How to remove 574 error in Nellcor N- 595 ???

Look up the manual and find what the code means, then fix it could be as simple as remove lens cap.

I believe error code 521 refers to a low battery that requires replacing

An 8-pin DIN type or 9-pin sub miniature D (Nellcor) type female connector used to attach the SpO2 sensor assembly to the monitor is not present. Here's a link to the service manual for this device.Passport Service Manual

Found some at this link. http://stores.medsurgequip.com/-strse-3699/DISS-Female-x-DISS/Detail.bok

new toner cartridge.

hi,
As it is a thermal printer, the printer head can become faulty. If so you will get a poor printout. It is not easy to say by words how can you remove and repair the same. if you can sent me your email id then i will sent you its service manual. It will help you to remove and reinstall the printer. As its in PDF format and sized large can't sent it through fixya. So if you sent me your email id as a replay to this through fixya, will sent you the service manual.
ok

Check with a physician who will give you continued care.

Link to Manual: http://www.welchallyn.com/documents/Patient%20Monitoring/Vital%20Signs%20Capture/Connex%20Vital%20Signs%20Monitor/DFU_VSM6000.pdf
Hope this helps.

if you are talking about the patient cable.  Then yes it is available from www.medicaldevicedepot.com

it means you have a bad Spo2 cable....