Author Topic: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin  (Read 7219 times)

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Offline Ice-Tea

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #25 on: April 23, 2019, 04:13:16 pm »
I wonder how long it took to develop the CMU200, considering its complexity and engineering...

Think the better question is "how big was the team" ;-)

Offline Bicurico

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #26 on: April 23, 2019, 04:31:02 pm »
Yes, of course. I meant "how long" in "man years"...

Still, it is impressive when you are messing inside a CMU200: so many modules, each with several boards, custom IC's, FPGA, software, etc.

Then all the PCB layout, circuit design, materials (silver plated modules, etc.).

I can't begin to imagine how much work, research, development went into such a device.

No wonder they were sold new at around 100.000 Euro (?).

Regards,
Vitor

Offline Ice-Tea

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #27 on: April 23, 2019, 06:00:31 pm »
Pretty sure for 100k you got a base unit and not much else...

Offline Bicurico

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #28 on: August 21, 2019, 08:31:03 am »
Yesterday one of my CRTU units booted first fine. Then I switched it off but remembered I needed to measure something else, so I turned it on again. Unfortunately the serial number recognition during BaseDiscoveryOptions took much longer than usual and the dreaded error message appeared.

Strange, though, it said "error# 1095 overlay.c system error" instead of the usual "dsp.c" error.

I restarted and then the CRTU booted OK, but on successive boots, even after one night off, it now always produces this "overlay.c" error.

I don't have the time and nerve right now to start swapping HDD and DIGITAL board, though I am pretty sure this will be DIGITAL board related.

Any idea what this could be?

It disturbs me that these fine units are starting to fail due to the DIGITAL board and the small PCB's attached inside, which are basically impossible to repair.

Regards,
Vitor
« Last Edit: August 21, 2019, 08:43:52 am by Bicurico »
 

Offline Ice-Tea

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #29 on: August 21, 2019, 09:17:18 am »
If you figure out which board crapped out, contact me. I can probably offer a spare.

Offline Bicurico

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #30 on: August 22, 2019, 08:38:16 am »
Update:

Swapped DIGITAL board with a known good unit --> same error message! This is NOT related to the DIGITAL board...
Run scandisk and defrag from Service Menu --> No issues found
Swapped HDD with one of another CRTU --> device booted OK, but with fW 3.x instead of FW 5.x (which was active on that HDD -> because of compatibility with Windows 2000 partition)
Went inside Service Menu and installed "Another FW", selecting an alternative FW5.x version (less options installed) --> device boots OK on the original HDD

Conclusion: I think some file/data got corrupted and reinstalling the FW fixed it?

Strange...

Regards,
Vitor


Offline Bicurico

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #31 on: August 22, 2019, 09:01:39 am »
Another update:

It is not the HDD or some file corruption.

Activated the original FW5.x with many options and the error comes up again!

So now I come to the conclusion that this error is related to some hardware option that got broken. If the FW does not have support for said option, the unit powers up ok.

Back to FW 5.x with just the GSM option, the device works ok.

Since I swapped the DIGITAL board, it must be some other board/module.

This is a 83 unit. The other broken unit I have is a 82 unit, so I cannot swap all boards, as they are different. I don't want mess with the other working units (CMU200 and CRTU 82).

I don't suspect the RXTX board at this moment.

However, I would be grateful for any idea regarding which board/module might be malfunctioning.

As I really only use this CRTU for spectrum and signal generator, I will leave it as is for now until new ideas come up.

Regards,
Vitor

Offline niconiconi

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #32 on: April 28, 2020, 02:38:55 am »
I also encountered a similar problem, and the TL;DL version is: Be aware of the bad IDE ribbon cable!

While replacing the HDD with an SSD, I encountered the hang-on-boot issue on my CMU200. If the hard drive bracket was not screwed in, the boot always succeeded. But as soon as I screwed the bracket in, I had a hang-on-boot problem, sometimes with random system error messages!  :wtf: :wtf: :wtf: It turned out that the SSD enclosure was little bit shorter (or longer? I'm not sure) than the equivalent HDD, so when the hard drive bracket was fully mounted, it put a lot of stress on the IDE ribbon cable and bent it to a sharper angle, causing an intermittent electrical connection, creating the random hang-on-boot issue. If anyone else has similar issues, I think it's a good idea to also check the IDE cable - one way to test it - unscrew the hard drive bracket, flip the HDD, and let the HDD sit on top of the screen with the PCB pointing up (be careful not to accidentally hit or short the HDD while it's spinning), and see if the boot succeeds. If so, the IDE cable is bad. If system failure is mysteriously fixed after removing and reinstalling it back, this can be a reason.

