Designjet t795 printhead issue unknown

[hriosm]

Help please. My plotter T795 does not recognize any of the printheads. If I put printhead on a paper tissue , the 2 rows of ink show fine, but never completes printhead substitution. Run drop detector calibration and it fails, but if fails without moving carriage over the drop detector, just does not move.

Also, when running printhead substitution, it does not show any 52:10 error, corresponding to drop detector error.

Replaced drop detector and still not completing printhead substitution.

It seems to me like a printhead chip problem. How to know for sure before buying new printheads?

Does the plotter really use drop detector to detect bad printheads? 

[D Hook]

How much ink is in your cartridges?  If any of them are low, the printhead replacement process won't complete.  The carriage won't move from it's home spot if it senses a low ink level on any of the colors.  You'll want to be sure each color is around 25% full.  

[Repairatrooper · Accepted solution]

Also check to make sure that all the contacts on the printhead and carriage are free from ink or debris.