Re: HP Agilent 8753ES VNA repair [Help]
Sorry, test point TP12, TP10 and TP11 are ground from sampler…no signal on that. Input signals are on TP16, Tp18 and TP20. Output R, A and B are -6dB lower than input (TP 9,8 and 7). ? Signal at TP16 R: 1.18Vpp Signal at TP18 A: 3.75Vpp (no loop cable) Signal at TP20 B: 3.51Vpp (with loop cable) ? PRESET SWEEP SETUP CW FREQ (defaut 1GHz) SWEEP TIME 10sec ? 
? ? ? ? If the three signals are absent, there would have to be a common point between them, so there is the local power supply. ? Signal A, B and R on DIGITAL IF come from of the 3 outputs of samplers at 4kHz via motherboard. Check TP12, TP10 and TP11 connected to input lines from mother board. ? If there are no signal at theses points, problem is near samplers? ? ? 
|
Manual for HP 466A amplifier
If anyone has a copy of the manual for this old amplifier I'd appreciate a copy.? Even just the schematic diagram would be appreciated.? I have had this amplifier for years and use it once in a while.? ?There's a DC offset on the output now but appears to have low distortion.? ? Ran on mercury batteries. Now the battery contacts are all corroded so I just connect a power supply to the test sockets.? ?Has germanium transistors and I think it is '60's vintage.? 10 Hz to 1 MHz is its frequency range and has 20 dB and 40 dB selectable gains.
I did check the files.??
Thanks!
Pete??
|
Re: Service manual scan post processing
I should have said: [...] scan 600dpi, ==greyscale== .tiff-s !!ONLY!! I don't want to have to dig for that so give me a link, I'll post
process and get back to you.
I have long since and flat out mastered document scanning and
restoration, I've done 1,000s upon 1,000s of pages and brought documents
back from nothing to virtually as printed appearance.
You need Acrobat 9.xx, Photoshop 7.01 with some well configured
filters, scan 600dpi .tiff-s !!ONLY!! , use Acrobat to assemble the
Photoshopped.tiff-s then Clearscan OCR. Don't worry about the .tiff file
sizes, ClearScan will reduce the size about 10-fold.
I use an Epson V600 that talks USB2 and the companion Epson software
and a Canon DR-4010C that talks USB2 and SCSI, which I use, and it's
companion driver and software. It'll duplex 24-bit color @ 600 dpi at
about one second per face.
I would be interested in feedback from members as to how well their post
processing for .pdf works with these files.
Especially interested in ways of preserving the picture quality whilst
also tidying up / compressing the pages of text
Peter Bill @ PEARL, Inc.
|
Re: Service manual scan post processing
I don't want to have to dig for that so give me a link, I'll post process and get back to you. I have long since and flat out mastered document scanning and restoration, I've done 1,000s upon 1,000s of pages and brought documents back from nothing to virtually as printed appearance. You need Acrobat 9.xx, Photoshop 7.01 with some well configured filters, scan 600dpi .tiff-s !!ONLY!! , use Acrobat to assemble the Photoshopped.tiff-s then Clearscan OCR. Don't worry about the .tiff file sizes, ClearScan will reduce the size about 10-fold. I use an Epson V600 that talks USB2 and the companion Epson software and a Canon DR-4010C that talks USB2 and SCSI, which I use, and it's companion driver and software. It'll duplex 24-bit color @ 600 dpi at about one second per face. I would be interested in feedback from members as to how well their post processing for .pdf works with these files.
Especially interested in ways of preserving the picture quality whilst also tidying up / compressing the pages of text
Peter Bill @ PEARL, Inc.
