Electronics > Repair

Agilent 34410A parts identification


Can anyone identify U800 that is located right behind red shroud of input terminals?  It is a 6 terminal device and mine becomes awfully hot.  (too hot to touch) 

Someone posted a nice photo of it here on another thread, so I'm going to repost it.  I hope he/she doesn't mind....  only marking I could read is "8K72".

Unlike it's cousins, service manual does not have any parts identification section or a circuit diagram.


34410a schematics  https://doc.xdevs.com/doc/HP_Agilent_Keysight/34410A/34410-66521_schematics.pdf
Page 2 of 14 shows U800 as a buck-converter generating 3.3V_FPGA and 3.3V_A. Agilent 1827-0634.
SMD marking 8K72 led me to a few Torex Semi parts like XC9258 but not a match. This is as far I can help.

The feedback voltage is 1.25V.

LM2736 looks suitable (wrong marking):


I would check whether the output is being overloaded.

More candidates (wrong marking):

https://www.micros.com.pl/mediaserver/info-st1933ltes6.pdf (LT1933)

http://www.farnell.com/datasheets/85166.pdf (LT1934)

Thanks both!  Greatly appreciated!


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