Tektronix DPO70804 Oscilloscope and Acquisition Error Code 321

[bracecomputerlab]

First time poster here on eevblog.com forum.
I recently purchased Tektronix DPO70804 8 GHz bandwidth oscilloscope.
Unfortunately, the seller did not disclose that the unit suffered from acquisition error code 321 (PaDma) when I run the oscilloscope's diagnostics test.
I specifically asked about this specific potential issue prior to the purchase since another seller of a similar model (a broken Tektronix DSA72004B that the seller disclosed the acquisition error code 321 issue and selling it as-is / no return for about $12K) had such an issue.
It appears that this is a fairly common failure mode of Tektronix DPO70000 / DSA70000 family.
The seller did not really respond to the question, and commented on its cosmetic condition, etc.
Unfortunately, I did not know any better, and discovered the issue when I ran the diagnostics myself.
I spoke with an oscilloscope repair shop nearby that has experience fixing Tektronix DPO70000 / DSA70000 family, and they told me that I will likely pay something like several times of the not so significant purchase I paid for.
This person I spoke with suggested that this is a known issue, and I should return to the seller due to its high repair cost.
Someone on this forum talked about reviving his / her Tektronix DPO70604 a year ago suggested a heat related BGA package issue might be the reason why a Tektronix DPO70000 / DSA70000 fails over time.
At this point, I plan to return the unit for a full refund (maybe minus the shipping cost), but how much does it cost to resolder affected BGA packages on that huge analog acquisition board that contains exotic IBM SiGe amplifiers?
I appreciate any advice or suggestions.

[coromonadalix]

return it  period

reballing bga   if not equipped ...  you will need  to heat the board,  kapton tape to protect surrounding parts,   have hot air equipment(s),   bga stencils,  solder paste for reballing   etc .... anti static garnments

[bracecomputerlab]

return it  period

reballing bga   if not equipped ...  you will need  to heat the board,  kapton tape to protect surrounding parts,   have hot air equipment(s),   bga stencils,  solder paste for reballing   etc .... anti static garnments

You are the third person so far that thinks I should return the item, and it is really 3 / 3.
Thank you for the advice.

[calibrationfixture]

Hi bracecomputerlab,

Found this on the internet, maybe your Unit:

" Tektronix DPO 70804 Digital Phosphor Oscilloscope, 8GHz, 25GS/s , 100-240V, 50/60Hz, w/ opt STU JA3; 4ea TCA-292MM adapters. Serial no. B020586. (fails SPC and diag 321, scope fails BWE at 8GHz all channels) "

I don't know the amounts involved. Even without a good Acquisition Board, when such a Scope Powers Up etc. it has some considerable value.

The Acquisition Boards of these Scopes are very thick, making a succesfull Rework difficult and if successfull for how long it will sustain. A perfect fit with the Board is Key in getting rid of the heat on the Die. Heatsinked or not. Read recently some AMD Comments on CPLD Reworks.

Calibrationfixture 

[bracecomputerlab]

Hi bracecomputerlab,

Found this on the internet, maybe your Unit:

" Tektronix DPO 70804 Digital Phosphor Oscilloscope, 8GHz, 25GS/s , 100-240V, 50/60Hz, w/ opt STU JA3; 4ea TCA-292MM adapters. Serial no. B020586. (fails SPC and diag 321, scope fails BWE at 8GHz all channels) "

I don't know the amounts involved. Even without a good Acquisition Board, when such a Scope Powers Up etc. it has some considerable value.

The Acquisition Boards of these Scopes are very thick, making a succesfull Rework difficult and if successfull for how long it will sustain. A perfect fit with the Board is Key in getting rid of the heat on the Die. Heatsinked or not. Read recently some AMD Comments on CPLD Reworks.

Calibrationfixture

Hi Calibrationfixture,

No, the S/N of the unit I have is, B031XXX.
Because I still have not contacted the seller, so I do not think I should disclose the full S/N.
Speaking of the S/N, by any chance, can Tektronix ever sell more than a few thousand of DPO / DSA70000 in its lifetime?
Because each unit costs over $100K in Year 2007 / 2008 dollars, I will assume that there are only a low thousands of DPO / DSA70000 in circulation around the world.
    When I purchased it, I was not fully aware of the need for a 5-15P to IEC C15 power cord to power the oscilloscope.
The seller did note the IEC C15's "notch" thing, but I did not hear about the IEC C15 plug specifically.
The unit is rated for 1,100 VA (basically a midrange microwave oven), and I did not have a power IEC C15 type handy, so I had to go buy one on eBay.
I purchased a what seems like a new old stock (unused, but was produced 15+ years ago type of an item) Tripp Lite right angle C15 to 5-15P, 125 V 15 A, 8 ft (Model: P019-008-C15RA), but purchasing it slowed me down by 5 or so days.
The power cable is 14 AWG, and I will never want to use anything less than that with DPO70804.
Almost all PC desktop power supplies connect to an IEC C13 power cord, but C15 power cord has part of the bottom portion removed.
This is apparently how Tektronix prevents 18 AWG IEC C13 from hooking up to the unit, and risk causing a fire incident.
I still have more than a week to arrange a return and I plan to contact the seller tomorrow (Monday).

