VTIC 7210 ir detector data ?

Hi there,
I have an old Marconi spectrum analyser and one of the optical encoder controls has died. It has a pair of ir LED emitters and a corresponding pair of detectors type VTIC7210, which according to the circuit diagram are ir schmitt-trigger detectors, TTL compatible. As far as I can tell, one of the detectors is stuck low.

From google, I can't even determine the original manufacturer, never mind find a data sheet. I'd be glad if someone could point me in the direction of a data sheet so maybe I could decide on a substitute part, or even a vendor who would sell me a few ?

Thanks and regards

Well, I have a result -- not the one I expected though !

I contacted a couple of vendors who claimed to be able to obtain obsolete components, but they couldn't help.

I was surprised to find that Aeroflex (Marconi) still have the whole encoder assy listed as available, pn 44990/455, price 79ukp plus handling, particularly as the equipment is about 20 years old. Worth the price just to keep it going a bit longer.

regards..