Which toner fits the HP LaserJet Pro M102a?

One indicator light for two consumables

The M102a has no screen: it communicates through an indicator light. When it comes on or flashes, nothing says which of the two consumables is involved — and since they are not replaced at the same rate, the question genuinely arises.

Two markers settle it reliably. Counting first: the drum lasts about seven toners; if you have not changed seven cartridges since the last one, it is not the drum. Then the look of the page, which is the surest sign: a toner at the end of its life gives pale areas, often on one side of the sheet, that improve when the cartridge is shaken. A worn drum instead produces repeating marks — dots, lines or grey veiling that come back at exactly the same interval down the page, because they correspond to one turn of the cylinder.

The HP software installed on the workstation connected over USB shows both levels separately: it is the simplest way, provided it is installed.

Does the drum really need changing?

Yes, but rarely. On a machine for which HP recommends 150 to 1,500 pages a month, the 19A's 12,000 pages represent several years of use. Many M102a units are scrapped without their drum ever having been replaced — which is no problem as long as the pages stay clean.

The drum is changed when repeating faults appear, not on a fixed date. Replacing it early gains no quality at all.

What the machine can do

It prints, and only that: no scanner, no copying. USB connection only, a 150-sheet tray, 22 pages per minute, manual duplex, a maximum cycle of 10,000 pages a month. It is a standby printer for a single workstation, and its sizing confirms as much.