[coromonadalix]

ah IEC C15    i had this in computer server stuff,  stupid  company did not put any in the box ??

but the plug was 15 amp max rated  but the equipment consumed 6 amps

while waiting for an original one, i notched with a dremel  an standard IEC to do my tests ...


As  for the scope, sure it may have  considerable value,  but the Op / buyer may or don't  want to mess and pay $$$$ to repair it, and get it certified

for me i would not ...  it depends of the needed resources to do so, or by luck   having salvaged parts from another ...

sometime  we get lucky, sometimes not ... that's why now i ask for tests screens shots  errors displayed etc ...

Thoses dpo's are easily  in the 30K $$$ used and Cal'ed, it's a huge risk  even for the good ones out of warranty

[calibrationfixture]

Hi bracecomputerlab,

When you decide to send the Scope back the notched Power Cord is not a waste. You need it also for the TLA7016's (your other Posting), assuming these are Standard (Early Model) ones. Many TLA7016's are "modified" TLA720/TLA721's. Later TLA7016's (B020000>) use a higher rated Power Supply with again another Mains Cord 

Calibrationfixture

[bracecomputerlab]

ah IEC C15    i had this in computer server stuff,  stupid  company did not put any in the box ??

but the plug was 15 amp max rated  but the equipment consumed 6 amps

while waiting for an original one, i notched with a dremel  an standard IEC to do my tests ...


As  for the scope, sure it may have  considerable value,  but the Op / buyer may or don't  want to mess and pay $$$$ to repair it, and get it certified

for me i would not ...  it depends of the needed resources to do so, or by luck   having salvaged parts from another ...

sometime  we get lucky, sometimes not ... that's why now i ask for tests screens shots  errors displayed etc ...

Thoses dpo's are easily  in the 30K $$$ used and Cal'ed, it's a huge risk  even for the good ones out of warranty

Hi coromonadalix,

No, the individual who sold me the scope did not include a power cord with an IEC C15 plug.
He did let me know of the odd plug socket in an illustration he sent to me, but did not seem to know the official name for it.
I had to research it to figure out this rather rare type of a plug.
Even someone like myself who has dealt with electrical equipment for years, did not know about it.
I guess I never really dealt with high power consumption industrial grade equipment.
I now see why microwave ovens come with a non-detachable power cord.
    You are right that, from now on, I will always ask for screenshots of passing self-diagnostic tests before even considering my buying a scope.
That's the biggest lesson I learned from this episode.
I hope it will help someone in the future that might catch bug that makes an individual have the urge to own an at or over 8 GHz bandwidth high-end oscilloscope on their funds.
That was me, and it will likely take me several years at a minimum for me to recover (recover = wanting to own an at or over 8 GHz bandwidth high-end oscilloscope, again) from this episode.
In the meantime, I will play around with my newly acquired and much more reasonably priced Tektronix TLA7012, TLA7016, TLA7AA4, and TLA7S16.
    I almost forgot to mention that I sent back the defective Tektronix DPO70804 oscilloscope yesterday (Friday) afternoon at the seller's expense.
This is because the seller selected this option when he listed the item on eBay.
I will likely get my money back, maybe except the ground shipping from the seller to me.
I had to waste a lot of my own time for dealing with this broken oscilloscope, but at least I will not get stuck with it.
Thank you for your advice on how to deal with this scope.

[bracecomputerlab]

Hi bracecomputerlab,

When you decide to send the Scope back the notched Power Cord is not a waste. You need it also for the TLA7016's (your other Posting), assuming these are Standard (Early Model) ones. Many TLA7016's are "modified" TLA720/TLA721's. Later TLA7016's (B020000>) use a higher rated Power Supply with again another Mains Cord 

Calibrationfixture

Hi Calibrationfixture,

I just got the delivery of TLA7016 at my door.
I was left there while I was inside my place.
I did not notice that it was sitting there for an hour or so.
I honestly do not anybody sane will try to steal it since the delivery box from a vendor located in Texas is even a larger (longer in one direction or rectangular) box than the box the broken DPO70804 came in, and is very heavy (easily over 40 pounds).
I finally sent the broken oscilloscope back at seller's expense.
I am glad he listed the item with 30 day return and seller will pay the return shipping options.
I will now go unpack my TLA7016 and place it next to my TLA7012.
I will take a look at the power plug to see which type it has.
Yes, I still have the right angled C15 plug power cord, and ordered three more from a different vendor on eBay (8 ft, 14 AWG, 5-15P to IEC C15).