TSI Instruments dusttrak II 8532 - Replacing the Internal Filters

Chapter 3
40
The screen is now locked.
To unlock, touch UNLOCK and re-enter the model number. For 8530EP
models, 8530 should be used. After entering the model number, touch OK.
Note
If you happen to enter the model number incorrectly and touch
OK, you will be given another chance to enter it correctly. There
is no limit to number of chances.