Hi mrbanjo +
in Europe we can buy new FINDER relays of all kind - simple relays and ministeppers (1 -> 2 -> 3 -> 4 - > 1 -> 2 ...) or relays with "built-in delay" (delayed pulling in etc.) - I LOVE the FINDER relays.
Here the link for an simple 24V Alternate Current Relay with 2 Make-and-Brake Switches (we could use in Gottlieb and Williams pins): http://www.tme.eu/gb/details/40.52.8.024.000/miniature-electromagnetic-relays/finder/405280240000/ --- I click below of "picture of the relay" on "Specification" -> http://www.tme.eu/gb/Document/29c8f5122befaa693b8c4b815543fabe/s40en.pdf -> on the first page - on top, outmost-right -> the relay is now of color blue. I scroll down to page-7 -> down on the bottom, on the left -> the "24 VAC version of this type of Relay" runs well on 19.2 VAC to 26.4 VAC.
On top of page-7 is a list for "Direct-Current-Type of this kind of relays" -> the 9.024-coil-code "24VDC" relay runs well from 17.5 Volt DC to 36.0 Volt DC (((the 9.036-coil-code "36VDC" would fit in the Chicago-Coin pin - it runs from 26.3 VDV to 54.0 VDC)))
From the fact "FINDER" produces 24VAC-Relays AND 24VDC-Relays I read: When we have a DC-Relay -> we MUST have Direct-Current - the 24VDC-relay does not work on 24VAC.
The picture in post-41 shows the information "Sigma 67R4 24 DC" -> THIS Relay NEEDS DC. I think I read: contact-points on the switches can handle well up to 120 VAC, can handle well up to 3 Amperes. I also see the drawing of four Make-and-Brake-Switches.
mrbanjo, Yes -> post-42 -> JPG -> encircled-red: The diode (used on all the problematic relays) - the diode in question. I believe: When this doide is "broken" and let current flow in both directions -> the Specific Sigma-DC-Relay gets AC-Current and acts faulty.
Post-26, JPG lower part -> schema-snippet-A-1 -> a diode for the several 100'000 points relays.
I suggested to make more than 100'000 pints -> does the relay pull-in and stay pulling ?
IF YES -> diode is GOOD -> diode is "5612-4004" --- the same diode is used on the problematic A-, B- etc. relays -> want to try the GOOD diode in place of "diode in problematic-area" ?
I am not good in electronics - I cannot help in testing diodes and capacitors ...
(((If You (beeing in the USA) cannot reach the site and the specifications (PDF) http://www.tme.eu/gb/details/40.52.8.024.000/miniature-electromagnetic-relays/finder/405280240000/ --- write here in pinside -> I can show stuff by making snippets using the "PrintScreen" button. Greetings Rolf
P.S.: About "new" relais: The disadvantage on FINDER-Relays: They only (mostly) have only TWO (Make-and-Brake) Switches --- when I need 6 switches -> I must mount three Finder-Relays PARALLEL (coils mounted parallel). Maybe in the US "easy to buy (?)" are OMRON-Relays: https://www.omron.com/ecb/products/pry/ -> General Purpose Relays: http://www.ia.omron.com/products/category/relays/general-purpose-relays/index.html -> for Control Panel: http://www.ia.omron.com/products/category/relays/general-purpose-relays/for-control-panel/index.html -> Miniature Power Relays: http://www.ia.omron.com/products/family/948/ -> Line-Up: http://www.ia.omron.com/products/family/948/lineup.html
mrbanjo, when "everything else" does not solve the problem -> want to buy NEW AC-Relays of 36 VAC, get rid of the diodes -> mount the new relays and do make new connecting-wires to the new relays (I believe: ALL new relays come with "Make-and-Brake" switches - we easily can use two of the three blades of an M+B-Switch to use for an Normally-Open-Switch / for an Normally-closed-Switch).