If I recall correctly those drop targets use a separate set of contacts to register when all three are down. That would explain why they register individually but not as a set. Double check the wiring and the diodes on the drop target to be sure there are no obvious breaks. When all three targets are down, wiggle them a bit by hand. Mine had the same problem but when I'd wiggle the targets themselves they'd pop up, indicating the switch contacts were not making a good connection. I assume you've tested all the other switches in the machine and they all work properly?

I had a problem like that with one drop target bank. I took the bank from the playfield and disassembled it. There are horseshoe shaped contacts on each droptarget, with 3 contact areas, the look like drops of copper, see if all 3 are still the shape of a drop.
Clean the contacts, the horse shoe metal part and the counter part.
That helped on my Gorgar

You can confirm whether or not the switch is working by going into the switch test from diagnostics.
Once in the switch test hit the "GAR" targets in sequence. When the "G" drops, 41 should appear on the display, "A"= 42 and then when you hit "R", it should say 43, then immediately change to 44, which is the all drops down switch. If you don't get a 44 with all three drops down, you know the problem is in the all-drops down registering.

This could be a problem with the slider boards or the wires connecting the boards together. You need to make sure that the wires are all soldered securely. If the wiring is good, you may need new slider boards. You can get these from Hans at Siegecraft:

http://www.siegecraft.us/pinball/sliders.html

Or you can do away with the sliders entirely and send a note to Steve asking him to put you on his list for when he releases his microswitch replacement for the drops:

http://pinside.com/pinball/forum/topic/replacement-for-those-sliding-horseshoe-contacts-in-williams-drop-targets

viperrwk

John's Jukes sells the contacts.

http://www.flippers.com/catalog/product_info.php/horseshoe-blade-switch-p-2213?osCsid=0cb8fa4ec1a8b77f9481addf09e5fb9a

viperrwk

Thanks for posting your progress.
Glad you seem to have it tracked down.

Look on WWW.Flipperwinkel.nl
Click on "On-line shop"
Find "Contacten en Switches" and click on it
scroll down and you will eventually find the picture of the horse shoe contact:

Price 5,50 euro a piece.

Sleepcontact rechts voor droptarget
ATTN international customers:
We do NOT accept Paypal, Creditcards or Cheques, neither do we ship COD.
There are also NO DISCOUNTS on larger quantities.
Dit sleepcontact zit in de droptargetbanken van Williams system 3, 4 en 6 kasten.
Dus tot en met Gorgar en in de prototypes van Firepower.

Other side found and cheaper:

www.pinballcenter.eu

find "Electronic Parts" link en click on it
find "switches"in submenu on the left of page and click on it
go to page 3 and on the top of the page you will find the horse shoe contact for 2,50 euro a piece.

I'm having the same issue. I'll do some tinkering and report back here.
-mof

Cleaned mine up, and the problem is 50-75% gone. Seems like a vibration on the table causes them to reset when they fail to reset. Usually takes 10-20 seconds, not a *big* deal. Much better than where they were before.
https://pinside.com/pinball/forum/topic/resto-gorgar-mof-20150301/page/2#post-2341546
-mof

Wondering if someone can explain how these mechanisms work?
What causes the targets to reset? What needs further adjusting?
-mof

It has been a while but I believe they are all daisy chained together so each target when down closes the gap and when all down the switch is finally closed. So in a three drop bank you have six contact points that all have to make connection and the wires in between the targets has to be good as well.
In the middle of each drop board there is the scoring indicator for each individual letter.

CNKay has this right.

Here's how to interpret the drops in switch test.

When you test the drops, the G O R drops are switches 18, 19 and 20 from bottom to top. When you drop one that switch number should register on the display. After you drop the third switch in the bank, the all down switch 21 should register. It doesn't matter which order you drop them, only that 21 should only happen after all three in the bank are down and not before.

So for example, if all three are up and you drop 18, that should appear in the display in switch test. Then if you drop 19, that should appear in the display. Then if you drop 20, 20 should appear in the display *briefly* then it should be immediately followed by 21 appearing in the display. If you're not getting this then the drops need to be taken apart, the horseshoe contacts checked and cleaned and then reassembled. Same for the G A R three drop bank.

Here's a vid of someone taking apart their Gorgar drops:

viperrwk

I re-bent the two contacts out even further, and we seem to be good.
Thanks again for the assistance!
-mof

Yeah they are touchy. If you bend them out just a tad to much the target will drop slow and or hang not enough and no scoring or reset. They are a bit of a pain. Poor design. But mine have been good for a while now knock on temper glass.

Love the vids your animations crack me up!

Darn "G" target is "slow" going down, and I cleaned and bent out the contacts a little more, which worked for a while, now it's back to its old bad self of not registering until a MIGHTY pop strike which shakes the machine enough to register the "G"

WHAT TO DO...

-mof

Standard approach for me is to strip and clean all the mechs, clean the mini circuit boards with old wet n dry and use a very light smear of teflon grease on surface. If the horseshoe contacts are too worn or not springy I've replaced with these http://www.homepin.com/horseshoe.html

Yeah slow going down and the contacts are out to far use leaf tool if adjusting
They need to be at the same height as well. If the board is warped or screw getting loose then all down may not register.
I used deoxit for lube
once adjust had them act up once in like ten years.
May need to build up trace with solder as a last resort

this one?
http://www.amazon.com/Booster-Electric-Connection-Enhancer-Lubricant/dp/B0002BBVN2/ref=pd_bxgy_MI_img_y

Yes that is the ticket.

This is the same stuff but available in a lesser amount at a lesser price.

mK0fY3BApucEdRO8jp4NPPg.jpg

What is that a 3ml tube? Yes cheaper but only 55 drops of solution. What is it 5.00??