Help with Mutoh 1304 - still have faint banding lines after replacing tons of parts

Hey folks,

Hoping you can help me out...I'm ready to throw my printer off a cliff...or perhaps just myself.

I've got a 2008 Mutoh VJ1304. I'm the original owner, it's been meticulously maintained since day 1. I'm running a bulk ink system from SolventCartridges.com and using FlexiSign for RIP (I want to switch to Onyx).

A month or so ago my black nozzles were misfiring (all others were perfect), I did multiple head soaks/washes, all the usual "cleaning" stuff, all with no luck. Called my local service guy ($165/hr + mileage + $95 on-site fee) and he came out and said it was my black dampners.

Fast forward a couple of days, dampners were replaced, problem got worse. Instead of only missing a couple of lines on the nozzle check, I was now missing all but two lines on the black nozzle. Other colors still perfect.

Tech comes back out and says, "your printhead is shot." Since it was my original printhead and 4 years old now, I took his word for it, bit the bullet, and paid to get a new one installed.

Fast forward two more days...now my printer won't print black. Period. All other colors will print, but no black. Not even a drop.

Tech comes back out and says "your maintenance station is shot" so I shell out another $650 in parts to replace the entire capping station/pump assembly.

Printer is now printing all colors, nozzles are all firing perfectly, but I have faint banding lines that won't go away. I've never had banding lines like this before. Never had banding lines at all, actually. They are faint now but I notice them and it's not okay. I've tried every option in the settings to see if I can fix it (wave, fuzz, fine, uni-lateral, bi, heater settings, etc) and nothing makes a difference. I cleaned the rails, the t-fence, everything.

Anyone have ANY ideas what's going on? The last thing I want to do is call the same tech that's dune such a "good" job (NOT!) so far.

Please, please, please help me! If anyone out there is near Seattle I will pay you to come work your magic. I'm tired of dealing with incompetent techs who don't know what they're doing.

Thanks in advance!!!!