Author Topic: Tektronix TDS580D A10 acquisition board MM9599 UCC (Solved)  (Read 1737 times)

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Offline pmax65Topic starter

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Tektronix TDS580D A10 acquisition board MM9599 UCC (Solved)
« on: January 12, 2017, 11:05:12 am »
Hi there, I experienced a failure on my TDS580D DSO.
The error logger reports the DAC2 Varigain DAC too high, and indeed the CH2 hybrid attenuator/preamplifier variable gain input is set to its maximum, and its output correctly is about 40% higher than what it should be.
I checked the CH2 attenuator/preamplifier anyways swapping it with CH3 and nothing changed, confirming that the attenuator/preamplifier is good.
Since the circuitry after the attenuator/preamplifier output is changed from the TDS520B schematics available on the Internet, I would like to know if someone out of here had any information about that circuitry.
In particular, I would like to know what is the name of the integrated circuit which seems to embed the sampling triggers logic and maybe the 4 ADCs which has the heatsink sticked on it.
I also would appreciate any information about the National semiconductor’s BGAs named MM9599-UCC.

Have a great day.

Massimo
« Last Edit: January 14, 2017, 03:24:13 pm by pmax65 »
 

Offline PartialDischarge

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Re: Tektronix TDS580D A10 acquisition board MM9599 UCC
« Reply #1 on: January 12, 2017, 11:20:24 am »
IIRC in my TDS744 those chips (trigger logic, and ADCs) are custom made parts and pretty much every big IC you see in that board is.
 

Offline pmax65Topic starter

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Re: Tektronix TDS580D A10 acquisition board MM9599 UCC
« Reply #2 on: January 12, 2017, 01:28:21 pm »
I there,
thank you for your interest in this issue.
Yes, I know that, I just looking for any info (such as pinouts) about those chips for planning a diagnostic strategy of the signals between them.

Have a great 2017

Massimo
 

Offline pmax65Topic starter

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Re: Tektronix TDS580D A10 acquisition board MM9599 UCC (Solved)
« Reply #3 on: January 14, 2017, 03:33:21 pm »
Hi there,
I finally fixed the DSO.

It was a silly TL074 named U702 placed close to the hot IC U700, which it look like it has embedded the trigger logic, the sample & hold circuitry and the 4 ADCs that until version C were split in 5 different ICs.

In few words U702 in the D series DSO does the work of U701 detailed in pages 9 to 12 of the schematic included into the file "TDS520B_Digitizing_Oscilloscope_Component_Manual.pdf".

The output driving the ADC channel 2 reference input had the output stuck to 4V.

Have a great day and an happy 2017.

Massimo
 


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