8560E New to Me: Some Issues & Questions

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While I have an extensive background in computers, communications and electronics in general, I have just recently gotten back to hands-on troubleshooting and repair after 50+ years on the business side of technology. I wanted to know more about spectrum analyzers so decided to purchase a project instrument as a learning tool. Some months ago I found a listing for an Agilent 8560E on one of the amateur radio sale/swap forums; the seller described it as “working” and in good condition, so I made an offer he could easily refuse, but he didn’t! ?I wound up with s/n 39434A04625 and it was much as represented. The physical condition is excellent, and except for one small blemish on the case, it might pass for new. When I originally received the instrument several months ago, I powered it up to see if it could get through the onboard diagnostics; it passed all of these tests and went on the shelf until I could devote more time to the project. It’s now back on the bench and I am starting to dig in. For a first quick & dirty evaluation, I compared the results on the 8560E to two other spectrum analyzers using a calibrated signal generator over the range of 100 KHz to 520 MHz (top end for my signal gen), and the results across all three SAs were virtually identical. In this process I noticed two issues that I’d like to learn more about:

1.?????? The alphanumeric information on the screen is irregular in appearance. It is readable in every case, but the brightness varies within each character. The signal trace and graticule traces do not have this problem. I looked through the service manual and it mentions something like this but the troubleshooting tips seem vague and limited in scope.

2.?????? In looking at the elapsed time readout via the Recall function, I am seeing what appears to be 60432 hours. Or is it 6043.2 hours, with the decimal point missing? Seems unlikely to me that it could be the higher number, but perhaps so. Neither the User or Service manual seem to give definitive info on the format of this number.

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Any constructive guidance on these issues much appreciated. Given the nice overall condition of this instrument, I am somewhat inclined to invest some dollars to deal with known issues which arise with these instruments over time. Any pointers to a guru who would be willing to take this on also appreciated.

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RB

The hours indication in Recall is in hours, not tenths.?? Sounds like a lot of time, but if it works as you describe, I would not be concerned.

I have an 8560E with ~15000 hours and it has worked perfectly for the 3 years I have owned it.

The biggest problem with this series of scope is cathode poisoning on the CRT. First symptom is the text gets soft

My recommendation is to get a replacement LCD display from Simcomm labs aka newscope kits are about $650 and take about 4H to install you also reduce weight by about 10 pounds. I They also sell through the well known auction site.

Since so many adjustments are dependent on X CRT divisions either in the X or Y dimensions a solid display system is a must. Also the LCD display adds value to the instrument as it makes it equivalent to a EC series of the same scope with the same multicolor display.

My recommendation is to get a replacement LCD display from Simcomm labs

Have been looking at this. Just need the courage! ?

开云体育

Go for it !

Well … I spent some time this AM reading through the Newscope 6 (8560E kit) manual and found good news and bad news there. The good news is that the end result is quite nice. The bad news is that the install, with my limited recent experience in such matters, seems in the same league as a heart transplant! It’s the kind of thing where you’d much prefer the person doing the conversion had done it at least a few times previously. So far, I have never seen an 8560E with the case off. Just getting the anatomy understood will be a challenge. I’d much rather commission an 8560 expert who has done this before to install this mod, preemptively replace components which commonly fail, and do a calibration, etc. Short of this, I may wait for a serious failure that leaves no choice but to open it up and jump in. In the meantime, I will keep looking at the photos of the end result for motivation.

OTTH, I recently tore into a Tek 495P SA (also had never previously had the case off) which had problems and found and fixed the problem without much difficulty. This was relatively easy however: sourcing a replacement memory board on eBay, recapping, and programming the firmware EPROMs. Maybe I can do this!

Thanks Shaun, for the link. This may tip me over to go ahead.

RB

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On Sun, Nov 4, 2018 at 09:31 AM, tmillermdems wrote:

where are you located?

Boston metro area

I have done some limited additional troubleshooting (mainly by observing more carefully what I am seeing on the screen.) Here is what I have found:

1.?????? Only the alphanumeric characters seem to have a problem of non-uniform intensity of the strokes which form each character, and this seems most apparent on the curved portions of characters like “0”, “5”, “P”, etc.? Characters formed by straight line segments do not exhibit the intensity variation.

2.?????? The graticule lines and signal traces are sharp and clear with no apparent intensity variation or distortion.

3.?????? The alphanumeric characters become no longer visible as the intensity is reduced from maximum (255) toward zero at a still relatively high intensity levels (say, 100), while the graticule lines and signal traces remain visible, sharp, and undistorted until the intensity setting nears zero.

4.?????? When the “SCREEN TITLE” function is turned on, a complete list of characters appears on the screen to allow a title to be composed. The character currently selected appears at a higher intensity than the other characters. As the controls are used to step through the characters, each character is intensified in turn. A the intensified level of brightness, the non-uniform intensity described above is not seen. IOW, all characters are uniformly bright.

