Sounds like some inadequate troubleshooting advice was provided for this thread. Discovering the the vac pump is weak or damaged does not solve the problem of WHY the degasser is not working properly. Is it just worn out or has something damaged (contaminated) it? Most of the time, the causes are multiple, not one.
The HPLC degasser modules were not designed to be service by customers. The info provided in the manual is often in error and does not account for the many variations introduced by Agilent over the years. Voltage values quoted in the manual are not correct as the circuit used varies in each module and must be hand-tuned by the tech for the actual sensor used. It requires specialized knowledge and skill to know what is "correct" and how to service the module. Testing of each component is critical to determining first the condition of each part, then the cause of the failure(s) observed.
Often, replacing just the vac pump in these modules results in failure of the module soon after (days, weeks, months). That brand new pump is often damaged in the process. This is because the real problem that caused the vac pump to fail was not initially correctly diagnosed and repaired. The pump, valve and sensor can be contaminated from one or more failed vacuum chambers or use of the wrong vacuum tubing (some clients have installed AUTO store tubing in them! Please do not do that). Sometimes this results in serious damage, sometimes a simple fix takes care of it. There is no way to know for sure what is wrong with YOUR degasser unless the entire module is evaluated diagnostically by a professional to find out the true cause of the problem and then propose the correct repairs to restore operation. Note: Agilent does not provide "service" for their degasser modules, only replacement with another used (refurbished) module. This is cost effective for the manufacturer, but often costly for the client ($2,500 plus).
The good news is that you can often have the entire degasser module diagnostically evaluated, repaired and returned to you for a fraction of the cost of replacing it IF you send it to a professional degasser service company such as Chiralizer Service, LLC (USA). They are experts in ALL brands of degassers, stock all the parts and offer upgraded parts too. All at prices far less than what Agilent (or other manufacturers) charge plus have 1-2 business day turnaround on most repairs (super fast). For more info:
http://www.chiralizer.com/hplc-degasser-repair.html
