I haven't tested this fully, but think it works and leave it to you to play with it.
You can manually add filter parameters to the search URL even when those options are not available on th left hand filter nav menu. Note that adding some of these will produce odd results on the left nav menu and in the filter list above the search that you pretty much have to ignore. (for example, adding "parts or not working" filter via URL parameter in a search where that filter isn't an option on left nav produces a "used" filter indication or a second one if "used" was also specified on left nav and in filter list, etc)
Control the search by modifying the URL and/or removing filters via the X "close" options above the search.
Example fixed up URL:
_sop=1 is ending soonest filter LH_Prefloc=1 is US Only
The LH_ItemCondition parameter is the one we are interested in. In the URL above, ALL the possible condition filters are chained together ( with | ) but with the "Parts or Not Working" option not included. That does what you want - everything but "Parts or Not Working"
To see only "Parts or not working" when that filter option isn't present something like this would work:
Here are the Condition values I hunted down (there may be others):
LH_ItemCondition ---------------------------- 10 Not Specified 1000 New 1500 New Other 2000 Manufacture Refurbished 2500 Seller Refurbished 3000 Used 7000 For Parts or Not Working
Here are some other search URL parameters that can be used to force search to do what you want (bookmarked searches can be constructed with them to "seed" searches with particular properties even if eBay GUI won't let you, or bookmarklets can be created, or Redirector filter rules can be constructed)
eBay Search URL parameters In search page URLs: View (top right next to Sort) ------------------------------- _dmd=2 gallery view _dmd=1 list view _dmd=0 list view not present list view Item Location (left navbar) ------------------------------ LH_PrefLoc=0 default LH_PrefLoc=1 US Only LH_PrefLoc=2 Worldwide PrefLoc=0 default PrefLoc=1 US Only PrefLoc=2 Worldwide _sadis=15 Within search distance _stpos=95825 Within reference zipcode Include description (top under searchbar) --------------------------------------------- LH_TitleDesc=0 don't include LH_TitleDesc=1 include Price (left navbar) --------------------- _udlo=20 _udhi=50 Items per page ------------------------ _ipg=10,50,100,200 Sort: (top right) ------------------------ _sop=1 Time: Ending soonest _sop=7 Distance: Nearest First _sop=10 Time: Newly listed _sop=12 Best Match _sop=13 Ended Recently _sop=15 Price+Shipping: lowest first _sop=16 Price+Shipping: highest first _sofindtype=nn ------------------------------ 25 = by seller 2 = by seller &_fcm=1 for close matches? 3 = by bidder 9 = contact info 5 = LH_ItemCondition ---------------------------- 10 Not Specified 1000 New 1500 New Other 2000 Manufacture Refurbished 2500 Seller Refurbished 3000 Used 7000 For Parts or Not Working --------------------------------------- If "Sold Listings" and "Complete Listings" checkboxes are grayed out probably
because "Include Description" box is checked.
This could all be implemented with a GreaseMonkey script that could provide all the Condition (or even other) options on the left nav menu all the time, and even fix up the bogus and duplicated left nav indicators and filter list indicators that result from the forced filters, but it's WAY too much work and addresses a moving target. (I'm not doing it, but anyone else is welcome to have at it.) I'll stick to customized bookmarks and simple bookmarklets for my uses.
If this doesn't address the problem then never mind 
