Dover Hydraulic 2 Landing Elevator 1976 Vintage.

Schematics are hard to publish here (they tend to get grayed out and have too small type to be readable). Even so, it might be worth a try.

It seems that the control system is too complicated--too many relays, etc.

What is the circuit elements downstream of 48V S-circuit? Trace it, if it includes supply to series of relays especially smaller ones, then its time to replace all because sooner or later, the same coil lost resistance problem will recur and its quite a hassle to your part and owners as well. You don't want anybody there to be trapped especially this new year's eve.

Anyway Happy New Year and God bless you Edward!

Is this a rotary "pie cam" floor leveling system? Or a "floor bar" switch type?

If so; make sure the appropriate carbon brush switches have less than 1 ohm impedance through the metal pie cam or appropriate floor bar.

If the contacts do not have very low resistance through the circuits either the brushes, brush shunts, or pie cams are fouled or not properly adjusted.

These type of switches are non-lubricated and any lubricant applied to the conducting surface and/or switches will defeat correct switch and elevator operation.

Elevators are specifically designed so that no lubricants are needed on any equipment or controls other than the gear case and motor bearings.

The reason for this is to keep dust and other contaminants from adhering to the contact surfaces and/or bearing surfaces via the lubricant and causing component failure.

Hope this helps.

I have checked all the relays, and ohmed the coils, all good.

I believe when the elevator contacts the slow down switches there may

be a timer that helps control the slowdown feature until the final landing

switches are contacted. If this is correct, then one of the timers is not

working. Will have to check them. This elevator has a TMS relay that is

controlled by a TMT module that has a diod, a electrolytic capacitor, and

a resistor block. Will have to check each component. The slow down, leveling

feature should last about 5 seconds for leveling purposes, and is not working

at all.

I also maintain a 1964 Dover elevator, and it is easier to figure out that this

one, because it only has the larger P&B relays, and about the only maintenance

it needs is replacing relays when one wears out. And you can still order new

relays.

These IBM relays are very hard to find, I have to find a near type relay, and take

the wires out of new relay and put in old relay with burnt wires.

I will start at your replacement and rewired relay and move it to another position and move a good IBM relay into that position, if the fault move with the rewired relay then that is where your problem lay. Untill you did that you can not fault find futher. Electronics seldom have multiple faults, except if it was hit by lightning.

Swells would have the same effect as lightning at frequent occurrence in long time.

You said surge happened right?

It might caused by below to one or more of the relays or switches.

Nasty things happen inside switches contact points, aggravated by frequency of contacts, load currents and aging (corrosion).

If it's comprehensive contract maintenance, safety is always first in line. You would not only loss clients if accidents happens.

Statistics tells us, most victims are technicians (veterans and rookie), other than the passenger.

Don't gamble life with just a piece of relay.

God bless and be safe.

Sounds like the either the stop and plugging(slow-down) are mis-wired,or contacts are bad.