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TDS684C won't boot anymore

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Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

TDS684C won't boot anymore

Post by Belgarath » September 29th, 2018, 6:08 am

Dear Tek lovers,


My TDS-684C finally not booting anymore. This is where I’m stuck after many bumps with this (fine) scope. I really need some help from the experts here...

When it came home, the booting was unreliable : booting 1 out of 3. It, then worked fine, but after a certain amount of time on (around one hour), the screen froze. I might shut it down and reboot, and it freezes later again, and again.

I changed all the tant caps, with no differences and place on socket a new NVRAM chip (DS1250Y). This helps for a while the scope booted and worked fine couple weeks until the point it won’t boot up anymore.

Now, the scope starts until I get a small clock on the screen and it stops there. All the front panel leds are lit.

After soldering an adapter for the opt13 this is what the console port told (same log every boot attempt) :


beginning_of _log

RUNNING FROM DRAM.
DRAM test passed.


Bootrom Header Checksum passed.
Bootrom Total Checksum passed.
BootRom Check Sum passed.
Bus Error Timeout test passed.

Kernel Diagnostics Complete.

Calling SDM (monitor) Routine.

Enabling Bus Control register. Value = 0x67
IMR 1 Register test passed.
Misc. Register test passed.
Timer Interrupt test (Auto-Vector) passed.
NVRam DSACK test passed.
NVRam Write protected.
Flashrom DSACK and JumpCode test passed.
Flashrom Checksums passed.

Bootrom Diagnostics Complete.


DipSwitchValue: 0


Skipping boot loader.
Transferring control to FlashROM.

No PCMCIA option board detected.
FLOPPY: Detected

Adding 5994 symbols for standalone.


CPU: 68EC040. Processor #0.
Memory Size: 0x1000000. BSP version 1.0.

Executing Diagnostics
-> Start Power-On Diag Sequence
hwAccountant probe routines
Probe for unexpected pending ints
Dsp Instr mem size
Dsp D2 mem size
Dsp D1 mem size
Dsy Vect0 mem size
Dsy Vect1 mem size
Dsy Wfm0 mem size
Dsy Wfm1 mem size
Dsy Text0 mem size
Dsy Text1 mem size
Acq number of digitizers
Acq mem size
Cpu timer interval uSec
Cpu Dram size
NvRam mem size
Opt Math Package presence
Opt RS232/ Cent presence
Opt 1M presence
Acq Intlv Cal Id presence
Opt TvTrig presence
Opt TvTrig index
Dsy color presence
Opt floppy drive presence
Opt hard drive presence
Acq limited bandwidth presence
Acq number of user channels
dspForcedBus ................... pass
cpuDiagD2MiscReg ............... pass
cpuDiagDSPIntMaskReg ........... pass
cpuDiagDsyAccess ............... pass
dsp68kMemTest .................. pass
cpuDiagFIFOMem ................. pass
dspRunVerify ................... pass
dspBusRequestTest .............. pass
dspImplicitBusAccess ........... pass
dspTristarMemTest .............. pass
dsyRastModeV0Walk .............. pass
dsyRastModeV1Attrib ............ pass
dsyWaitClock ................... pass
cpuDiagAllInts ................. pass
nvLibrariansDiag ............... ***FAIL***
..error details:
ERRORID: 163 diagnostic test failure nvLibrariansDiag
Libs with crcc failures:
IntConst, State

