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

--
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

--

¿ªÔÆÌåÓý

- - - - -
With best regards
Tam HANNA 

Enjoy electronics? Join 13500 followers by visiting the Crazy Electronics Lab at 

¿ªÔÆÌåÓý

Confirm visibility of all symbols on Thunderbird, running on Ubuntu 20.04LTS

- - - - -
With best regards
Tam HANNA 

Enjoy electronics? Join 13500 followers by visiting the Crazy Electronics Lab at 

On Sat, Jan 8, 2022 at 08:30 AM, WB4IUY wrote:

I have a 141T mainframe

WB4IUY... not that it matters maybe... but I'm assuming its a 141T frame with SA plugins?
Do you have a variable persistence CRT?

Hi N7JA
Fantastic!
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.
Best regards.

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.

¿ªÔÆÌåÓý

HP35660a DSA screen rolling issue
From: Richard Merifield
Date: Sun, 09 Jan 2022 02:07:37 PST

Hi all

I have just noticed an issue when I turn on my 35660a dynamic signal analyzer. The crt screen image rolls from top to bottom (I.e. like the old tv horizontal tune/sync), initially fast then begins to slow down. Sometimes the rolling stops but other times I need to switch the unit on and off to get a steady image. Any thoughts on what could be the issue ? I have been meaning to open the unit up since I purchased it to replace any suspect capacitors etc, it¡¯s been working fine up until now.

regards

Richard

---

Vertical Sync/hold adjustment in the CRT monitor assembly, assuming the V sync signal is present...

73

Dave G8KBV

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

¿ªÔÆÌåÓý

I find the ALT+nnnn method convenient to enter several symbols I frequently use:

¡ã ¦Ð ¡À ¡Þ ? ¦¸ € as well as some Spanish and German characters. There are keystrokes available for *many* special characters this way. I keep a table handy...

It will be interesting to see if the special characters I entered above appear in everyone's email reader. I typed: degree, pi, plus/minus, infinity, micro, Omega and Euro symbols above.

---

Seems to have propagated OK here.

T'bird 78.14.0 (64-bit) on Linux Mint/Cinnamon.

As well as my ancient phone with Android 5.1 and the Gmail client/app.

73

Dave G8KBV

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

Hi all

I have just noticed an issue when I turn on my 35660a dynamic signal analyzer. The crt screen image rolls from top to bottom (I.e. like the old tv horizontal tune/sync), initially fast then begins to slow down. Sometimes the rolling stops but other times I need to switch the unit on and off to get a steady image. Any thoughts on what could be the issue ? I have been meaning to open the unit up since I purchased it to replace any suspect capacitors etc, it¡¯s been working fine up until now.

regards

Richard

If the CRT goes out, you could always replace it with an LCD:

https://www.youtube.com/watch?v=CwwRvqHGyts

Dave McGuire wrote:

On 1/8/22 6:05 PM, Carsten Bormann 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.)

? Well, I'm an ASCII man here.? Just like leaded solder, I figure I can stay in that world until I'm dead.

????????? -Dave

I like the attitude :-) .? After all, we adapted pretty fast to early personal electronic communications' limits on technical issues under all-caps platforms.? What does the string "100 MFD" or "100 UF" mean?? And regarding solder: I don't like unleaded solder. However, I would like to have the experience of silver-soldering: some instruments from the mid-20th century look just darn beautiful with silver solder.

In non-english conversations, waters are even more troubled. Language-regulating institutions do exist, and some of them insist on using local language translations for the names of standard units in the SI system, in clear violation? of SI rules.? I quarrel all time? about this with my colleagues in Colombia.

carlos.

On Sat, Jan 8, 2022 at 10:00 PM, Larry McDavid wrote:

¡ã ¦Ð ¡À ¡Þ ? ¦¸ €

All arrived safely from my Yahoo+ account on my iPad Pro

Larry
AC9OX

On 1/8/22 6:05 PM, Carsten Bormann 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.)

Well, I'm an ASCII man here. Just like leaded solder, I figure I can stay in that world until I'm dead.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Re: use or non-use of a "space" character following a numeric value and preceding the unit-of-measure symbol. For example, per ISO: 1750 ¡ãC.

I am familiar with using a non-breaking space in Microsoft Word but I had not tried it in my Thunderbird email client. I just did that and it seems to work ok when entered from my laptop keyboard using the Fn keyboard entry for its numeric keypad simulator and ALT+0160. For this entry method to work, the numeric keypad must be used, or its simulator available on many laptop keyboards.

I routinely enter several special characters this way. My desktop computer keyboard has a numeric keypad but my laptop keyboard does not, although it allows entry of numeric keypad number characters by holding down the Fn key and striking various letter keys.

I find the ALT+nnnn method convenient to enter several symbols I frequently use:

¡ã ¦Ð ¡À ¡Þ ? ¦¸ € as well as some Spanish and German characters. There are keystrokes available for *many* special characters this way. I keep a table handy...

It will be interesting to see if the special characters I entered above appear in everyone's email reader. I typed: degree, pi, plus/minus, infinity, micro, Omega and Euro symbols above.

Many folks seem unaware of this simply way of directly entering special symbols from a keyboard. A Google search will find many references and tables available.

I frequently have to enter symbol characters for both temperature degrees and angular or coordinate degrees; if you want to follow the ISO standard, you have to *think* before entry...

If you are writing for publication, there is usually a style manual imposed or referenced and a particular publication may or may not be in accordance with ISO. In such case, the Golden Rule applies: he who has the gold makes the rule...

Larry

--
Best wishes,

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