Another issue I encountered was a black-screen-of-death problem when entering Version Manager (even with the original disk), it really drove me crazy - I don't have any of the original installation medium! Scandisk didn't help. But my PC intuition told me it was likely a software compatibility problem, and it could be fixed by using the most ancient way to access the disk. First I entered BIOS and tried setting the HDD access mode from Auto to CHS, and set its speed to PIO 0, the slowest configuration possible. But it just led to an error on boot - CHS is too ancient, so I changed CHS to LBA. And the Version Manager came back to life. So, LBA + PIO 0 is also worth trying.  :-+ The side-effect is an extremely slow disk access, but it can always be changed back after troubleshooting.
« Last Edit: April 28, 2020, 02:46:37 am by niconiconi »
 

Offline Radiosonde

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #33 on: December 23, 2020, 05:58:53 pm »
Hello
I now have a CMU200 with a similar problem:
The unit boots up, which it does really slow, if I want to go into "Version Manager" it just shows me a black screen until i turn it off again.
If the unit comes on eventually everything seems to work, altough the cursor sometimes lags, but when I turn on "spectrum analyzer" the CMU shows me a red warning which says:

System Error
....
Filename: tsk.cpp
Line: 2146
....
Add. Info
Str: ISR_C:HWIRQ::get_actual_stack_frame_number()

Can anyone give a hint on what this exactly means?
Help would be very much appreciated.
 

Offline Ice-Tea

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #34 on: December 23, 2020, 07:47:44 pm »
With such erratic behaviour I would firstly:
- check all ribbon cables. A lot of people have been bitten by badly inserted cables, and there are a lot of them
- the "computer board" (which is right behind the display) sometimes suffers from worn out capacitors. Check them. That would fit rather well with bad boot behaviour.

Offline richnormand

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #35 on: December 23, 2020, 10:29:04 pm »
"sometimes suffers from worn out capacitors. Check them."
That would be appropriate indeed.
On mine the small fan was completely seized up. I had to test all the caps but only found one that was marginal. There was a tell-tale temperature sticker on one of the chip that was indicating an overtemperature to its max indication.

Also some of the ribbon connectors were at an angle. So I systematically reseated everything on the whole unit that I could get my hands on.

REPAIR, RENEW, REUSE, RECYCLE, REBUILD, REDUCE, RECOVER, REPURPOSE, RESTORE....
 

Offline Radiosonde

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Re: CMU200 Rohde & Schwarz hangs during BaseDiscoverOptionsBegin
« Reply #36 on: December 31, 2020, 10:12:46 pm »
Thanks for the hints so far, and a happy new year all around!

I did so far:
Cleaned all modules and checked all connectors
Replaced BIOS battery etc.

I found that one module on the DIG board causes the CMU to hick up, as described above.
I started with removing all extra modules from the DIG board, now the CMU boots up quick as normal an even passes selftest, as long as it doesnt get to a "spectrum analyzer" function, here it will show me an error "dsp.cpp" "ddc_drv" or similar.

According to the service manual the DIG board hosts the following modules:
-ADC
-DDC
-TXDSP
-AUC (directly above TXDSP with the cooling mat on it, havent marked it in the image)
 
it is possible to have each module twice as an option, therefore the extra connectors.

The unit boots up normally only if the DDC module isnt fitted, otherwise it will take an eternity..
As said, without the DDC module everything seems fine until I start the spectrum analyzer or the unit itself tries to do so (selftest) which seems logical as the DDC module is there to preprocess the datastream it gets from the ADC.

From the service manual: (courtesy of Rohde & Schwarz)

"The sandwich DDC MODULE1 is directly plugged onto the DIGITAL
BOARD via three multipoint connectors and processes the digital data
stream of the receiver. In a special ASIC chip, the I/Q shaping, the
matching of the data rate and the respective filtering (bandwidth
shaping) of the digital data stream are produced. Then follows a DSP
(RX DSP) with further evaluation of the digital I/Q data for
measurement purposes. Besides, the digital I/Q data are passed on via
the MOTHERBOARD1 to the LINKHANDLER MODULE for evaluation."

I started to reverse engineer the module, and checked all the supply voltages which seem to be correct.
So I guess this isnt repairable at all, at least not without schematics and programmed spare parts.

What would the experts do?
Change the whole DIG assembly or is there a way to get hold of just the DDC board?

Regards
[attachimg=1]
« Last Edit: December 31, 2020, 10:15:14 pm by Radiosonde »
 


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