calLibrarianDefaultCk .......... pass
checkIfCalFailed ............... pass
dspForcedBus ................... pass
acqProcThermistor .............. pass
digRegisterDiag ................ pass
digAcqMemDataDiag .............. pass
digAcqMemAddrDiag .............. pass
trigGtlRegisterDiag ............ pass
trigBtlRegisterDiag ............ pass
ch1EdgeTrigDiag ................ pass
lineTrigDiag ................... pass
dlyTrigDBTRunsAfter ............ pass
slewrateTrigDiag ............... pass
trigAttenSerialReg ............. pass
trigPreampSerialReg ............ pass
trigDTCSerialReg ............... pass
trigExtlSerialReg .............. pass
trigDacSerialReg ............... pass
TICountersDiag ................. pass
gtlBigCountersDiag ............. pass
trigBtlConfidenceDiag .......... pass
glitchTrigDiag ................. pass
pulseWidthDiag ................. pass
digRegisterDiag ................ pass
fpDiagConf ..................... pass
optDiagPM110Reg ................ pass
optDiagFloppyCacheMem .......... pass
optDiagFloppyControllerIO ...... pass
optDiagFloppyDrive ............. pass
optRS232DuartIO ................ UNTESTED
optRS232DuartIntLoop ........... UNTESTED
optCentronCntrlReg ............. UNTESTED
optTv8bitRegDiag ............... UNTESTED
optTvShiftRegDiag .............. UNTESTED
optTvXparentCodes .............. UNTESTED
optTvDontCareCodes ............. UNTESTED
optTvEdgeAndLevel .............. UNTESTED
optTvSyncLevels ................ UNTESTED
Executing Smalltalk
hwAccountant probe routines
Probe for unexpected pending ints
Dsp Instr mem size
Dsp D2 mem size
Dsp D1 mem size
Dsy Vect0 mem size
Dsy Vect1 mem size
Dsy Wfm0 mem size
Dsy Wfm1 mem size
Dsy Text0 mem size
Dsy Text1 mem size
Acq number of digitizers
Acq mem size
Cpu timer interval uSec
Cpu Dram size
NvRam mem size
Opt Math Package presence
Opt RS232/ Cent presence
Opt 1M presence
Acq Intlv Cal Id presence
Opt TvTrig presence
Opt TvTrig index
Dsy color presence
Opt floppy drive presence
Opt hard drive presence
Acq limited bandwidth presence
Acq number of user channels
can't open input 'fd0:/startup.bat'
errno = 0x13 (S_errno_ENODEV)

Smalltalk/V Sun Version 1.12
Copyright (C) 1990 Object Technology International Inc.

system primitive failed
2(18)>>181207152
2(18)>>378011763
2(23)>>'Unknown method'
310>>373754701
210(119)>>239536962
210>>279511171
66>>279511171
310(62)>>213581967
310>>279511171
66>>279511171
171(62)>>213581967
171>>215680458
171>>222495163
297>>353113443
[] in 298(23)>>'Unknown method'
156(23)>>'Unknown method'


end_of_log


Not easy to decipher without the proper glossary, might it be a corrupted firmware ?


Best Regards,

François
Last edited by Belgarath on September 29th, 2018, 9:02 pm, edited 1 time in total.

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » September 29th, 2018, 6:33 pm

Hi Belgarath,
The TDS600C series should have a DS1486 NVram chip as well as the DS1250/DD1650 chip. I believe it is the same CPU board as the 500/700D series. The DS1486 is the primary holder of the NVlibs. The actual calibration is carried on the ACQ board (unlike the "A" series), but the error looks just like some I have seen on other TDS5/700 D series boards with failing NVram. Look an see if you have a DS1486 chip.

If the DS1486 chip is the original, it needs to be replaced, just like the DS1250 you mentioned.

I'm sure I have plenty of 500/700D series images for the DS1486. I'll be happy to post it, if you want to load it. I'll send instructions after you verify you have the DS1486 chip...

Issue is, you may have to calibrate the scope after you image it. If you have the right gear, it's easy. Otherwise, not so. Anyway, even without calibration, I'll bet the scope works just fine, just may not be quite as accurate as specified.

Strick

Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

Re: TDS684C won't boot anymore

Post by Belgarath » September 29th, 2018, 8:56 pm

Hi Strick,

Thank you for sharing your expertise and time.

You are right, there is a DS1486 chip just aside the DS1250Y. My cpu board is labeled 679-4349-00. I already changed it for a new one, and put it on socket for easier maintenance.

So I'll be very happy to get an image and load it per your instructions (but for now my chip programmer knows the DS1250Y, but not the DS1486...).

About the calibration, I might find a way. For the voltage and low/mid speeds I own a calibrated Tek rack with TG501, PG506 and SG503, as well as HP3456A precision voltmeter and a couple RF generator. I do not have in lab, yet, a hpib interface but it's a planned purchase.

