Products > Test Equipment
Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
analogRF:
that crappy motherboard costs a lot of money these days so i doubt he will want to buy a motherboard for it...when it didnt boot, he was going to sell it as is, i convinced him that i can repair it and it must be a piece of cake and here we are :palm: :-BROKE
My gut tells me it must be a very simple thing that I am overlooking... |O
if push comes to shove, I am going to program a new BIOS chip with one of the BIOS files on the FIC ftp server and see what happens
anybody knows what is the BIOS EPROM model? it has a sticker on it I dont wanna remove for now...
AJ3G:
I forget where, but I thought there was some online documentation suggesting that other boards may be used, but the chassis would have to be modified (i.e. drill new holes). Yes, I agree buying the same motherboard would be expensive, but using an alternate would not, provided you were willing to make some modifications to the sub chassis.
I do not know the BIOS EPROM Model off the top of my head. Later today I can take a look if you like.
nctnico:
Let's do a recap:
- Original problem is that it is stuck at 'verifying DMI pool data' and this didn't change. So nothing you did made the problem better or worse.
- Getting stuck at this point hints towards a BIOS / boot problem problem but it could be anything.
- All the contacts have been cleaned (I assume including the configuration jumpers) so let's rule out a contact problem.
Perhaps you need to replace more capacitors. I assume you have used low-ESR types from a reputable source to do the replacements earlier.
analogRF:
yes, your recap is spot on. Configuration is done by microswitches which I sprayed IPO and switched them several times (even number of times!) and yes made sure they are exactly where they were before and match the 54845 service manual , so are the BIOS settings
I have replaced all 1000uF and 220uF caps (all with high quality brand new Nichicon and Panasonic) those were the bulging caps and most of them part of dc-dc converters
then there are like 20-25 tiny 10uF bypass caps all over the place which I randomly chose 2-3 of them and replaced
but taking the caps out of this multilayer board is really a nightmare. 10uFs were not that bad although not as good as the new ones i installed
maybe there are a few of them somewhere that are really bad? but they dont seem to be that huge of a deal that can cause such problem
i can try to replace more of them if you guys really think that could help
nctnico:
Did you use hot-air during removal and fitting of the capacitors? In my experience this is the only way to get a capacitor replaced on a PC motherboard.
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