HomeBrew Serial Receiver works intermittently

[Chris G. <net...@ho...>]

I built this serial receiver/transmitter a year ago for a remote PVR running 
Mythtv and the problem is basically that it will just stop receiving IR 
input every once and a while. I will be playing with a remote perfectly for 
a few seconds, then it will just stop for a few seconds or even a minute 
then come back.

IRW shows nothing when the it stops working, which leads me to think it's a 
hardware problem. Since then I've actually switched the whole computer 
(mobo+cpu), and even tried my other remote and it still is doing it. I'm 
almost positive this is a hardware issue with the circuit but I have no idea 
where to look, what to test.. any ideas?

I used the standard Serial Reciever design 
http://lirc.org/images/schematics.gif and added the improved transmitter: 
http://lirc.org/improved_transmitter.html, which actually works perfectly. 
This is the second set of IR's I've built and I don't have this problem with 
the other.

I'm running Gentoo Linux, 2.4.23 (before), 2.6.7 (now) on the box that 
doesn't work with lirc 0.7.0_pre4.
The one that does work is running 2.4.23 still and lirc 0.6.6-r1 ebuild.

Any information on what to test or look into would be great, this is driving 
my family nuts as they use the PVR all the time and it gets stuck fast 
forwarding etc :-P