Hello masters..

this board came water damaged, DA0X8JMB8E0 Rev E with discrete graphics,
cleaned and restored except those two chips:

#1 marked "ZU8KA" and #2 marked "AE"


Location on DA0X8JMB8E0 DSC


#2 was easy to identify, a simple 2-input AND gate, it is a 74AHC1G08GW - datasheet


No schematics / boardview of Quanta X8J was found to identify chip #1 but identical chips was found in a different location on photos of DA0X8JMB16E0 "UMA", sadly no schematics / boardview too:


accidentally i've found that this part of the board (DA0X8JMB16E0) is identical to the design of Quanta X8M (DA0X8MMB6D0) and the boardview is available:


so we have the pinout of those chips now

by studying the design and matching to the schematics of Quanta X81 i can confirm now that chip #1 (ZU***) = MC74VHC1G08DFT2G - datasheet

BUT!!! according to the schematics chip #2 is also MC74VHC1G08DFT2G ?! which is a simple 2-input AND gate too..
note that both are supplied by +3v


went back to Quanta X8M's boardview and found that the difference is that MC74VHC1G08DFT2G (ZU***) is supplied by +5v while 74AHC1G08GW (AE) is supplied by +3v, but according to the datasheets both chips can handle 5v supply and i didn't find any differences so i'm lost at this point

what's the difference between those two, or did i identify them incorrectly ??

another scan x8j-6l - zu*** = vt. mc74vhc1g08.

>> Location on DA0X8JMB8E0 DSC >>>>>

I can’t see from the photo which body it is. sot23-5 or less.

this photo is from DA0X8JMB16E0 UMA, in the discrete board 8E0 the location is different..

it helped a lot :-ok-:

in your photo ZU*** = VT & AE = V2

by studying the datasheets everything become clear:

ZU*** = VT = CE = 74AHCT1G08 = MC74VHC1GT08 <- TTL Compatible Input

AE = V2 = 74AHC1G08GW = MC74VHC1G08 <- non-TTL

so they are not interchangeable :co_ol:


SOT-353

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Posted after 4 hours 50 minutes 32 seconds:
MC74VHC1G08DFT2G found and installed

74AHCT1G08 found in SOT23-5 package (74AHCT1G08DBVR) and installed

board started perfectly :co_ol:

input supply voltages measured on this platform (DA0X8JMB8E0 Rev E DSC):

MC74VHC1G08DFT2G pin#5 = 5v

MC74VHC1GT08DFT2G pin#5 = pre-init 1.2v , after-init 1.35v

thx :-ok-: