EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: wukiduki on June 10, 2018, 03:35:31 pm
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hello!
Recently got a tds754d oscilloscope, the function looks normal, but the processor self-test cannot pass.
I have cleaned the PCB, the problem still exists.
Does anyone know which chip is related to this error?
Need some help. :-BROKE
ERROR Log read via gpib:
THU JUN 07 13:06:34 2018 ERROR: diagnostic test failure, dsp68kInMemTest,
** addr = 0x7028200 exp data = 0x55555500 actual = 0xff555500,
** addr = 0x7028204 exp data = 0x55555500 actual = 0xff555500,
** addr = 0x7028208 exp data = 0x55555500 actual = 0xff555500,
** addr = 0x702820c exp data = 0x55555500 actual = 0xff555500,
** addr = 0x7028210 exp data = 0x55555500 actual = 0xff555500,
** addr = 0x7028214 exp data = 0x55555500 actual = 0xff555500,
** addr = 0x7028218 exp data = 0x55555500 actual = 0xff555500
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It could be a bad assumption, but since all the addresses tested get the same bit pattern wrong, I might suspect some memory address PCB traces could be corroded? I know that was a problem of many of these scopes. Electrolytic capacitors leaking and the following corrosion on the board itself.
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Old questition, i know, but it may be helpful for other people with search word "dsp68kInMemTest"
But, i want tell about this ERROR.
I got a TDS754C from israelite surplus shop.
This unit has same fail.
cpuDiagDsyAccess ............... pass
dsp68kMemTest .................. ***FAIL***
..error details:
ERRORID: 162 diagnostic test failure dsp68kInMemTest
** addr = 0x7000000 exp data = 0x7fffff00 actual = 0x7f5fff00
[attach=1]
Reason: one of three bad SRAM for Tristar DSP
U870(middle below ), U871(middle upper, this is bad), U872 (upper).
Greetings
Matt
BTW: dsp68kD1MemTest = bad U1008 or U1009.
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I got a 784A that did a similar thing and everyone was saying that it was one of the memory chips but I located it to some dry solder joints on one of the big arse QFP chips on the main acquisition board. Use a fine dentist tool and carefully pull on each leg of the QFP and see if it is firmly soldered to its pad.