[Solved]TDS3014 no trace no reponse of frontplate.

[madao]

Hello people.

 I got  a  TDS3014.

Fault:  Startup  complete.  Message "Selftest passed"      No  trace (despite  Auto-Trigger) and no reponse of frontplate.
Not one  LED is flashing while bootup.

Check of oscillator (48Mhz and 75,757 MHz) : OK
Check of oscillator from MCU on frontplate: dead.
Check with  new  4Mhz xtal: no oscillation.

I think: MCU of frontplate is dead.  Only reset line is asserted (from  low to high, while bootup.)
MCU is  NEC 78011
https://www.datasheetarchive.com/pdf/download.php?id=a9ce913475b09e2128212699d1690d1fab71bf&type=O&term=78011%2520NEC



Have you experience with this fault on TDS3000 Series ?
Has someone   frontplate for me ?  (bad encoder is not a problem for me :-) )

Greetings
matt

[daveyk]

Try holding in the B-TRIG button while it boots-up.  That forces a system RESET.  Fixed a few problems in the past.  Other than that, there is not repairable on those scopes. 

[madao]

This way doesn't work, because  MCU of frontplate is dead. No reactions and no oscillation on xtal.

[daveyk]

Sorry, I jumped the gun there.  I am very interested in these scope of own three of the (two TDS3052's and one TDS3054.  The TDS3052 were TDS3032s and my TDS3054 was a TDS3014).

I want to follow your repair in case I run in to it in the future.  The RESET line is NOT being held low on the processor correct?  I'm not sure how you could check the crystal other than replacing it.  Was it this way when you got it?  Perhaps it was dropped and the crystal broke?  I would think it's rare for a processor just to fail, especially hidden behind on a front panel board.  Its life is probably not stressed.  If you change the XTAL, and it is still bad, it's not an easy fix.  Is it the processor, external memory chip or some peripheral chip?

Let me know if you made any progress.

Dave

[madao]

Reset is  only line, which it is asserted. While bootup change reset line from low to high. It is correct.   No oscillation,  it is same after change of XTAL (orginal is 10 MHz type)

NEC 78011 is single chip MCU (all in one, same as Atmega).. this is why i need  other frontplate (bad encoder is not a problem)

Failure-cause: probably ESD-discharge/overvoltage on Tekprobe-Interface. Not one  voltage clamp on   TekProbe-Interface ( old TDS500/700 has Diode  as voltage clamp on I²C line)

Today, i 'll borrow TDS3012B and  check with their frontplate.

[madao]

It live,  old frontplate is  cause for this failure.
Frontplate is borrowed from TDS3012B .
Reason for no trace:  it was added with offset.. this is why: no trace.


Now  i am looking after frontplate with good nec 78011 MCU.

Greetings
Matt

[madao]

Next  failure:   Channel 1  100-200-500mV/DIV amplifier is dead.  It is found by intensive  check.
 I have thinked at this point: it was added mit offset.

Now , i know, why is  channel 1 and  frontplate broken:  overvoltage !    This explain, why "no trace" and "no reponse of frontplate"

It is funny , where got i   hybride and  desoldering of hybride is  painful job.

A useful scrap. (3 channel works )

Greetings
matt

[madao]

I got this unit with  TDS3GM-Modul. TDS3GM Modul was a main reason for acquire of scrap. I can sell it again and zero cost for me. Of coruse , i'll using him for MCONFIG-Hacking.


Scrap show life and all both input is good, frontplate MCU is not dead. 
Goood :-)!


Then: cracking of old hybride with screwdriver.



heavy desoldering job, huge mass and little solder joint,  JBC solder iron is at limit and i have drilling  solder joint with 1mm drill.



SPC running....


Successful !



HÄ....picture attachments function fails... whatever , no desire.

[max.wwwang]

Well done!

[sicco]

I’m in the same position: needed a TDS3GM or TDS3GV rs232 serial module for my tds3034, found an eBay ‘for parts’ tds3012 with TDS3GV, and now have a left over not fully working TDS3012.

I think I used the same eBay source as madao used, from Israel, they advertise with loads of 3012 and other modules, and these Tek tds3000 scopes all look as if they’ve experienced bomb explosions in war zones. Or died in some weird scientific experiment!

The fault in my tds3012 is very similar: front panel uPD78011 chip seems dead. My 10 MHz crystal runs though. But it is clear from the BNC probe interface pads that this front panel microcontroller is dead. ESD killed it I also guess.

However, and that’s why i post here, swapping out the front panel with the tds3034, does not get me a working scope back. The scope functions as a scope, but no response on any front panel key. Two green leds with the tds3034 panel, but no leds with the 3012 front panel. Question: does this confirm there’s more wrong on the main board of the tds3012? In other words: should a tds3034 front panel work on a tds3012 who’s panel failed?

Some of the near BNC active probe signal pads go directly into the main board via the purple wires. Huge ESD or a short in an active probe that gave use + or minus 15V on the TTL/CMOS pads (I2C ?) that killed not only the 78011 panel chip, but even more on the main board.

Anyone who has a spare working tds3012 keyboard front panel? / pcb only? Bad encoder also not a problem for me.
A circuit diagram?
Confirmation that other scope panels should work?

[madao]

It is possible, mainboard is damaged.  I have same case, here is hybride  dead.


I don't know 100% about communication between  frontplate and  mainboard.
I can tell:  serial communication (possible i2C) and  Reset line is there, include   4x voltage (+-15V and +-5V ) for tekprobe.

I have here a frontplate with dead mcu and broken encoder.  It is a ubotanium :-( I can tell: TDS3014 runs with  TDS3012B frontplate.
I have  TDS3012 corpse left, but it wouldn't help you.  This corspe have white plastic with extreme degradation of stabilty. I can press with finger and it breaks in more pieces.
Better: you give/sell  broken TDS3012 .   

Greetings
matt