I'm trying to repair my cornerstone monitor which is missing the color blue.

I've tracked it down to a driver chip (I think) - VPS10 (CRT Display video
amplifier)

If I disconnect the input pin (pin 10) the signal is the same shape as the
other two colors - red and green. The moment I connect the input back the
amplitute of the signal almost halves. I've checked the output pins as I
thought it might be pulling the input down - but no go. All
resistors/caps/diode check out ok.

Does it sound like the chip is faulty - is this a common fault? Can anyone
recommend a replacement - the local exeltroniucs shop doesnt stock them