I wanted to show my result after a warm dishwater soap. It is from the Canon IP7250 printer but still no yellow. Any ideas? Maybe Ink cartridges, nozzle... etc?
The missing yellow could be caused by an electronic defect in the print head and/or the logic board. It could also be caused by clogged nozzles, a blockage in the print head yellow channel or a defective cartridge not delivering ink.
To determine if the problem is electronic or caused by an ink blockage you can do a stamp test by pressing the underside of the print head against a soft tissue paper after having done a nozzle cleaning from the printer driver's maintenance. If yellow is present in the stamp the fault is electronic and only a new print head might cure the printer. If yellow is absent something is blocked and you might have luck cleaning the print head and/or the yellow cartridge.
You can test the yellow cartridge by holding it over a sink and blow gently into the vent to expel a drop of ink. If this is not easy or possible, the cartridge is blocked. You can repeat the test with one of the functioning cartridges to get a feel for how little effort is needed to expel a drop of ink.
Here is a stamp test that shows pigment black missing but all the colours are present.
The picture is from this post, that has a suggestion of a cleaning method.
One must always ensure that as many variables are accounted for when trying to diagnose a printer malfunction. Using either a new Yellow cartridge or a known working one is imperative or else you may be chasing your tail.
If the complete lack of Yellow is due to the dreaded Yello Gello, then soaking/flushing using Windex with Ammonia D (original formula) is the solution to try to dissolve the clogging. Simply speaking, water, and maybe other solutions or solutes, is the cause of the Yello Gello as it dilutes the OEM Canon ink to a critical point and then the reaction occurs.
@PeterBJ 's suggestion to use plastic tubing connected to the Yellow ink inlet on the print head to allow gravity to work its magic has been successful for a number of people on the forum.
Could this be a pure electronic failure? Maybe, but that would be rare indeed, and a new print head should return the printer to proper Yellow function. However, we cannot know for sure.
Most important rule to remember is this equation YI+W=YG, Yellow Ink plus Water equals Yellow-Gel. After a water based flush of the head do not immediately try to run inks through the head. The Yellow will turn to Gel.
After a water flush you definitely need to flush with an Ammonia based flush. But the flushing solution for the print head also contains alcohol (search these forums). This is necessary to make sure that during the flush all the water molecules missed by the Windex are at least picked up by the alcohol. That trick is used in cars, remember that little bottle of gas-line-anti-freeze in the winter, or in industry for drying out airlines.
Lastly I recommend to make the last flush straight (classic) Windex with D. Keep all water away from the printer head. Dry the print head parts with napkins, especially the contacts, but do not dry the ink channels pads. In other words keep the ink paths moist. Install in printer, install ink carts, and immediately run check patterns, This worked very effectively for me. On the fourth pattern I had no more streaks. That was on regular paper. I don't know if printing test patterns on Photo paper is actually recommended. Are the patterns to much ink concentration? I have not try that.