More circuit help required please

Bipolar transistors are to some extent symmetric under interchange of collector and emitter. Simplified pictures showing a bar of semiconductor with the ends being emitter and collector and a thin base layer in the middle are, well, simplified, but there is _some_ truth lurking in them. However, the only reason I could see that being done deliberately is if the circuit is analog and the transistor's behaviour is relevantly different from the normal way around. This circuit doesn't look like that to me. Redrawing it a bit less confusingly with V333 E/C swapped makes it look as though V333 and V326 are being used in their switching regions, not their linear regions. The lack of negative supplies is hardly conclusivein itself; negative voltages could be developed in any of many ways. However, V325, R322, and V326 would make it difficult for the R335/V325/V333 junction point to get too far below 5V (admittedly this is much less true if R322's value is actually significantly higher). I also question the way R311/R310/R309 are all different. I would expect the red, green, and blue circuits to be electrically more or less identical, and different pulldown values does not fit with that. Indeed. I don't know how much you know about electronics at the relevant level, so it's possible what I'm about to say is unnecessary or has already been considered. Did these resistor values come from reading bands, or measuring in-circuit, or what? Note that R322 is in parallel with the C-B diode of V326; a simple ohmmeter put across it may end up measuring the diode drop instead. (To test this theory, switch ranges. A diode drop will usually give you approximately the same digits in each range - eg, 6.7 ohms on the 0-10 range, 67 ohms on the 0-100 one, 670 ohms for the 0-1K range, etc. Also, swapping the probe leads will give a different reading if that's what's behind this.) At least with R312 as high as 10K. If it were much lower, the diodes could be clipping diodes; a diode drop is not too far from about the right swing for a video signal. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B