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HP8560E SA Display oddness

 

Hello group -
I have an 8560E 2.9GHz SA, and it works, except the display characters are not so good.
I tried to take a pic but apparently the shutter speed and the trace times conspire to either make it look worse or better than it really is. So that won't do.
What I see is on text, some parts of a character are very faint while other parts are normally bright. So the number "2" for example, the top and bottom parts might look nice and bright, but the slanty part from top-right to bottom-left is very faint.
I don't see any display settings on the front controls, so I am not able to "wiggle" anything.
Also, the same characters (all of the "2"s, all of the "H"s, etc, look the same as each other. So it isn't an issue with the screen per-se, but with the character generation.
Some letters look normal, M, K, A, maybe a couple of others. Most have an issue.?
The actual RF trace seems to be perfect and bright. So something to do with characters only.
Any ideas for what might be the issue here?
Thanks
Dan
 

Dan,
Just to be clear, did you try the "DISPLAY" button and then adjust the Intensity setting?
--John Gord


On Thu, Aug 11, 2022 at 02:13 PM, dan.meeks222@... wrote:
Hello group -
I have an 8560E 2.9GHz SA, and it works, except the display characters are not so good.
I tried to take a pic but apparently the shutter speed and the trace times conspire to either make it look worse or better than it really is. So that won't do.
What I see is on text, some parts of a character are very faint while other parts are normally bright. So the number "2" for example, the top and bottom parts might look nice and bright, but the slanty part from top-right to bottom-left is very faint.
I don't see any display settings on the front controls, so I am not able to "wiggle" anything.
Also, the same characters (all of the "2"s, all of the "H"s, etc, look the same as each other. So it isn't an issue with the screen per-se, but with the character generation.
Some letters look normal, M, K, A, maybe a couple of others. Most have an issue.?
The actual RF trace seems to be perfect and bright. So something to do with characters only.
Any ideas for what might be the issue here?
Thanks
Dan
 

Yep, sorry i did find the intensity adjustment. Works, but doesn't affect the weirdness.
I found some troubleshooting around the character generation but don't see schematics online.?
I'll check with Artek -
 

Hello Dan,
My recently bought 8560E has the same issue. Intensity is at maximum (255). Graticule is a bit dim too. At first I thought it might be the many Elapsed Hours (8869), but I cannot see burning-in effects. I did shift the image up and down, but no effect. So that looks good. I will try to get inside and find the monitor brightnes/bias pot. Must be there I think. I do have the service manual with CLIP from Artek but I still have to have a look at it.
Did you already investigate further?

Jaap PA0JRK
Netherlands
 

¿ªÔÆÌåÓý

Presumably the power supplies have been confirmed good prior to anything else being done.

Nigel

by banging a nail into a piece of wood...

On 16 Aug 2022, at 18:38, Jaap Rusticus <jrusticus@...> wrote:

Hello Dan,
My recently bought 8560E has the same issue. Intensity is at maximum (255). Graticule is a bit dim too. At first I thought it might be the many Elapsed Hours (8869), but I cannot see burning-in effects. I did shift the image up and down, but no effect. So that looks good. I will try to get inside and find the monitor brightnes/bias pot. Must be there I think. I do have the service manual with CLIP from Artek but I still have to have a look at it.
Did you already investigate further?

Jaap PA0JRK
Netherlands

 

8560E - the display characters are not so good

Hi Dan and others,

Found the problem, at least in my case. It's the DISPLAY CUTOFF adjustment. I did not adjust anything else for the time beeing, just this one. It's on page 64 (PDF page 65) of the 8560E/EC Service Guide from December 1999.


I now have perfect looking characters again.
Give it a try Dan.

Jaap

 

Jaap - thank you that's a great find!
Now ....? how did you get to that control? I have the cover off and can't see how to get to that board!
Thanks
Dan
 

Hi Dan,
Assuming you download the User Guide from
Then we have the same page numbers.
On page 149 you can see how to place the analyzer on its side and continue reading on page 171 how to foldout the A2 and A3 boards.
In short you have to remove all the screws (several lengths) from the top board A2. Disconnect the two flatcable connectors at the back of the board for easier foldout. One is for the HPIB connector and the other is for the 85620A Mass Memory Module connector, both on the rear of the instrument.
Then you can foldout the A2 board and the A3 board will come along.? They have to come both.
Then you have access to the A17 board close to the rear end of the CRT unit.
Use a long plastic trimmer stick. Its's high voltage in there. Then proceed with page 64 from my previous message.
Be careful and good luck.

jaap
 

Hello everyone!

I had the same problem with my 8560E as Dan and Jaap. The text was almost unreadable in places, even with intensity up to 255. The trace and grid were fine. When I switch off the unit, the CRT flashes brightly as various voltages fluctuate. This led me to believe the CRT still has plenty of mojo, but might need an adjustment.

I followed Jaap's instructions exactly, and now the display looks like new! The side benefit is that an intensity of 200 is plenty in normal room lighting. With a bit of focus adjustment, everything is crisp. There's something about that display, the noise floor, the IF filter shape factors... I like it.

The adjustment proper is really simple, but getting to it, not so much. I was a bit reluctance at first, but Dan said it was well worth it. It's important to follow the disassembly/reassembly steps carefully, to avoid damaging wires and connectors. Everything is crammed in there, so if something doesn't move, there's a reason. The trimmer is labeled "CUTOFF" on the CRT housing, which I believe is third from the front. I haven't looked at the schematic, but I'm guessing this adjusts screen grid bias, but don't quote me. I used a plastic trimpot tool, the kind Bourns reps would hand out like business cards back in the day. It was small adjustment, not much at all to bring the text back to life. Now I could probably do the adjustment in my sleep. Feel free to contact me if anyone has questions.

My unit has logged over 13,000 hours and it's still going! I have read about possible "cathode poisoning" in these old CRTs, which probably does happen. I tend to think cathode emission will degrade over time, so some bias adjustment is needed after many years.

Thanks Jaap and Dan!
 

All,

Looking for trouble shooting guidance on my 8560E. I have owned this SA for several years and it has worked well. Recently I am seeing an issue that requires attention. The SA boots up with a clear crisp trace and graticule. When the CAL signal is connected to the input, I see the expected pattern on the screen. The problem is that the usual screen annotations and menus are not displayed. I can bring up some menu items by pressing keys on the front panel, however most of the usual text does not appear. Also no error messages. I have opened up the unit to inspect the A2 controller board (seems like the most likely location of the problem) and see no obvious? issues.

I did find after searching here a thread dealing with poorly formed characters etc but from reading through this, I think my issue is likely a different one, however, I will give this remedy a try. Any guidance appreciated.

Rick

K8EZB

?
 


?Rick,
Check the DISPLAY/MORE/ANNOT menu setting.? It may have been turned off.? Also check the FREQ DSP setting on that page.? If that is OFF, the PRESET key should restore normal display

If it is not that, the FDSP? OFF command may have been entered somehow.? I don't know if PRESET will clear it.
Here is the description from the User Guide:

The FDSP command turns off all annotation that describes the
spectrum analyzer frequency setting. This includes start and stop
frequencies, center frequency, frequency span, marker readouts, center
frequency step-size, and signal identification to center frequency. To
retrieve the frequency data, query the spectrum analyzer. To reactivate
the annotation, execute the IP command.

I don't know if you can execute the IP command without an HPIB controller, and I don't know if the PRESET key has the same effect.

--John Gord
On Thu, Feb 2, 2023 at 10:53 AM, Rick Boswell wrote:

All,

Looking for trouble shooting guidance on my 8560E. I have owned this SA for several years and it has worked well. Recently I am seeing an issue that requires attention. The SA boots up with a clear crisp trace and graticule. When the CAL signal is connected to the input, I see the expected pattern on the screen. The problem is that the usual screen annotations and menus are not displayed. I can bring up some menu items by pressing keys on the front panel, however most of the usual text does not appear. Also no error messages. I have opened up the unit to inspect the A2 controller board (seems like the most likely location of the problem) and see no obvious? issues.

I did find after searching here a thread dealing with poorly formed characters etc but from reading through this, I think my issue is likely a different one, however, I will give this remedy a try. Any guidance appreciated.

Rick

K8EZB

?

?
 

Success! I followed the guidance from Jaap above and now have annotations bright and sharp. I can run the intensity setting at 130 with excellent results.?

Thanks to all!

Rick
K8EZB
 

Hi Rick and John,

Great to hear that Rick. A lot more of these analyzers will perhaps get the same isue.

Good luck,

Jaap
 

PS: My 8560E Elapsed Time shows 60468 hours. No way to know if this is accurate as I have owned this instrument for only five years and have used it no more than 50 hours since I acquired it. In any event, it is working well as far as I can tell. Runs the self-diagnostics without errors, with sharp, bright annotations after the CRT Cutoff adjustment described above.

Rick
K8EZB

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