Best Regards,

François

EDIT : BTW I didn't mention the DS1486 in my initial post because I thought it was only a timekeeper.

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » September 30th, 2018, 7:57 am

François,
attached is a zip with two files for the DS1486 - one is from a 540D and the other from a 544D. Either should work. The files are listed as .dat files, but they are really .bin files and you should rename them.

The DS1486 is really the important chip, not the DS1250/1650. I have seen real garbage (or nothing at all) on this chip, but if the 1486 goes, the scope won't boot properly.

If you use a programmer, the DS1486 has the same architecture as the DS1245 chip. You should have that in the writer's library. You need to load the file and use a device offset of "D" as the first D bytes are used by the clock. If you can adjust the speed, write at a moderate speed. If the write fails at the start, the offset isn't working or the chip is bad. If the write goes through, but the verify fails at the very end, it's ok, give it a try.

Another method of writing to the chip is to install it and write to the address 0x4000000 using tektool. You need a GPIB card and cable to do this and the executable program tektool. If you have the card and cable, but can't find tektool, let me know and I'll send it.

A final method is to use the serial debug port (OPTION 13) that you used before. do a "help" and you should see all the commands - they are also listed elsewhere in the forum. You just write the file to the same address.

good luck! Strick
Attachments
TDS540D_4_2.zip
(32.31 KiB) Downloaded 301 times

Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

Re: TDS684C won't boot anymore

Post by Belgarath » October 1st, 2018, 1:29 am

Hi Strick,

Thanks for the infos and the files. Well... It seems I am out of luck for this one !

For now, my best guess is that my DS1486 has a strong personality disorder : sometime I can read it, sometime not. The status is probably bad chip, and you were right, there is definitely something wrong in this part of the scope.

This DS1486 is supposed to be a "new" one I bought couple years ago on eBay, so there is suspicion here. And I can't find the old one, I shouldn't have discarded it, but so much mess overhere.

I guess I will have to find another DS1486 and test.

There is also this interesting option :
https://www.ebay.fr/itm/Tektronix-TDS78 ... 2591784518
not so cheap but if it's working it might worth it as a sound solution for our scopes.

I'll keep the thread updated as soon as there is something new.

Best Regards,

François


EDIT a couple hours later : Finally found in my trash bin the original DS1486. Plug it in and... Tadaaa !!!

This was a bad idea to get a new (junk) one, my lesson is : I won't trash anything anymore :)

I finally purchased the two chips I quoted earlier, it would take a couple weeks to get them and test them. I'll post a report then.

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » October 1st, 2018, 5:28 pm

François,
That's real good news! Before you do anything else, capture an image of the the memory from 0x4000000 for 0x20000 bytes. That's what your chip holds. I assume you already did that, but that's the image that matters, not the ones I sent.

You could probably do it using the DS1245 setting in your rom burner. Just don't try to write to it.

I've bought at least 40 DS1486 chips from China. Some work, some don't... It's simply not made in the states anymore.

Also, you can dump the memory to a file using the Debug port.

Like I said before, the DS1250/1650 is secondary to the DS1486.

good luck. Strick

Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

Re: TDS684C won't boot anymore

Post by Belgarath » October 1st, 2018, 11:48 pm

Hi Strick,

Yes, I did backup my DS1486 :)

For now, everything appears to work fine except the SPC which report one error and fail (tried 10x) :

Cal meas clipped at min dig on ( [email protected] f003 ): -5.080 divs

So, I still have something to fix on the fourth channel… There are interesting threads on eevblog on that topic.

What’s complicated with those scope is the scattered technical info and that Tek didn’t release software, firmware, etc. Hopefully, because of tek users an lovers, there is almost everything on the various forums.

Once again, thanks for helping.

Best Regards,

François

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » October 2nd, 2018, 9:03 am

Francois,
those types of SPC failures are usually due to too much resistance in the Attenuator relays for that channel. i recommend you simply exercise the relays for channel 4 by switching from 1volt to 2volts and 100mv to 200mv a few dozen times. you should hear the relays click each time.

