7500 will not light

Hello tatasteve 

Thanks for using Community.

Which are the Forward and Reflected values? Does the Forward Power reach 1200W ? If not reaches this values,I suggest that put plasticfilm at the entrance torch , and try to ignite plasma in this condition and check the Reflected and Forward Power. If in this way, plasma lights , some air leak can be in the sample introduction (gas nebulizer connector, gas tubing...). On the contrary, the  Reflected power doens't reach 1200W, please contact with your Support Service

Best Regards 

Hello tatasteve 

Thanks for using Community.

Which are the Forward and Reflected values? Does the Forward Power reach 1200W ? If not reaches this values,I suggest that put plasticfilm at the entrance torch , and try to ignite plasma in this condition and check the Reflected and Forward Power. If in this way, plasma lights , some air leak can be in the sample introduction (gas nebulizer connector, gas tubing...). On the contrary, the  Reflected power doens't reach 1200W, please contact with your Support Service

Best Regards 

Hello

Thanks for the reply, the forward power only reaches 750 W and the reflected power shows 260 W as the plasma shuts down.  The spec for reflected power in analysis mode is <20 W, I think this is where the problem lies.

Regards

Yes, Reflected Power is high, it should be <150W and Forward Power 1200W.  You can remove the shield plate, and try to ignite plasma without this:

Another point that  you can check is work coil, torch, bonnet.... If the problem remains, please, contact with your Support Service

Thanks 

Best Regards

Try to ignite the plasma, without fixing the shield plate. Due to poor quality of argon gas or leak on gas line, reflected power will be above the limit and prevent the plasma sustain. Sometimes, the plasma sensor fiber optics tip is damaged, needs to cut the edge of the fiber optics cable.

Hi,

the 7500 has this „gold finger“ which will provide a contact to the interface when the torch box moves towards the Cone. 
Have a look at the contact plate, if there is some „dirt“ which is isolating this contact. 
also you can try to turn this spring loaded gold finger 90 degree axial. 
best regards 

chris 

Please check it as below parts condition.

Best regards,

Hi Chris

The contact plate on the torch box was badly corroded so I gave it a good clean and also cleaned the end of the "goldfinger" and magically the plasma lit first time.  Thank you very much for your help, I can't believe it was something so simple.  Just out of interest are you an engineer or ICP-MS user, either way you have made may day I can get on with some work.

Thanks again

Steve