Solo Plus LX Pressure setting

I have an old Respironics Solo Plus LX and I want to increase the pressure setting, I have tried holding both buttons down while plugging in the machine with no luck, can someone tell me a different method.

Thanks

these are what I was given when I obtained an old machine - of course it didn't work for mine - I needed a manometer to set that one - but hope these help

Respironics SOLO


First, with the machine plugged into a wall outlet, unplug the cord from the back of the CPAP. Now, press and hold the Pressure On/Off button (the round button on the left) and the Ramp button (the oblong button on the right) down at the same time while plugging the cord into the back of the CPAP.


The CPAP should come on and the elevation setting of Lo, M, or HI should appear. (LO=2500-5000 feet in elevation, M=5000-7500 feet in elevation, Hi=7500 and up in elevation.) To change the setting, use the Ramp button. Press and release the on/off button and the pressure setting will display.


To change the pressure, press the Ramp button and the pressure will increase 1cm of water pressure each time you press the button.


When you stop pressing the Ramp button, the signal light will flash one time for each cm of pressure to correspond with the new pressure setting. If you wish to verify the setting again, press the Pressure On/Off button. The signal light will again flash one time for each cm of pressure.


To exit and save changes press and hold the On/Off button while pressing the Ramp button once. The machine should quit blowing and the green light should light up.