Fairchild part replacement

The 817 bit rings a bell - look among the Panasonic datasheets.

......................might be NEC, but I'm pretty sure its the base number for an industry standard part.

Thanks Ian...

Looks like a DC sense

Number info matches the IC, except for the county of mfg.

Cheers

The AC input part was a few numbers away - possibly something like 837.

The 817 is indeed an industry standard. I don't know who originated it but it's common as a PC817 on my side of the globe. Available almost everywhere they sell parts.

Yep, but it's a slow opto, usually I'm sending data so I've never used this series and never needed 5Kv isolation.

Something 'happened' on the line. Interestingly enough all the Triplite products failed, but the APC stuff kept on working. At least the connected devices were protected. They cost >> more than the UPS. This UPS will wind up on something that just needs power cycle protection.

Cheers

It may well have been Sharp - but I think they've dropped some of their semiconductor lines, and opto could be one of them.

The ones in PSU feedback circuits are usually DC input, the AC input variety were at one time very common on internal modem cards, but most manufacturers switched to DC input types with a bridge rectifier.

My search for AC input optocouplers produced surprisingly few hits.

Sharp is the guys that still make it. PC817