I just wanted to let you know that I answered several ends of my problem.
My original problem was toofold; standoffs lost and screws worn and stripped, and the mother board bowing over the bracket securin my new CPU cooler to the mother board. It was formerly attached with plastic fasteners and they had weakened, requiring regplacment with something that can actually be trusted not ot come loose and cook the CPU.
I looked into just buying a new case. Store manager said he'd never heard of this problem.
I took the thing apart to take the standoffs in with me to deal with it. First thing I noticed, when I measured them, is they aren't no 6.5 mm or 1/4 inch.
Here is the ATX standard for motherboard standoffs, in effect since Version 2.1 in June of 2002. My Antec Sonata II was manufactured in 2006, according to the date in the case.
Version 2.1 of the ATX specification states that the length of standoffs needs to be at least 0.25 inches (6.4 mm), with their cross sections fitting within 0.40 by 0.40 inches (10 mm × 10 mm) square areas centered around each mounting hole on ATX motherboards.
ATX Specification Version 2.1 June 2002.
3.4.2 Secondary (Bottom/Solder) Side Height Constraints
Required secondary (bottom) side motherboard height constraints for all areas (A-C, as shown in Figure 7)
are defined as follows (measured from the bottom planar surface of the motherboard PCB):
• ≤0.010” – Mounting hole standoff areas – no components. Restriction applies within 0.400” square
area centered on each required mounting hole location defined in Section 3.2. Nominal allowance is
provided only to accommodate slight reflow solder excess.
• ≤0.098” – All board circuit components (including leads) that are electrically conductive and intolerant
of direct connection to chassis ground (e.g., through-hole leads, surface mount resistors)
• ≤0.120” – Board components that are non-conductive or otherwise tolerant of direct connection to
chassis ground (e.g., connector guide/stake pins)
• ≤0.200” – Devices attached to the motherboard for the sole purpose of structural retention or stiffening
A chassis and its related elements (e.g., stiffening ribs, base pan, structural supports fasteners, etc.) must
allow ≥ 0.250” clearance to the bottom planar surface of the motherboard PCB. This does not including
mounting hole standoffs, which may extend to and contact the PCB at the mounting holes within the
prescribed 0.400”-square areas.
The standoffs I took out of my case, which are the ones that came with the case, are 5.5 mm. The clearance my CPU bracket needs measures at exactly 6.5 mm - the minimum standard.
Antec sold me a case with standoffs that don't meet the ATX standard.
This is why they won't tell anyone what the specifications are of their standoffs!
It's also too consistent with their poor customer service.
Anyone stating that Antec has good customer service is also probably insisting that Ben Carson is "a very softspoken man", on which topic don't even get me started. It's a true wonder in how today's upper middle class brain works; I now feel like I understand the ever so well mannered upper middle class people who say and write these wonders, and I've been waiting half a lifetime to achieve that.
When shopping for cases, I noticed that, rather than being distinguished by quality, the Antec cases are ACTUALLY distinguished by low price. My guess is they are made in China and don't meet any actual specifications. The buyer just gets whatever he or she happens to get.
For the next person who wants to know what the standoff specs are, I don't fully have the answer, but Frys sells only two replacement standoffs in store. There is Computer Screw Kt by Link Depot, storage box included, and some other ones that looked identical as far as size and thread. Both screwed into the case. The ones in the computer screw kit also fit the screws provided. Both are described as #4-40.
My guess is they're the 6/32 that most standoffs are, and they measure at 6.5 mm or 1/4 inch. The kit contained four sets of screws, one of which was M3. Exactly one set of screws fit the OTHER set of standoffs, so those must take M3 screws. Probably the ones in the kit take 6/32 screws, but then again, it might be "#4-40" screws.
The idiot from Antec told me that all Antec cases use the same standoffs. For whatever what the idiot told me is worth. On Antec's web site they sell two sets of screws and standoffs for two specific cases, and neither has the same price as the kit he quoted me a price for, which is said not to be listed on the site.
I have the replacements in my case now; bowing gone, and the 1 mm difference hasn't prevented me from being able to plug my dual monitor setup plugs into the video card.
Edited by villandra, 14 November 2015 - 05:15 PM.