Hacking/Upgrading old scope (TDS754D)

[nctnico]

Dammit! I just sold my TDS510A a couple of weeks ago. Having the 2F option enabled might have increased it's value 

[Andy Watson]

Dammit! I just sold my TDS510A a couple of weeks ago. Having the 2F option enabled might have increased it's value 

I can tell you with 100% certainty that this upgrade worked would have worked on your ex 510A.

[AwArD_RzD]

Well took more than a month to receive the Nvram but i have some interesting result.

Before doing the hack i did a backup of the Nvram so no 2M option or 2C. I did the hack and after everything was unlocked and working. Today i programmed the new Nvram with the original non hacked data and well the option still there after a reboot, so if i didn't by error replaced the original backup with the hacked one i can confirm the option are not stored in the Nvram. Well i don't know really what stored there because i don't have any data mismatch when i compare the two even after 1 month of use and test.

Maybe it's all in the te28f160 flash IC? anyway i hope this will help anyone who want to try the hack.

[andy2000]

Well took more than a month to receive the Nvram but i have some interesting result.

Before doing the hack i did a backup of the Nvram so no 2M option or 2C. I did the hack and after everything was unlocked and working. Today i programmed the new Nvram with the original non hacked data and well the option still there after a reboot, so if i didn't by error replaced the original backup with the hacked one i can confirm the option are not stored in the Nvram. Well i don't know really what stored there because i don't have any data mismatch when i compare the two even after 1 month of use and test.

Maybe it's all in the te28f160 flash IC? anyway i hope this will help anyone who want to try the hack.

I'm pretty sure the options are stored in the Dallas clock chip.  The main NVRAM is used for things like stored waveforms, SPC, and probe cal. 

[AwArD_RzD]

Repair thread https://www.eevblog.com/forum/repair/tds754d-not-booting-anymore/


Well that didn't last long...    

Did some test worked great power off the scope, take a 1 hour eating break. Baby sleeping still have time to do more test, power the scope go to the bathroom 2 min come back, all the led still on, no screen, no response. Reboot same thing.... 

Reopen the scope led display stuck to .8, if i cycle the unit fast sometime i have a .E , or a .8 .E .8 sequence showing very fast or a weird c (a,f,g segment on).

what i did before (for anyone not following this post), Hacked the scope for the 2m 2c option, worked great for a month till today, replaced the ds1250 Nvram by a fresh one with the backup of the old one.

Troubleshooting.
2 fan blowing on the scope case open.

-Tried to cycle the scope many time.    Same thing
-Replaced the fresh nvram with the old working one.   Same thing
-All the cable are tight in the right slot.
-Waited 5 minute, same state, tried to talk via GPIB, got an error, the scope dosen't reply..

Start to read the service PDF.

-All voltage OK
-All voltage look good on my other scope.
-Frequency good at the pin 25 of the J2 connector.
-Tried the s1001 switch with the help of some other post on the Tek forum. Same thing.
-Tried many combination with other board removed. Same thing.

With all the troubleshooting and following the flow chart the only thing this manual screaming is Replace the A11 DRAM Processor/Display module.

Checked the thermal signature with my E4 and nothing weird show up... No cap leak and nothing out of place visually.

I have the impression that the cpu is stuck on reset or briked. I tried to probe the Nvram to see if the CPU toggle the CSn pin and nothing happen.....

damn.. never again ... if it ain’t broke, don’t fix it     

For now i have a 16 Kg paper weight, if someone have an idea....

[Mosaic]

need advice on replacing nvram on a 694c. anyone has pics or a clip doc.? mine is still alive.

[Vince]

Any news on this repair ? Been almost 2 years since  the last message, but none the less I am still curious about it ! Were you able to repair it in the end ? What was the cause of problem exactly ?

[PrecisionAnalytic]

Repair thread https://www.eevblog.com/forum/repair/tds754d-not-booting-anymore/

I have the impression that the cpu is stuck on reset or briked.

Eh, any progress?

[AwArD_RzD]

Sorry for the late reply but life and stuff

I still have the scope but unfortunately it still broken, I bought another TDS754 and i have keep the dead one for spare part.

For what i remember i was able to talk to it via the serial interface (the hack where you use the CPU board edge connector with the serial interface) so i'm sure that the Cpu was not dead but it seem that i maybe zaped something or did some damage to a IC inside when i have put the scope back in is case.

I found that someone replied to me in the TEK forum https://forum.tek.com/viewtopic.php?t=138426

I remember to have seen that but i never completed any troubleshooting because i had my first child and it seem time fly when that happen So it seem that the problem is or affect video memory on the cpu board from the log i posted.

I'm about to buy a house,  i will have more space and i will probably dust off the scope and look at it again on the side but for now i'm designing a power amplifier and this take much of my time and bench space. In the last 3 year since the problem i was able to get many stuff about the scope (PDF, Schematic) that i didn't have in 2015. The price for used part seem to have lowered too maybe i will buy the cpu board and see if it boot and start from there.

I'm not very active on this forum (well on any forum) so i don't except to post any update soon but i will give update when i go for it.

Thanks for the interest.

[Vince]

Thanks for the update 

[madao]

Is there a problem to read the nvram with the TL866CS ?

I updated the minipro software in preparation for the backup but it seem the software only test the DS1250, when selected, a windows open to test the device, but you can't read or write on it, if i select the other dallas ic now all the option to read write test are enabled.

There some ic with RW and test in the name but the ds1250 is the only option i can choose. I don't have the chip so i can't know if it's just a test and after the option are enabled.

Anyone have a clue about that, the device is listed to be compatible with the minipro but compatible to what extend.

Thanks !!

Today have i using this tools.

Dumping of  NVSRAM , it run fine.
But writing of NVSRAM:    corrupte file 


I have desoldering DS1486 and writing him with TL866A  (choosing  DS1245Y ) and it is a success.
(Wrong time is not really a problem :-).

O'scope is  TDS754D with old acquisition board (C-Typ, 672-4041-00) and new CPU Board (671-4349-00)  FW: 6.6e

regards
Matt