When I had a tftc I had the same problem. I changed the springs and targets (2 cracked) and it worked better. Still sometimes it takes a direct hit to knock them down. Also clean the assembly. Mine was a little gunked up and sometimes the targets would drop slowly.

Here is the spring I used I think

http://www.pinballlife.com/index.php?p=product&id=1457

There are only 3 drop targets and 3 springs.

Replace all 3, easy to do.

Targets:
http://www.pinballlife.com/index.php?p=product&id=572 1.50 each
Springs:
http://www.pinballlife.com/index.php?p=product&id=1457 .75 each

Get new TFTC target decals from various sources online or possibly PM me for alternate ideas

Some good pics here (scroll down to the drop target section)
http://warpzonearcade.com/?p=552

RussMyers

Remove the drop target assembly. Take some pictures of it... then take it apart, clean it all up, and put it back together. Probably has old black gunk and oil on it. Never oil these things. They are meant to work dry.

This is what I did. Mine had two different spring sizes and it made a huge difference. I took mine off and let them soak in soapy water overnight and scrubbed the hell out of them ( the target decals need to be replaced often with these anyways).

Hi, I am trying to install in my pinball a new bloc of drop target instead of stand up target. I need some help to connect the 2 electric wire to the coil of the drop target assembly. I have got a brown electric wire and a green electric wire. Could you please post a pic of of the coil with the 2 electric wire in order to see the correct connection. Thanks a lot for your help.