|
Re: HP 54512B (pair) repair
On Thursday 27 February 2025 04:09:31 pm Radu Bogdan Dicher via groups.io wrote: One other unfortunate effect of the spot-welding of the top tab is that the
battery code is not visible. I can probably destroy the battery once out,
and read the CRxyzt battery code, but would anyone have good info offhand
on it? You might find bits of this useful: Scroll down to where they discuss coin and button cells: "IEC designation numbers indicate the physical dimensions of the cylindrical cell. Cells less than one centimeter in height are assigned four-digit numbers, where the first two digits are the diameter in millimeters, while the last two digits are the height in tenths of millimeters. Taller cells are assigned five-digit numbers, where the first two digits are the diameter in millimeters, followed by the last three digits indicating the height in tenths of millimeters." So the size of the battery will give you the info that you need. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
|
Re: HP 54512B (pair) repair
On Thursday 27 February 2025 03:47:52 pm Radu Bogdan Dicher via groups.io wrote: If I understand this right, the correct procedure is to desolder both
tabs?... Given the top tab is spot welded, it may not be reusable? So,
replacing this with the appropriate coin battery socket and a new battery
is the way to go? No, the "tabs" are not re-usable. They're a part of the battery. I've replaced these in a variety of equipment, unsoldering them and then installing a socket and new battery as you describe. The tricky detail is finding a socket with the right spacing to go into the same holes... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
|
Re: HP Agilent 8753ES VNA repair [Help]
If the three signals are absent, there would have to be a common point between them, so there is the local power supply. ? Signal A, B and R on DIGITAL IF come from of the 3 outputs of samplers at 4kHz via motherboard. Check TP12, TP10 and TP11 connected to input lines from mother board. ? If there are no signal at theses points, problem is near samplers? ? ? 
|
Re: Service manual scan post processing
On 2/28/25 17:50, Tom Gardner via groups.io wrote: Reducing the pictures, e.g. *19.tif, to a two level bitmap is unlikely to be successful. To reduce the size, I would try reducing the XY resolution to largely remove the "grain effect", then convert to a .jpg format. Using JPEG for those will result in nasty artifacting around the text, border box, etc. I'd not recommend that at all. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: HP Agilent 8753ES VNA repair [Help]
Yves,
Thank you for your analyse.
I have exactly the same board as you for A10.
?
The ADC test pass with no problem.?
I was not able to get any signal with the scope on TP R, A or B. Quite strange!?
?
?
?
|
Re: Service manual scan post processing
On Friday, 28 February 2025, Peter Brown via <peter= [email protected]> wrote: > So I guess that the native resolution is 300 x 300 dpi and there must be some sort of interpolation for the 600 x 600 scans > ? > I will rescan a couple of representative pages at 300 x 300 dpi, 256 level gray scale? for members to take a look at. > Hopefully this will close out the topic of finding the best resolution / bit depth / post processing to use when getting scans from the archive to people To some extent it is possible to trade XY resolution with depth resolution, and vice versa. Just make clear what has been used. For a paper source 300dpi is more than enough. Your scans seem reasonable enough, hence my surprise that holes in letters had disappeared. Reducing the pictures, e.g. *19.tif, to a two level bitmap is unlikely to be successful. To reduce the size, I would try reducing the XY resolution to largely remove the "grain effect", then convert to a .jpg format.
|
Re: HP Agilent 8753ES VNA repair [Help]
This is version of board DIGITAL IF of my 8753ES. ?
|
Re: HP Agilent 8753ES VNA repair [Help]
Hi, ? To make a short summary: You have tested several RF paths, <300kHz, <16 MHz, CW 1GHz, sweep up to 6GHz. In all cases the signal is noisy for all S parameters, but always PHASE LOCKED. You have done tests on samplers A, B and R. Even if B seems weak according to the measurement you have done, this would not affect the other possibilities. The only common point between all these paths is the DIGITAL IF. ? Do the oscilloscope tests for channels R, A and B on the DIGITAL IF. Here again there are separate paths for these three signals, but they have common power supplies and a switch leading to the ADC. ? Out of curiosity do TEST 17 ADC LIN. This test activates a precision ramp at low frequency and tests the ADC. ? Here is a picture of a DIGITAL IF PCB, does your PCB look like this version. If so, you have the schematics available for that, here is the DIGITAL IF section. ? ---------------- CW mode 1GHz, test on DIGITAL board. ? 
? 
? ----------------------------- ? 1 GHz, 0 dBm, SPAN 0 mode, PORT 1 output:??? your signal is OK, with same setup, similar result (I have 1D5 option, high stability ref). ? 
