Author Topic: W&G sna-20/23 spectrum analyzer repair  (Read 13754 times)

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Offline NIKGEROS

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #25 on: December 17, 2020, 06:34:03 am »
Hello again , best greetings to all.
I think you need the model and is SNA-23 with a 8 MB memory....

tnx a lot
 

Offline NIKGEROS

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #26 on: March 09, 2021, 11:18:54 am »
Hello again !
Think I'm facing same problem here...Probably have f series SNA23...not a HDD....
Post some pic....In case somebody resolved that pls inform !

Take care
 

Offline Qw3rtzuiop

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #27 on: March 09, 2021, 02:38:34 pm »
Your HDD is probably dead. If you install an new one you can use the image from xdevs.
 

Offline NIKGEROS

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #28 on: March 11, 2021, 07:39:00 am »
thank you so much !

take care,
Nikos
 

Offline NIKGEROS

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #29 on: March 16, 2021, 12:42:09 pm »
My model  is C series...I can not find a HDD....Do you have any suggestions ?
thank you
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #30 on: September 01, 2021, 11:07:18 am »
The C series does not have a HDD. Instead it has a lithium-buffered CMOS RAM. The Lithium battery is the orange Renata thingy on the larger top board. There is also a Dallas 12887A realtime clock chip with some CMOS RAM that has an internal Lithium battery that may go empty. It is used to keep the bios settings in the usual PC AT way. Changing the CMOS RAM battery should be done with the SNA33 powered up, otherwise the content of b: is gone for good. (Supposed the Li Battery is not yet empty.)
I have found the user manual, service manual and schematics somewhere as PDFs.
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #31 on: September 13, 2021, 09:31:34 am »
There is more to the disks.  (My serial number is D0029.)

For those without a real harddisk, C: is an array of Flash eproms that can
be written with an utility from the service disk. It is R/O to the normal user.
B: is the lithium buffered cmos ram for user results and calibration factors.

I also get the message that the HD controller is broken. But when I boot
from floppy, I can see the contents of C: , so this seems to be more a
driver issue. I cannot boot completely into the measurement program.
All floppies must be dos6.22. Everything else seems to produce
wrong_version errors. Some .com and .exe  and .sys files are incompatible
when taken from different dos versions.

I replaced both the Renata Lithium battery and the Dallas Li buffered real time
clock and managed to erase b: during that, should not do that in the night.
I then tried to set the clock and disk type in the Dallas chip. I could find the required
disk type nowhere in documentation.  I finally restored the original Dallas chip,
and it seem not to be completely empty.


It contained HD type = 8, which is
Cyl  995   heads 14    WPCOM 65535    LZONE 995    sect 17   Size 116 MB

Funny enough, the old Dallas had the same time that I set with the new chip,
but I think I must not understand everything. In NIKGEROS' case, the
Dallas chip seems to be empty because it has forgotten the date/time.

I could not get an original Renata battery in time, so I cracked the old one open
and soldered wires to the leads of the carrier. Don't solder directly to a Lithium
battery that does not have wires or tabs, that might result in a thermonuclear surprise.
I used a 2/3 AA cell with wires, ugly but works.

Sometimes, I also get the display with the zebra stripes from the first post,
so this is not a hardware malfunction. Also, my reconstructed boot disk has a
problem with the display window size. I cannot see the bottom line, so typing
commands is a royal pain.

The Wandel&Goltermann fan group on groups.io seems to be dead.
I see there abt 3 posts, and my test post never showed up.

cheers, Gerhard
« Last Edit: September 13, 2021, 09:36:44 am by Gerhard_dk4xp »
 
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Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #32 on: October 21, 2021, 11:02:38 am »
Thanks for all the information and contribution in this thread - I bought a SNA-23 today with the same HDD controller issue. I opened the box up onto to not be able to find a HDD, so I'm assuming I have a flash model. I've bought a USB Flash to Floppy adaptor which is the same form factor as a floppy disk drive, so I might upgrade the box with some modern hardware, we'll see if it works...
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #33 on: October 24, 2021, 01:37:32 am »
congratulations!

Make backups of the software on it before you start playing with batteries,
and also the bios settings.
(I would appreciate a copy :-)  it fits into an email nowadays.)
Maybe we should have a repository somewhere of the essential disks and proms.

I have paused the work on mine, tried to set up a different computer with DOS6.22
and a real hard disk, but it keeps power cycling. The kind of results you get when
trying to revive hard & software from the early monolithicum.

