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Need to find a repairing guide of Radisys LS855 motherboard

PostPosted: Mon Mar 07, 2016 12:07 pm
by isend
Our Agilent vector network analyzer (bought in 2011 brand new) uses a Radisys LS855 motherboard. This motherboard died after a brownout last month, and Keysight asked for 9,000 USD for repair after diagnosing the analyzer because LS855 has been discontinued. (9,000 USD is for upgrading the motherboard and all the other modules connected to it.)

We cannot afford the money. I tried to request a circuit diagram or a repairing guide of LS855 or of a similar model from Radisys, but Radisys does not respond. What else can I try? (Our technician has some knowledge about motherboards, but it's much more difficult to try fixing it without a test/repair guide.)

Thank you.

Re: Need to find a repairing guide of Radisys LS855 motherbo

PostPosted: Mon Mar 07, 2016 4:05 pm
by Karlsweldt
Quite an exorbitant amount for repairs! But depends on how much damage was done, and if original parts can still be gotten.
But as to the motherboard, is there a reason another type that has the same specs and performance cannot be used?
Did find a link for an Intel BLKMGM45RM E24789 Mobile Board that is socket 479, new.
May be a manual at this link.. https://www.agilent.com/en-us/library/usermanuals?N=135

Re: Need to find a repairing guide of Radisys LS855 motherbo

PostPosted: Mon Mar 07, 2016 10:48 pm
by isend
To Karlsweldt,

Thank you. According to the Keysight report, the only part which is damaged is the motherboard. The reason to upgrade the other parts all together is for compatibility. Keysight technicians are asked (by the company) only to replace parts, not to repair them.

So we want to try to repair the motherboard ourselves in order save money. We do need a detailed test guide or a repair guide of this motherboard. (It's possible Keysight has a test guide, but I avoid asking them for now, since their philosophy it *not* to repair the parts.

Re: Need to find a repairing guide of Radisys LS855 motherbo

PostPosted: Tue Mar 08, 2016 6:13 am
by Karlsweldt
Motherboard repair is a limited field. Most components are not replaceable, unless special tools are used to desolder chipsets without damage to traces or nearby components. The only components of a motherboard that are somewhat easy to replace are the capacitors. Replacements must be of the same exact value and voltage as the original, graded as low-ESR, and 105°C. temperature range.
Look over all the capacitors on that board. If any show excess lean, domed tops or signs of leakage, they are bad.
There was a plague of 'bad capacitors' that affected the entire electronics field. More info at www.badcaps.net/
There is a 50/50 chance that if bad ones are replaced, the board is still usable.
An exact replacement motherboard may be found, maybe not. If a substitute is found with identical specs and features, good chance the device should work again. But depending on the OS type and version, a possibility of it going belly-up if major differences are found between the old board and the new.

Re: Need to find a repairing guide of Radisys LS855 motherbo

PostPosted: Tue Mar 08, 2016 11:42 am
by Mr T
Check this out.. Also look on ebay, there are some 'equivalents' out there...

First thing I would check is the power source to the motherboard, and test it by removing the board from the case and powering up (or attempting) to power it up on a 'bench'.. Also if you can get known working parts and test the CPU and RAM - just because a system is failing, doesn't always point to a motherboard. For a company to quote $10k for an upgrade, if you don't need one, you have to question motives or get a better service level agreement..