Spawner in the Dark, but not spawning

[DicheBach]

I found a vanilla zombie spawner on the server I play on. I like to build "old school" type water elevator + drop-damager (along with some redstone controlled pistons and lighting to turn it off) mob farms, and built a number of bases in SP around such spawners. The spawner gets a sealed chamber that is 9x9 and 6 high, the water slide, water elevator, and drop are all sealed up too. The ride the elevator up 12 to 15 blocks then back across the top of their spawner and then drop 19 to 21 blocks and are sealed up with only their feet showing through half block gap. I use all the space around this "contraption" for my base: labs immediately under the spawner chamber (which has a two or three block thick floor to prevent drips), logistics storage area whereever, farms, etc. I just stack it all up on top of and underneath as well as around the spawner, trying as much as possible to make the areas where I work and linger be within 16 blocks of the spawner. It is a lot of fun to build these, and yes I know there are auto-spawners in tekkit and TL, but these are fun to make too. I've done this a half-dozen times or more in both tekkit and tekkit lite worlds.

 

I got the basic design from this guy ToZaTop, who has a tutorial video here:

So, in sum, I (pretty much) know what I'm doing. But I'm having two issues I've never seen before.

I have installed Minefactory Reloaded Road Lights with redstone wiring to turn them on off (and they do turn on and off), as well as pistons to turn the water flow off (which also work). I have not yet completed the upper works (water elevator, water slide and drop) because I've encountered these two issues:

1. Even when the spawner chamber is dark inside (I can see red hatching on the floor with F7 activated), and I'm standing just outside the chamber peeking in a window (so only about 6 tiles from the spawner) no zombies are spawning. I noticed this last night and have fiddled with it a bit today but I still cannot get it to work.

Maybe the chunk isn't resetting? Is it possible for a spawner to "malfunction" somehow?

2. I'm seeing a strange effect with the Road Light blocks that I had not noticed before. When I turn off the redstone power to the light circuit, the do get dimmer, but they do not go all the way "off."  I don't know if there is a delay maybe or what, but I've noticed if I just tap on each Road Light block it goes completely "out" (meaning it stops emitting low light. Immediately after I flip the switch, the chamber is still sufficiently lit up that there are no red hatchings on the floor. When I go around the tap on all of the Road Lights it goes completely dark inside (except for the light from the window where I'm peeking in which is minimal) and the red hatching appears. So basically the problem is the Road Lights do not go completely "off" when they no longer have redstone power, they seem to remain half illuminated for a while, though I don't know if they eventually go completely dim on their own or not. I had a fully functioning spawner in a Tekkit SP game (but I deleted it) in which I used the Road Lights to turn the spawner on/off and did not see this issue there.

Anyone have any ideas?

[AetherPirate]

I think I recall a bug with those lights, your suspicion is correct, they are never really off. Remove the lights or cover them with dirt for testing and see if anything spawns. 

[DicheBach]

Thanks I'll check that out. Your recollection that there was such a bug makes it worth the trouble to replace them with some other light source. I can always use them in other places in my base.

They seem to function properly in Tekkit.

Any recommendation on alternative light blocks?

[DicheBach]

Yep, removing those blocks seems to have fixed it. Weird thing is, they "are" off, at least as far as the F7 detector and the visual rendering. But evidently the spawner thinks they are not off. Guess I'll use the lamps that use "lumar."