And don't think that "format" from 6.0 works with 6.22. It just says "wrong version"
but not what version it is, let alone what it wants.

cheers, Gerhard

 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #34 on: October 24, 2021, 01:42:16 am »
BTW I tried to contact the owner of the WG group on groups.io.
No response yet.

Gerhard
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #35 on: October 24, 2021, 06:26:16 am »
Thanks Gerhard!

So are you saying that the WG software is based on DOS 6.0? I'm having a very difficult time making a boot disk, naturally if I dump linux (All in One) onto a floppy it boots fine, but getting DOS or these files in the "Service Disk" on XDevs to boot is another issue entirely. Does anyone have a .img file of the service disk I can just _dd_?

Alex
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #36 on: October 24, 2021, 09:14:37 am »
I think it is 6.22.
I can send you my files, but no guaranty that anything works.
My address is  #dk4xp#at#arcor#.#de

Cheers, Gerhard
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #37 on: October 24, 2021, 10:05:04 am »
Alex, the mail to you bounces b/c of dangerous contents, even with zips.
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #38 on: October 24, 2021, 10:13:05 am »
Hmm, that's weird. Maybe easiest to upload to Google drive and share the link or dropbox?
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #39 on: October 24, 2021, 11:47:58 am »
So having not properly read the service manuals I thought there was reference to my HDD Controller Issue being connected to the SRAM B: drive. I managed to get a DOS 6.22 disk imaged and copied the service disk files across. In the process I have formatted my B: drive, whether or not it was already empty is another question entirely. DIR on B: read nothing previously and after the format. The seller of this unit mentioned that when he bought it, it came with floppies which he may still have and is in the process of packing up everything in his house, so we may have luck there.

I have the same challenges as Gerhard. I can boot into a DOS disk and see the contents of the C: drive, however, the unit won't boot citing a HDD Controller Error. Not sure what to do next
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #40 on: October 31, 2021, 05:31:13 pm »
Sorry, I've been away for a week.  The DOS files for the SNA are under:

<        http://www.hoffmann-hochfrequenz.de/downloads/sna_arch.zip               >

Seems like it is classified as a security risc also here  but can be overridden.

It won't stay there for long.
Looks like I have work to do on my web site.
Gerhard
« Last Edit: October 31, 2021, 05:51:17 pm by Gerhard_dk4xp »
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #41 on: November 02, 2021, 12:24:46 pm »
Thanks Gerhard,

I've downloaded it and am compiling a bunch of disks I'm slowly getting access to. I'll create a repo somewhere to share when I get it working.

On booting your disk I noticed the the same banding issue as the OP. I saw this was also the case when I started the SNA software from the C: drive from a DOS 6.22 disk. In breaking into a DOS shell with ALT+F10, I saw the debug errors which all cite the missing contents of the B: drive, I suspect these will go away when I get the image. By some stroke of luck I'm in contact with the person who has my calibration disk and hopefully I'll see it this week, we'll see.

I'll report back with status none the less.

Alex
« Last Edit: November 02, 2021, 12:35:45 pm by alexturner »
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #42 on: November 03, 2021, 10:50:56 am »
Does anyone have more of an idea about the zebra banding that occurs after the main-sw loads? Looking into the fairly scarce service manual it appears as if the AT board boots using VGA BIOS, however when the application loads there is a faster, application specific TI graphic chip that takes control and it's at this point the banding appears; so I suspect an issue here. The graphics board (BSK-3) is quite sophisticated and includes a switch to direct video to the EL display or the RGB TTL port on the rear of the unit. I suspect my best course of action is to purchase a TTL to VGA adaptor and see if I can get an image out the rear port (the diagnose switching, etc).

If not it appears the unit might be dead on a count of there being a couple of critical FPGA's which drive the EL display that firmware will be long lost to.

Have any of the original posters on this thread who have had banding issues on boot resolved this?

Alex
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #43 on: November 15, 2021, 12:55:21 am »
Does anyone have the install disks??
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #44 on: December 26, 2021, 03:56:06 am »
On microcontroller.net there appeared someone asking a question and in the context
it was clear that he has a working SNA23/33. I asked him for the floppy images but he
never resurfaced.

Tonight I took a floppy whose bit image is in the sna_arch.zip file that you should
have got. It tries booting into DOS but cannot find
\DOS\himem.sys
\DOS\country.sys
\DOS\ANSI.sys  and at least 2 other files.

