Lecroy Wavesurfer Xs CPU Upgrade - BCM MX855 BIOS   - Page 1
Forum section: electronics / testgear

author: Momchilo
author_rank: Regular Contributor
timestamp: February 11, 2021, 10:52:39 pm
content: Hi,I'm in the process of upgrading an old Lecroy Wavesurfer Xs scope with a better CPU instead of the Celeron M320.It's a BCM MX855LC mainboard with an Intel 855GME chipset with 400MHz FSB and the mPGA478C socket (manual of similar board.So I replaced the Celeron with a Pentium M765 SL7V3. But the PC isn't booting anymore. The fans spin, but no image or beep. I guess the BIOS version is too old and doesn't support Dothan CPUs. It's v1.02.The manufacturer has a list of legacy hardware and theoretically still offers the old software for it (http://www.bcmcom.com/bcm_support_driversAndBiosDownload.htm). But many links on the page no longer work and of course the one for the MX855. I couldn't find anything for the installed MX855LC. I guess it's the same BIOS firmware as for the MX855.It works flawlessly with the Celeron. I ordered also two different CPUs (Intel Pentium M 1.6GHz SL6FA and Intel Pentium M 735 SL7EP) just in case I bought a broken one or the Dothan series isn't supported at all (not arrived yet). I also asked the manufacturer BCM for the latest BIOS version for the motherboard.Does anyone have a newer BIOS version than v1.02 for the MX855LC mainboard or know how do you get the CPU running on this machine? It should be compatible.Thanks for your effortBest regardsMomchilo

author: Algoma
author_rank: Frequent Contributor
timestamp: February 12, 2021, 02:03:02 am
content: Here is a past thread, with a similar upgrade to the same Mainboard:https://www.eevblog.com/forum/testgear/teledyne-lecroy-wave-runner-(m)xi-upgrades-wrxi-wrmxi-series/Appears to be more related to memory and FSB timing. They upgraded to a Pentium M 780 @ 2.26Ghz .. even faster than that M765. I see a few on eBay.The mainboard manual from BCM mentions a clear cmos is required to reset the memory timings (not certain if this is an advisable step for this particular application), and that matching speed memory modules are required with the higher Bus Speed of the Pentium chip, for the system to boot, as noted in the BCM MX855 manual.I find a few similar active discussions on the subject in this group here:https://groups.io/g/LeCroyOwnersGroup

author: Momchilo
author_rank: Regular Contributor
timestamp: February 12, 2021, 11:00:34 pm
content: Thank you Algoma for the tips and links. Since both CP4Us have the same FSB frequency of 400MHz, there shouldn't be a conflict. I made a CMOS reset and tried different RAM modules. At the moment it's a 1GB 400MHz Kingston module that is recognized by the mainboard with the Celeron without any problems.But I tried every possible combination and it's still not bootingBut there aren't a lot of settings regarding timings and similar stuff. The BIOS is very simple.I just hope that the delivered 765 is faulty which I tried to get running. For every change in the BIOS I have to swap the CPUs, it's not that much fun.

author: darchons
author_rank: Newbie
timestamp: February 21, 2021, 02:42:40 am
content: Hi Momchilo,I am in the process of upgrading a 104MXi, and I have attached my BIOS, which appears slightly newer than yours (1.0.3A from October 2007).Would you be willing to upgrade your BIOS to this version, and let me know if it works with the 765 CPU? I think you can use this flash tool,https://www.wimsbios.com/files/flashers/awardwinflash/awardwinflash194.zipThanks!

author: spicytofu
author_rank: Contributor
timestamp: October 01, 2022, 08:19:35 pm
content: Digging up old thread to add to this.The BIOS file posted above works using the WinFlash utility. You need to disable the BIOS write protection in the BIOS first. I was able to flash my v1.00 dated 2005 to the version posted above dated 2007. I have a 104Xi, but the motherboard looks like the same MX855 variant. My next goal is to add 1 GB of DDR1 PC3200 RAM and get the fastest Dothan core I can find for a reasonable price.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 02, 2022, 02:18:47 am
content: An user manual ??

author: spicytofu
author_rank: Contributor
timestamp: October 05, 2022, 10:35:58 pm
content: Quote from: darchons on February 21, 2021, 02:42:40 amDon't know if you are still looking for an answer, but the 533 MHz FSB Dothans do not work using your 1.03a BIOS. There is no way to find out what was the last BIOS version and CPU support. Hope someone can give us a dump. I placed an order for a 400 MHz FSB Dothan.

author: RamboChen
author_rank: Newbie
timestamp: October 24, 2023, 02:53:44 am
content: Hi spicytofuHave you finally verified that a 400 MHz FSB Dothan can work correctly on 104MXi？