Cyan is leaking hard from the carriage assembly. The ink is all over the paper, platen, service station and cartridges. The printer will be needing a major cleaning because of all the ink. I believe it is the ink tube system. Printheads and cartridges are over 10 years old but seems to be working okay. The cyan printhead was replaced but the problem remains. I will be needing your ink tube system. I don't think it is the cartridge assembly. What are your thoughts. The printer will be needing a major cleaning because of all the ink.
Sorry to hear about the messy plotter you have. The ink tube assembly needs to be replaced. In the meantime, you should remove the ink cartridges from the plotter to prevent further leakage.
The Designjet 1050Cink tube system should be replaced.
You can watch a short instructional video on how to replace the ink tubes at: Designjet 1050C, 1055CM Ink Tube Replacement