The files are on the disk but there is no \DOS directory.
So I made one and COPIED them to that directory. The 1.44MB floppy is only abt.
half-full, and I copied also some more that are mentioned in config.sys and autoexec.bat.
I also commented out the first or second line in autoexec.bat that hides the commands
that are executed. I want to see them.

The floppy then booted into dos but I got the Zebra screen again.
I then rebooted and aborted it just before the W&G-specific things are started.
(many CTL-Cs).  That left me with a working DOS command line.
I can make DIR C:  or DIR B: and get the contents listed. That means that the flash disk c:
and the ram disk B: are OK.  I also did chkdsk c: and that worked ok.

Nevertheless, when I try to boot without floppy it says the hard drive is broken.

The bottom 2 or 3 lines of the built-in screen are missing, that's a royal pain. Use some
CR to see all the answers. Maybe a ANSI.sys param is wrong.
And I have a German keyboard while the system expects US.
That can probably be healed with the right parameters to country.sys. I wished I still had
my dos handbook.

I used a HAMA USB floppy drive to mount the floppy under Linux. The port must be
USB3 because that delivers more current to the floppy drive; else seek errors abound.
I'll make some screen shots tomorrow, too tired for now.

Cheers, Gerhard

« Last Edit: December 26, 2021, 04:07:41 am by Gerhard_dk4xp »
 

Offline alexturner

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #45 on: December 26, 2021, 11:06:17 am »
Thanks Gerhard!

So the SNA23 has two video controllers, a VGA graphics driver which is boots from, and another more advanced graphics processor which is used once the SNA software starts to drive the EL display. The issue (the Zebra lines) surfaces when the SNA software instructs the graphics card to switch and enable the EL display. I was able to validate this by running a command named BSK3 or something similar (which is the name of the graphics board). A more detailed explanation is available in the service manual.

I'm still not sure what these Zebra lines are about. I'm so surprised how few people have these and know much about them. They're such wonderful examples of engineering and it's a shame that our units are destined to sit on the shelf forever until more data surfaces. At this point, I'm looking for the install disks which should be floating around the ether somewhere - sounds like you'll benefit from them too but we'll see!

Alex
« Last Edit: December 26, 2021, 11:08:00 am by alexturner »
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #46 on: December 26, 2021, 01:35:40 pm »
I think the zebra banding is just uninitialized video ram; I have seen
similar effects with DRAMs fresh from power up.

At Leasametric they claimed a SNA33 did cost > DM100k anew, that
would be > €100000 now. 26 GHz and 1 Hz resolution BW.
Just build such a synthesizer.
« Last Edit: December 26, 2021, 01:40:32 pm by Gerhard_dk4xp »
 

Offline Pude

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #47 on: March 24, 2022, 12:56:10 pm »
Hello everybody,

I got a W&G SNA-33 from ebay yesterday and it has this problem with file system. It complains briefly about HDD controller.
I already hacked a new battery for Dallas RTC and Renata battery has voltage little over 3 V. Now I'm looking for a suitable boot disk for this. The disk drive works but I'm trying to use Gotek because the ease of use. I read this thread and maybe someone of you have some boot disks to start with? This machine didn't include any of those. If so I'll like to have an image, please. I tried a normal ms-dos 6.22 boot image, but no luck. Just for fun I tried to boot from an old Red hat linux disk, but it was for a machine I've scrapped many many years ago. :)

This machine does likely have flash version of C-drive. So any hints would be useful. Next I'm trying to find a keyboard for this, PS/2-kb should be fine? Some pictures below.
 

Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #48 on: March 24, 2022, 02:30:48 pm »
Welcome to the club!
I have made no progress in the meantime.

My keyboard is an old AT02 keyboard, cloned by Cherry. Works.

It is weird, that when booting it says that the c: drive is defective,
but when I boot from floppy and stop the autoexec.bat early enough,
I can see contents of c:

Booting from what I considered a boot floppy leads to the zebra screen.

Gerhard


« Last Edit: March 24, 2022, 02:45:29 pm by Gerhard_dk4xp »
 
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Online Gerhard_dk4xp

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Re: W&G sna-20/23 spectrum analyzer repair
« Reply #49 on: March 25, 2022, 10:06:30 am »
This does work also. PS2 keyboard + adapter cable.

What is the bios disk type of C: on your unit?

Gerhard
« Last Edit: March 25, 2022, 10:14:28 am by Gerhard_dk4xp »
 
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