Does my orchid have a disease

[Andretg]

Hi all,

I just signed up to the forum and have been reading some very interesting discussions on here.

I have an orchid that I found on the side of the road (so no idea what species it is) and am trying to bring it back to health.

I recently repot it as the pot I found it in was too small and roots were rotten and overgrown inside it. I clipped off the rotten roots and removed the earth clumps sticking to them. I then repotted in woodchip and a little charcoal. I water it 1 a week by dipping it in a pail of water for 10 to 15 mins.

I live in malaysia where the weather is very hot and humid.

The plant lives in a shady area of the balcony where it doesn't get rained on but still gets fresh air and wind.

Its health has definitely improved and a new stem is growing strong but some of the older leaves have some brown patches which seem to be passing on to the others.

Does anyone know what this is and what I should do to cure it?

Thanks,

André