Check the systemvalue QCHRID. The value for characterset should match the characterset of the CHRID in your printer device settings.
Next check your printers setup. See what codepage the printer is set to and make sure you put the codepage on CHRID parameter of the printer device to that same value.
If this doesn’t work try setting the codepage of the device to 500. This is the most common code page and should work (Although it might give some swapped special charecters). Then try different codepages and look at the results.
WRKJOB yourWriterName/OutQ name
Check the joblog – you should see error messages