Author Topic: 34970a bootloop  (Read 272 times)

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Offline f14

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34970a bootloop
« on: October 18, 2020, 11:06:50 am »
Hi Guys,
After fix the error code 625 by replace MCU 89s52 with fw from other 34970s . I get new problem. my 34970a keep restart over and over (bootloop) when I install the 34902a card ( this card working good in other 34970a ). 3 slot have same issue .
but when power on without card it can boot up and pass the self test without any error code
have any idea?
thank you
 

Online alm

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Re: 34970a bootloop
« Reply #1 on: October 18, 2020, 04:19:59 pm »
Did you check for ripple the power rails, especially with a card installed? I'm thinking it might be dried electrolytics. The increased current draw by the card might cause the ripple to increase.
 
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Offline f14

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Re: 34970a bootloop
« Reply #2 on: October 18, 2020, 04:38:44 pm »
 I'm checked all supply voltage from P302 connector . and seem very normal with/without card (double check with other 34970a). after that I'm try to replace two 2200uf 35v by one 4700uf 35v but nothing happens :palm:
maybe problem come frome reset signal from u305 or u304?.
 

Offline f14

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Re: 34970a bootloop
« Reply #3 on: October 19, 2020, 12:58:38 am »
try to replace again 2200uf 35v by 2200uf 25v( i dont have 35v caps) and u304 with new ACT14 . it back to live  :-+
//I'm attach a rom of U305 . for someone else need it to fix error code 625.
« Last Edit: October 19, 2020, 01:06:06 am by f14 »
 
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Online alm

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Re: 34970a bootloop
« Reply #4 on: October 19, 2020, 08:46:01 am »
Thanks for posting the solution, and congratulations on the fix!
 
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Offline f14

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Re: 34970a bootloop
« Reply #5 on: October 19, 2020, 12:44:10 pm »
yeah. this will help someone get error code 625 but gpib controller TMS99C14FN still working :scared:
small notice. this rom I attach for U305 . can work with old 34970a use 87c521  and newer use 89s52 . you can write it without problem . maybe it can work with other agilent equipment with same error 625 :popcorn:
 
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