? R output power verification at 1GHZ, SPAN 0 mode :? nominal -16dBm, it’s OK ? ------------------ ? ?
|
Re: Service manual scan post processing
On 2/28/25 17:11, Dave_G0WBX via groups.io wrote: I've had a play with GIMP on Linux, and I can (to my eye anyway) sharpen things up quite nicely.
But, as yet, I've not hit a file with a schematic!.
Can you tell us which file(s) have schematic diagrams, as their needs are often different to processing text. I didn't bother with any sharpening; the original scans really aren't too bad. One example of a page in that document that has a schematic is page 20. I did a quick pass in GIMP on each TIFF file, to determine the most reasonable approach on a per-page basis. Then I threw together a quick script that used ImageMagick to apply those functions per file, concatenate them to a PDF, then do the OCR pass. Some of those pages would benefit from some manual editing, like cropping, etc, but they're perfectly readable as they are, at least to me, and having the text layer underneath the page image is good. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: Service manual scan post processing
I've had a play with GIMP on Linux, and I can (to my eye anyway)
sharpen things up quite nicely.
But, as yet, I've not hit a file with a schematic!.
Can you tell us which file(s) have schematic diagrams, as their
needs are often different to processing text.
Regards.
Dave 'KBV.
|
Re: Service manual scan post processing
On 2/28/25 16:18, Peter Brown wrote: Looking at the service manual for the Canon MS-8000 reveals the following
Photosensitive element
1) Type: CMOS CIS (image sensor
2) Density of element: 300 dpi
3) Effective elements: 3488 (effective reading length 295.3mm)? (this calculates out at 300dpi)
Output resolution
1} Standard: 300 x 300 dpi
2) Fine: 600 x 600 dpi
3) High speed: 200 x 200 dpi
So I guess that the native resolution is 300 x 300 dpi and there must be some sort of interpolation for the 600 x 600 scans
I will rescan a couple of representative pages at 300 x 300 dpi, 256 level gray scale? for members to take a look at.
Hopefully this will close out the topic of finding the best resolution / bit depth / post processing to use when getting scans from the archive to people I sure would like to get my hands on one of those scanners. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: Service manual scan post processing
On 2/28/25 10:00, Peter Brown wrote: Any other takers for trying to post process the 256 level .tiff files? -? found at
files - temporary directory for photographs and help relating to emails and posting/11707A Service PFX 1525A 11707-90007 SEP 1977 rev 1
The files contain pages of just text, pages with text and images, and pages with circuit diagrams
I'll leave them up for another couple of days and then remove as they are pretty big I took a whack at it and didn't get anywhere near as much of a size reduction as you did. But, the file looks great, passes a PDF/A validator, and has been OCRed. And, no embedded ads. ;) I've put it in the directory with the TIFF files. I applied a binary threshold to all of the text pages, and posterized the pages with graphical content at varying levels, mostly 24 and 32, to preserve the image quality. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: HP Agilent 8753ES VNA repair [Help]
I just mesure Sampler A6/B in S22 (instead of S11) and the level is correct at 1MHz with about -8 dBm.?
I am quite confuse about the measurement at?
37 MHz.
?
|
Re: HP 54512B (pair) repair
Hi Radu,
I was only making an assumption that it is the BR/CR2430. Can you use a
caliper to measure the diameter at least to see if it is in the 24mm
range? For the height is not so important since you have enough space
and it will fit in the holder.
I just came from work, I wanted to reply much earlier to get the BR
version instead of the CR one.
I attached a PDF with the differences between the BR and CR chemistries
and usage types.
All HP/Agilent equipment that I replaced batteries in had a BR model inside.
Regards,
Razvan
toggle quoted message
Show quoted text
On 28/02/2025 21:46, Radu Bogdan Dicher via groups.io wrote: Harvey and all,
I guess you're right, once the unit is unplugged there shouldn't be a
path to short the battery and lose the existing memory (though I haven't
done this, so I'm not aware of all the practical implications).
I currently have an order for some CR2430 batteries - went with Razvan's
call on that one (and Razvan, no worries, I can return them if not the
correct part) - and PCB mount holders for them. Sure, the more common
CR2032 would probably work just fine, but I always prefer to repair
something as close as I can to its original configuration. I'm not sure
how likely it is that a random 2430 holder will fit on the PCB, but if
worst comes to worst, I can either return both, or work out something
with a bit of wire.
I'll seek to measure the existing battery once I have the board out and
therefore access and before removing the current battery, but my working
hypothesis is they're depleted.
Radu.
On Fri, Feb 28, 2025 at 12:17?PM Harvey White via groups.io <
groups.io> <madyn@...
<mailto:[email protected]>> wrote:
Correct.? What is likely being done is to replace the battery while the
equipment is line powered.
If the battery is dead, then obviously, no problem.
What a safer approach (to me) would be is to supply a backup voltage to
the circuit, device unplugged, then cut the battery loose.? Then
desolder and replace, then remove the supply.
I'm not sure that interrupting the ground is wise.? If you do go
with an
isolation transformer, then that one meg resistor from the iron ground
to chassis ground is a good idea.
I wonder if there's a battery holder that would be soldered into the
board with the same spacing?
Harvey
On 2/28/2025 11:15 AM, Radu Bogdan Dicher via groups.io <
groups.io> wrote:
> Harvey - correct me if I'm wrong, but I think the issue is supplying
> the 3V while working on the battery (soldering with a grounded iron)
> from an external power supply so the memory would be preserved.
> What I'd probably do is run the soldering?station off of an isolated
> power supply (mine is a BK 1655) with an interrupted ground. I'm not
> entirely sure on ESD protection, but if I'd do this while supplying
> the 3V off of an external power supply, that'd probably do OK
handling
> that part.
> Radu.
>
> On Fri, Feb 28, 2025 at 7:33?AM Harvey White via groups.io
<>
> < <>>
<madyn@...
<mailto:[email protected]>> wrote:
>
>? ? ?You could, of course, simply unplug the meter you're working on,
>? ? ?so it's
>? ? ?isolated?
>
>? ? ?Rubber mat if needed.
>
>? ? ?Harvey
>
>
>? ? ?On 2/28/2025 4:16 AM, Leo Kroonenburg via groups.io <
groups.io>
>? ? ?< <>> wrote:
>? ? ?> I modified my soldering station lije this:
>? ? ?> Instead using the hard ground wire to the tip I replaced it
with
>? ? ?a 1
>? ? ?> MOhm resistor inside the soldering station.
>? ? ?> No more risk of shorting stuff, and still a 0V potential in
the tip.
>? ? ?> Works for me.
>? ? ?> Leo
>? ? ?>
>
>
>
>
>
>
>
|
Re: Service manual scan post processing
Looking at the service manual for the Canon MS-8000 reveals the following
?
Photosensitive element?
1) Type: CMOS CIS (image sensor
2) Density of element: 300 dpi
3) Effective elements: 3488 (effective reading length 295.3mm)? (this calculates out at 300dpi)
?
Output resolution
1} Standard: 300 x 300 dpi
2) Fine: 600 x 600 dpi
3) High speed: 200 x 200 dpi
?
So I guess that the native resolution is 300 x 300 dpi and there must be some sort of interpolation for the 600 x 600 scans
?
I will rescan a couple of representative pages at 300 x 300 dpi, 256 level gray scale? for members to take a look at.
Hopefully this will close out the topic of finding the best resolution / bit depth / post processing to use when getting scans from the archive to people
?
|
Re: HP 54512B (pair) repair
Don, Thank you for this, as just posted I sourced 2430s and holders and am hopeful that will work OK. I appreciate the link!? Radu.?
On Thu, Feb 27, 2025 at 4:08?PM Don Bitters via <donbitters= [email protected]> wrote: Radu, I have no personal knowledge of the this battery replacement, however my best guess would be a CR2032, or CR2025 type. The coin/button cells of this type seem to be 3V lithium. If you cannot lift the outer tang assembly vs. the inner recessed oval then it is one piece and tack welded to the battery “-“ terminal. The other side of the battery that you cannot see is held to the spring contact on the board by the spring tension of the neg assembly tang.? You can peel the negative tang off the battery, but that generally eliminates the spring tension of the negative terminal.? You would have to recreate that tension and install a new battery.? This vendor has quite a few button batteries of all sizes and several with pre-mounted tangs that have been tack welded on.
| |
Liam Perkins
Dave McGuire
MattSNE
