Hi folks just acquired an LC2 which works ok, however when I initially plug the unit in from cold the lamp ramps up and down in brightness i.e. fades up to max, turns off quickly then immediately fades back up again.. This whole fading process slows down until after about 30 seconds everything settles and the lamp stays on!

Light levels without the IR filter seem to interfere, as does removing the load (switch built into lamp holder turned off) however the fault will resume once the bulb is back in circuit...

Ruled out interference from IR / CF bulbs etc. and the supply on board is a stable 12V from the off - the only thing I have noted is that it looks like a track may have burnt from the LM337 (variable regulator) at some point as the leg goes straight from this to the accompanying resistor, so I assume replaced and track was damaged or burt up (unlikely) can't tell which - voltage out is about 8v. Not sure what it should be!

Is there a Circuit for this unit or has anyone come across this rather strange fault before??

There are two capacitors on the mainboard of the LC2 (C17: 220uF/16V & C3 22uF/10V). Replace both of them and your problem probably will be gone (use 105ºC capacitors).

Thanks Blackrix some suitable replacements are on the way to me this week - I was going to replace the other three electrolytics on the IR board too, so fingers crossed!

I am going to guess B&O never released a CCT for this module then?

Olly.

ok I received the caps today (finally! OOS!) and have just fitted all. slightly reduced the problem. I am going to try some extra low esr caps I think which I have just ordered. I replaced C3 with a 47uf which almost cures the fault completly, however with the higher value it takes forever to initially charge to the point that the lamp switches on (when C2 reaches about 4v!!! After this everything works fine!

One thing worth mentioning is that someone has definately done work here before - removing the upper board revealed a broken track which had been bridged! At least this was advertised as not working at all so I was always taking a gamble I suppose...

New low esr caps installed (Nichicon) and tried increasing C17 to 330uf and it exhibits the same fault :(

I can use it, I guess but it needs to be permenantly plugged in and permenantly connected to a load (i.e. no use of lamp socket mounted on / off switch etc.), otherwise I have to endure a rather un-natural lightshow for a couple minutes upon first switching on