HP9836C colour alignment (grey scale tracking)

I would hope so. And this is an HP machine, from the 'good' days of HP, so it's likely to use somewhat overrated components. I acutally wonder if adjusting for a certain maximum intensity is the best thing to do to safeguard the eleectronics. If the phosphors have aged, it may bt that I have to turn up the gain so far to get that intensity that the beam current is high enough to damage the flyback, or the video output transistor, or.... I am wondering about measuring the average beam current when displaying the level 15 raster of each primary colour and making sure it's reasonable. Beam current is near enough the final anode current, so measuring that would do. But that would mean having a microammeter floating at 25kV wrt earth. What fun... Well, the thing is that no way could I afford a new photometer, or even a 'properly' recalibrated one. So even if I found one, I'd have the problem of knowing if it was anywhere near calibration. For most measuring instruiments I can think of 'sub^n standanrds' which would at least verify the readings were sensible (e.g. checking a voltmeter agains one of the voltage reference ICs -- it's not a traceable standard, but it'll at least show if the meter is wildly out). But I can't think of such a 'standard' for luminous intensity. Also, the 9836 has 4 bits/pixel in the the graphics memory, these are fed to a 16*12 bit RAM (colour lookup table), and then to 3 4 bit DACs. So there are a maximum of 16 colours o nthe screen at any time. OK, this is better than most of my other machines, but I am hardly likely to use it for displaying photographs or anything like that. No, the use of colour is for things lijke 'The red grpah is the I-V characterising with a bias of -2V, the blue graph is the same with a bias of -6V'. Which means the exact colours are not that important. HP make some comment about setting the grey scale carefully to avoid customer complaints that 2 9836Cs don't show the same colours, but I don't have 2 of them :-). So provided I am not going to damage anything, presumably by excessive beam current, I don't think it's going to be that critcial _for me_ So yse, I guess I do it by eye, possibly also checking the beam current. -tony