These cartridge testers measure each Heat Resistor Selection Transistor and then identifi es on the LED readout the number of defective heater resistors. In a separate test it energizes the heat resistors to generate a block print test that will show any ink voids or irregularities caused by plugged or flawed nozzles.

For use on the following cartridges:
Circuit Tester CT8 #7230
HP45/41/6615/25/1823

Circuit Tester CT9 #7231
HP45/6615/6578

Circuit Tester CT56 #7229
HP26/33/25/29/49/6614

Circuit Tester CTLexA #7228
12A70/80/136/138/15M/10N16/26

Circuit Tester CT10 #7233
HP 6658/57/56/8727/28

Circuit Tester CTMH1 #7234
HP 15/45 /23/25/41/78 /26/29
6614/1816/17 Lexmark 50/60/70/80
15M/619/620 /1016/26