door strike replacement

Hello
I noticed that part of the door strike plate is broken on one side and the strike assembly is no longer properly attached to the metal plate screwed in the door.
now, how exactly do I replace it?
there are 2 floors in the house, with 2 intercom units at the main door and one unit on every floor. the intercoms for the 2 floors are separate. both intercoms have a door release which operates the same door strike. there's only 1 wire going into the strike.
the intercoms are model Aiphone C-ML.
in the garage all the wires from the intercoms go into this junction box and they're all tied together in various configurations (it's a huge mess).
there are the 2 transformers for the Aiphone intercoms plus a third very large unit from ATC-Frost. ATC-frost is a transformer company, but this is not a standard transformer, I assume it also has a relay inside because the door release wires are combined before going into the transformer, so one release wire (pair) goes in the transformer and one wire (pair) goes to the electric strike.
if I change the strike do I have to change the transformer too?
what should I look out for before buying a new strike? are the intercom's "door release" signals standard?
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Strikes come in different voltages so check the output of the transformer. Many can be activated with either AC or DC with one being silent and the other buzzing. Other than that just find something that fits without too much modification.
From:mr sparkle snipped-for-privacy@shine.com

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mr sparkle wrote:

I think what you should look for first is a name and model number on the existing broken strike and see if you can Google up specs and/or where to purchase an identical or similar piece.
Failing that, use a multimeter to measure the voltage across the strike when someone pushes the button. You say there is "only one wire" going into the strike, but it mst be a two conductor wire, 'eh?
A multimeter set to measure DC voltage won't show much if any response to AC voltage, so If you get a reasonable reading, say in the range of 10 to 30 volts with the meter set for AC, but not much if anything on when set to DC, you'll know it's AC operated. Then take a WAG that if the voltage is less than 15 it's a nominal 12 volt unit, and if between 15 and 30 it's a 24 volt one.
HTH,
Jeff
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My name is Jeff Wisnia and I approved this message....

(W1BSV + Brass Rat '57 EE)
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