I actually have a script that I run that uses the GPIB command IBIC to cycle all the relays using the commands: 10v, 1v, 100mv for each channel in sequence. That way I don't have to wear out the voltage pot. In extreme cases, I remove the offending hybrid and cycle the relays hundreds of times using a 12 volt power supply. I've only replaced a couple of relays in the dozens of scopes I've dealt with.

Strick

Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

Re: TDS684C won't boot anymore

Post by Belgarath » October 2nd, 2018, 7:41 pm

Hi Strick,

The third and fourth channels are usually seldomly used on my scopes, this is indeed no good for low signal relay contacts. I took the time to unmount the four hybrids and clean everything with isopropyl, no change after re-applying power.

I challenged the relays hundred times as you recommended with no change, so I’ll buy new ones and swap them, they are no expensive parts.

An additional question.
At boot, something is weird in the banner, it states :
TDS 684C (FV:v5.1e)
Options: 13 1F 1M 2F

But 1M doesn’t exist for TDS684C !
Might it be an incorrect firmware implemented ?

Best regards,

François

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » October 4th, 2018, 8:41 am

Well,
I have see attenuators that simply would not pass SPC properly. Even with properly low resistance on the relays. I finally ended up replacing the whole attenuator as the error could be in the permanently mounted IC on the attenuator.

If you check the voltage at very low levels (100 mv input or a 10 mv input), you can usually spot the error on the scope screen and this may point to the 1x, 10x or 100x relay that is high. checking to make sure the relay is working from 1V to 2V (10x to 100x) and 100mv to 200mv (1x to 10x) is easy.

Resoldering the relay contacts sometimes works and sometimes not. I've also found that the layer connections (the little circles or dots) that connect the top to the bottom can sometimes become highly resistant. I've fixed a couple of attenuators by applying solder to the circles (50 ohm part was 52 ohms).

If you do replace the relays or whole attenuator, I suspect TEK would want you to do a calibration. Unless you work in really high freqs, the CVR cal is probable all you really need to do as the high freq cal for the 684C jumps from 10mhz directly to above 600 mhz and then works up to 1GHZ. If you do work with freqs above 500 mhz, you really do need to do the cal or the levels may be off on the repaired channel. I was amazed at how much control the calibration software has on the indicated level of the input signal...

good luck.
Strick

Belgarath
Posts: 6
Joined: September 29th, 2018, 1:01 am
Country: France

Re: TDS684C won't boot anymore

Post by Belgarath » December 1st, 2018, 8:07 pm

Hi Strick,

Sorry for the delayed feedback, I’ve been quite busy overhere.

My TDS684C is finally up and fully running.

The replacement modules for DS1250Y and DS1486 built/sold and firmware loaded by David ( https://www.ebay.fr/itm/302913384290? ) are working perfectly. I think this might save a few scopes which are currently the dead in the field, and it’s definitely the solution I would favor in the future rather purchasing unreliable DS chip. I spent too much time and money with those bad DS chips...

About the calibration, and following your advice, after unsuccessfully challenging the relays, I checked again the soldering and reflow a few of them. It’s now working and the signal path compensation works fine.

Thanks again for your help on this matter.

Best Regards,

François
Attachments
IMG_2980.JPG
IMG_2980.JPG (1.88 MiB) Viewed 5746 times

strick
Posts: 110
Joined: March 22nd, 2016, 11:23 am
Country: United States

Re: TDS684C won't boot anymore

Post by strick » December 2nd, 2018, 4:04 pm

François,
That's great news! Actually, I have had mixed results with the DS1486 and DS1650 chips from Asia. I did find a couple of sellers on Ebay that seem to send me good stuff - If anyone is interested in who they are, please send me a PM as It's not nice to tell...

I used to use a programmer to program the chips, but the DS1486 will always complain and in the 540D and later series, results in a cal failure. While that's no big deal to me (I calibrate them for fun...), most folks don't have the gear and DOS computer with GPIB.

Now, I use Tektool to grab the image and Tektool to write back the entire memory from 0x4000000 to 0x4fffffff. Now the only difference is the time signal that is on the first couple of bytes of the DS1486. No recal needed...

Anyway, it's nice that folks have two ways to go.

Strick

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