to 50GHz, not enough incentive to spend more time on this. Meantime, watching for a 54717A, ideally someone owning one could dump the EEPROM. I know if I'd get one, this would be the first thing I'd do, this HP money grabbing calibration abomination has to end.

If someone wants to pick up, I can forward the 54712A EEPROM binary.

This started me thinking about the availability of a CRT for the 141T.? I am surprised to see that the availability of them seems to have dried up on that popular auction site and elsewhere.

?

Several years ago it seemed like there was no end to the sources for the NIB CRTs part numbered 5083-2511.? They were selling in quantity lots for $50 each when HP was still willing to sell them to you for around $1400 each.? I¡¯m assuming that the military must have divested themselves of their parts stock of this item.

?

At that time I picked one cheaply priced NIB CRT up as a spare (have two 141T display sections in use with RF & IF plug-ins on the benches).? I wonder if anyone has a quantity of these tucked away somewhere from that large lot sale than happened then.

?

From what I can gather it appears that there were at least four different part numbered storage tubes used over time in this unit most likely due to tube design changes that didn't affect the supporting display section circuitry (assumption here).? The ones I found are:

?

5083-2511

5083-2572

5083-2587

5083-9095

?

The change from -2587 to -9095 appears to apply to units serial numbered 1147A and up although I have seen it appear occasionally in units with earlier serial numbers. ?This data was only obtained from the military technical manual TM 11-6625-2781-14&P.

?

Does anyone have additional information to add on these series of tubes?

?

Greg

The link works for me¡­..

-Dale

Says the video does not existent - check the link please !


Quoting Jim Allyn - N7JA <jim@...>:

On Sat, Jan 8, 2022 at 05:05 PM, Carsten Bormann wrote:

(The non-breaking space U+00A0 was invented for avoiding such line breaks.
As with ? and ¦¸, that is easier to type on some platforms than on others.
Unfortunately, my mail composer doesn¡¯t seem to like it at all.)

Okay, I learned something here. What a beautiful solution!

Confirm receipt on Cosmo Communicator with AirMail

I wonder what will be the oddest hardware from which we get a report

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Sent from my Gemini PDA with the Airmail? app. Please excuse my verboseness - I have a great keyboard and just cannot resist. Get a Gemini PDA from Planet and type on the move! www.planetcom.co.uk

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¿ªÔÆÌåÓý

- - - - -
With best regards
Tam HANNA 

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