My Collection: Coughtrie FB.16 Mk.3

This Mk.3 Coughtrie FB.16 was an eBay win, and arrived in the collection on 5th May 2026. It is a 1970s example, and has both original ballasts and one working lamp it came with. With special thanks to Coughtrie for sending me the catalogue page for this fixture.

Unscrewing the cover screws allows the cover to hinge downwards. This exposes both tubes.

One of these is EOL, and one is working but has quite the number of hours on it!

The sticker on the gear tray reveals some details about this luminaire. First of all, this is a Mk.3 (1970s) version. It is also parallel circuit which has the interesting effect of allowing just one tube to be fitted and lit.

The parallel circuit is visible below on the back of the gear board. Both ballasts are original.

"7647" on the capacitor I believe refers to the 47th week of 1976.

The luminaire is fitted with a cut-out connector for easy servicing.

Both ballasts are Coughtrie R 3501s.

Both starters are also identical to eachother, although probably not original.

I fitted a new BELL tube (bottom) and the top one is one of the Crompton tubes the luminaire came with - heavily blackened.

The difference in brightness is very apparent even though the cover.

I also had a play around with fitting red T5 tubes: