Laserjet 4240n printer won't take Q1338A toner cartridge

[amaisoupa]

I have a Laserjet 4240n and the 42A cartridge is getting low on toner.  Looked it up on HP.com and it seems that the 4240n can use either the 38A or the 42A .  Bought a sealed genuine HP 38A cartridge (Q1338A), and it doesn't go in.  Do I need to use 42A cartridges?  The 42A is 10000 pages.  The 38A is 12000 pages.

[Valsimot · Accepted solution]

You can only use HP 42 cartridge in your printer.

The HP 38 is for HP Laserjet 4200 series and it can't fit in HP Laserjet 4240 series.

[amaisoupa]

Thank you very much for the response.  You're right.  The 38A doesn't fit. 

The confusion is that if you shop for toner on the HP site and specify Laserjet 4240n, it shows that 42X, 42A and 38A will work.  Ebay also says that 38A will work with the 4240n.  They are wrong. 

If you have a 4240, use only 42A toner.   Thank you again.