BIOS selection switch absent on EVGA Classified SR-2; assistance needed with jumper connections.
BIOS selection switch absent on EVGA Classified SR-2; assistance needed with jumper connections.
Hey there! Thanks for sharing your progress. This EVGA Classified SR-2 has been through a few changes—some parts were taken off for an electronics project, which explains the missing capacitors. It looks like the BIOS selection switch is gone too, and I haven’t found a replacement anywhere. If you can locate a new part, that would be great. Otherwise, you might need to rewire jumpers or even swap in a different switch. Let me know what you think!
Remove the selection switch entirely; identifying the connector requires seeing the exact footprint and wiring. Check the part number on the BIOS chips, as they are marked with orange dots and the chip above them. Locate the datasheet using that number and determine which pin serves as ENABLE or SELECT, likely the one controlled by the switch. The switch probably links a trace to one of the three enable/select pins on the chips. Use a multimeter in continuity mode to test each connection. Connect one probe to a pad or hole of the switch and another to the enable pin of the chip; if it beeps, you’ve identified the correct lead. Once the footprint is confirmed, you can find matching 3-position slide switches at distributors, choosing models with the right spacing (rows or individual pins). For instance, here are 120 available switches (540 in stock) categorized by type: SP3T or DP3T as shown. It’s crucial to identify the footprint before selecting the correct version. You can then filter by surface mount or through-hole options, and search for models with proper pin arrangement. The part number or manufacturer details may appear on the packaging or under a protective cover, which often conceals the actual switch design. If you understand how the switch functions, you might solder a wire across two pins to activate a specific BIOS chip.
It appears there are only three pins connecting that switch to the motherboard. I reviewed the board and found no modifications—definitely won’t boot without the BIOS switch. The remaining part is just empty space or what’s left after someone removed it. Warning: The white section isn’t the actual switch; it’s debris from the removal. It might be just a support pad for the real switch. I couldn’t locate anything comparable on the digikey link you provided, unfortunately.
If there are only three pins, it indicates the switch changes between just two BIOS chips. Such switches aren’t available in the link you received since it’s configured to show only devices with three positions. Typically, a setup like this would look like this: [1] to BIOS 1 → [2] from chipset → [3] to BIOS 2. There are 209 SPDT switches (single pole, double throw/tap, etc.) available on Digikey: https://www.digikey.com/short/zr0zz7tj. They don’t have to be identical, as long as the pin spacing and pin thickness meet requirements.
I purchased my SPDT from Amazon, expecting it to function properly. The problem is that the board didn’t change its behavior even after re-capping everything... It seems like this motherboard isn’t working well. I bought two extra x5650s just to test, but honestly, there’s no real chance of fixing this setup.
And it's fairly OBVIOUS, but ideally you would get a programmer and actually CHECK the bios chips to see if they have content written in them. AND, also check the bios inside the bios chip holder... if there even is a bios chip in the bios holder. As that's an overclocking motherboard, one bios may be simply erased, or one of the bios may have presets and everything set for LN2 overclocking or some other ridiculous settings, which would cause the board to simply not start. A programmer is as low as 3-5$ .. see for example CH341 and volt mod it to 3.3v or whatever the flash chips need.... see video below. And I've explained to use a multimeter to test traces and figure out how that switch works ... either you don't have a multimeter OR you don't know how to use it OR you're lazy OR you can't be bothered to follow tips and instructions ... just say so then, so me and others won't waste our time trying to help. And last but not least... I think I've asked for you to post some clear pictures of the board... you have the motherboard, is it too hard to grab your phone or some camera and take some clear pictures? There may be some other parts missing or broken that you're not seeing. Other pairs of eyes may be able to tell you what else is bad. The board was obviously hit on the bottom edge, I can see the bent header for programming the bios chips.... which by the way ... if you had bothered to read the manual, it would tell you what each pin of that header does, so you could use the multimeter from that header to the bios switch to figure out the traces.
Look, I'm doing this in my free time, around 30 minutes a day. No need to be so mad, and additionally I already checked nearly everything. 1. Cleared CMOS, chances are the BIOS has no settings on it. 2. Don't expect me to buy things I don't have to fix it, that I won't use in the future. I got the spare cpus and coolers because I need them on other projects anyways, like finishing my multiple r710 blade server rack. 3. There's a reason why I found an SPDT switch before you even mentioned it? I already tested the enable pin. Which is why I have high hopes for that damn switch. 4. There's no missing parts other than the caps which I already replaced, and the bios switch. (Speaker doesn't count since it doesn't matter for post.) 5. THERE ISNT ANY INFORMATION about the bios header, holy crap. I believe what you mean is the EVGA Control Panel tester, which does nothing related. Please go read the manual yourself, I've read it at least 30 times by now. I'll even be nice and link it here for you: https://www.evga.com/support/manuals/fil...S-W555.pdf 6. There is a bios chip in the holder, which seems to be in perfectly good condition. I'm just waiting for the switch to arrive.
Excited to show you were mistaken. It turns out a few connections are faulty—expected when parts are cut off—and one unit isn’t working. Disappointing. Still unsure which readings to check next.