5.?????? The “CRT ADJ PATTERN” brought up via the “CAL” button appears as shown in the service manual, except that the numbers in the center box exhibit the non-uniform intensity described above.

6.?????? The symptoms described are seen everywhere a character appears on the screen and are not related to any specific screen position.

7.?????? I have no idea when this instrument was last adjusted or cal’d. No stickers of any kind on the exterior.

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So … what does this all mean? A SWAG on my part, but it looks to me like something is out of adjustment with the Z axis signal from the character generator. (Not yet sure just how this works.) It wouldn’t seem to be a CRT problem as it is limited to just the text characters. Any insights from the pros here?

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At 2018-11-05 12:07 PM, Rick Boswell wrote:

So … what does this all mean? A SWAG on my part, but it looks to me like something is out of adjustment with the Z axis signal from the character generator. (Not yet sure just how this works.) It wouldn’t seem to be a CRT problem as it is limited to just the text characters. Any insights from the pros here?

I'm not familiar with this particular unit, but have a basic familiarity with the hardware needed to generate vector characters. I'd be looking for a bad cap where the slew rate of the X and Y axes are controlled, probably two identical caps with similar failures. If the slew rate isn't controlled, the beam jumps from endpoint to endpoint, "painting" very little light in the middle. Hmmm....I can see counterarguments against my analysis too. Are there differences in brightness of horizontal vs. vertical strokes? I'd be quite curious what you find.

Steve Hendrix

On Mon, Nov 5, 2018 at 09:42 AM, tmillermdems wrote:

Have you done the 7 pages of adjustments for the display calibration?

Not yet. Have not yet removed the case - trying to think through the possibilities before I start changing things. I have the manual, but I don't have the arsenal of test gear recommended in the manual and am probably not going to have this gear in the foreseeable future. I may resort to winging it a bit.

Are there differences in brightness of horizontal vs. vertical strokes? I'd be quite curious what you find.

No - straight lines, whether vertical, horizontal or diagonal are uniformly bright.

RB

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开云体育

It IS a CRT problem, ?the first signs of cathode poisoning are the text characters going soft. ? The characters are drawn as vectors not as a bitmap and a raster scan. ? Hence the distortion seen on the screen as the electron gun can longer generate a tight beam of electrons.

Regarding the Newscope upgrades, they now seem to only sell the VGA
LCD display. 640x480 seems to me a bit coarse for replacing a 1024x1024
vector display.

Has anyone tried it? Is it an upgrade, or a downgrade from a working
original CRT?

What about things like speed, brightness, ???

-Chuck Harris

Scott McGrath wrote:

On Mon, Nov 5, 2018 at 01:54 PM, Scott McGrath wrote:

It IS a CRT problem, ?the first signs of cathode poisoning are the text characters going soft.

Scott,

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Thanks for your response, and especially the link to “CRT Restoration for the Brave”. While the appearance of my CRT is decidedly different from any of the photos at this link, as you suggest, cathode poisoning may well be the culprit. I have already made the mental commitment to go to the SimmConn/New Scope LCD kit but since my 8560E was acquired as a learning aid, I’d like to see what I can learn from some additional troubleshooting. My plan of attack:

1.?????? Remove the instrument from the case and identify what is what, including the location of the controls associated with the Display Adjustment procedure in the SM.

2.?????? Carefully attempt to perform the DA procedure. (I say “carefully” as this is entirely new ground for me).

3.?????? Depending on the results of step 2 above, consider attempting the restoration procedure outlined in the link.

4.?????? Install the SimmConn/New Scope kit once my confidence level is sufficiently high. (I emphasize “confidence” as I have looked at several of the SimmConn kits and the one for the 8560E is more complex than some of the others. It requires installing five DIP sockets on top of existing soldered-in DIP ICs and soldering these to the IC pins. Not brain surgery but technique sensitive for sure. (In a much earlier life I had a job as an electronics tech at Gould/Brush Instruments troubleshooting and repairing strip chart recorders on the production line. They insisted on mil quality soldering, so I can hopefully call up those skills one more time. However, IC’s were still some years off at that time.)

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If I screw this up I can likely sell the SA as a “parts” unit for more than I paid for it given what I am seeing on eBay. Progress reports to follow … slowly!

RB

Regarding the Newscope upgrades, they now seem to only sell the VGA
LCD display. 640x480 seems to me a bit coarse for replacing a 1024x1024
vector display.

Has anyone tried it? Is it an upgrade, or a downgrade from a working
original CRT?

What about things like speed, brightness, ???

640x480 is the correct resolution for an 856xA/E portable model. That's what was used in the later 8560EC series. However, it's best to use a 1024x768 XGA panel to replace the CRT in an 85662A-based benchtop model (8566/8567/8568). The latter have 1001 points of display resolution while the portables only have 601.

For some reason SimmConn's page for the 85662A display says that XGA resolution requires a special order. I guess there's some sticker shock involved, because I can't think of any other reason not to go with XGA when upgrading the big-iron hardware.

-- john, KE5FX