Hp colour laser issue

[FuzzyLogic]

Ive got a HP CM1312NFI which recently had all the toners replaced (genuine HP). The printer doesnt get used very often and today tried to print a colour document and the red text is printing as yellow. A bit of digging around and running test pages is showing that the magenta toner is not printing anything.

Status is showing it as 87% full. I tried swapping a known working colour (in this case Cyan) with the Magenta to see if it was the toner or the slot but the printer throws up an error message saying incorrect supplies

Any ideas how to fix this please?

Edit to add that opening the front and rear panels and running an engine test page produces the same result - ie no red / magenta

[imck]

Toner Cartridges sometimes have a strip you need to pull out.
Did yours and did you remove it?
You can try to give the toner a gentle rock from side to side.

Failing that, send it back to where it came from.

[FuzzyLogic]

Yes - the toners had plastic covers on them and a pullout strip when they were new.

The toners were new in May, so I contacted Cartridge People, who I bought them from. Big thumbs up for the customer service here because they sent me out a replacement FOC that afternoon and it arrived this morning.

Unfortunately the replacement toner has not fixed the problem, so I guess I have a failure somewhere else in the printer that affects the magenta only...