In message . com, JJ
Jones writes
We have a weird problem on 2 HP Laserjet IIP printers. If you run a
continuous print-test (Hold down Alt + Test for 5 seconds), the first
page comes out very faint. But each successive page gets darker and
darker until about the 10th page is almost perfect.

It's strange because we've had several of these printers for many years
and now 2 of them are doing the same thing.

I tested their cartridges on a good printer, and the cartridges are
fine, so the cartridge is not the problem.

Does anyone have any ideas of what the problem is? We're trying to get
some idea of the cost of repairing these things, and whether it's
worthwile.

Its almost certainly not worth repairing them. IIRC if you pull down
the front cover and look sort of centre top inside just above the toner
cartridge there is a brightness slider, fiddling with that may help.

--
Timothy