Really in need of suggestions I have run out of ideas.

[ThrillaMozilla]

If I understand you correctly, you put in a new OEM magenta, everything was fine, then you started to tinker again. Just put in the new cartridge, do a head cleaning, and then LEAVE it in. Leave the printer turned. on. If everything is still fine and remains fine, then your problem is solved. And you know there is a problem with your other cartridge or with your refilling technique.

 

[mikling]

The problem occurred twice and each time it sat with the cartridges in place. Clogs as stubborn as this do not occur that easily. Many folks approach the transistor in that they are either on or off. I have already described that those states are but two of three failure modes. With the third failure mode, you can get a leaky or partially on transistor or one that conducts erratically. If this is sufficient to put the nozzle in a partial on state, you will get the ink in the nozzle clogging over time due to dehydration, if the on state is at a high level, you get the ink solidified and a serious clog is a result. I've had enough experience building high performance hi fi amplifiers and should have seen this possibility years ago and should have realized something about this earlier.
Now when the transistor is at a leaky state, all bets are off on in its conduction characteristics...thus when used, it heats up a bit as normal but at these higher temps it may fail to work. The only argument is that at higher temps the gain should increase...but we don't know the circuits that are actually defective and when something doesn't work right...it is unpredictable to a certain degree.
OEM and flushed carts have been tried and not shown to be ink starved as very earlier it was described as such....but we should not dismiss the possibility of electronic failure.

My MG8120 printhead is such a victim. I still use it as it prints perfectly in high resolution mode, but somewhere the signalling and conduction in non high resolution mode is defective. I suspect my old Pro9000 was also a victim. It took out two printheads and the second one lasted less than 50 prints and the same channel was affected....ink? as fresh as it gets from different batches at each refill and I get my shipment at least once a month. That led me to suspect the printer logic board as the culprit. I know of another one where overnight the printhead on one channel becomes clogged and with the second printhead, something identical occurs...that one smells of logic board to high heaven. All printers had their power on continuously.

As a result, I would now favor only turning on the printer when it is needed..something that Canon recommends. Maybe they know or are aware of something?

 

[ThrillaMozilla]

I hear you, mikling, and it all seems to describe the symptoms. But I think he should check one thing at a time, and it sounds like he is not doing that.

There are also things that can go wrong with flushing, refilling, and changing cartridges. The main problem is magenta, and maybe a little problem with K. I just think that he should leave the new Canon magenta cartridge in there. If that gives trouble, THEN would be the time to suspect the print head or other electronincs.

 

[pearlhouse]

Well I got a good nozzle check to print out but the magenta was a little weak in brightness. So for now I have shut down the printer and pulled the plug. Ill give it 24 hours to see if anything happens.

 

[PeterBJ]

Could you make an extended nozzle check from service mode and upload it? This check will show if all nozzles are firing or the too light magenta is caused by loss of half the nozzles in the magenta stripe. If missing nozzles show a regular instead of a random pattern, the problems are caused by an electronic failure, maybe caused by leaky transistors or??

 

[pearlhouse]

Could you make an extended nozzle check from service mode and upload it? This check will show if all nozzles are firing or the too light magenta is caused by loss of half the nozzles in the magenta stripe. If missing nozzles show a regular instead of a random pattern, the problems are caused by an electronic failure, maybe caused by leaky transistors or??

Will do when I turn it back on tomorrow. Question???? How do I get into service mode??

 

[PeterBJ]

Normally the procedure for entering service mode is found in the service manual, but I found no free download of the service manual. If the printer has normal push buttons the procedure from this post that also has an instruction for using the service tools should work. If the procedure for entering service mode doesn't work, try pressing the stop/resume button 5 times instead of two.

If the printer only has an on/off button and the rest of the buttons replaced by sensor fields, then the procedure from this post and this post might work for entering service mode.

For the service mode operations I recommend the newest available service tool V3400. This tool works with all Windows versions from XP and newer, both 32 and 64 bits. This post has a download link.

Even if your printer might be wireless, the service tools only work with an USB connection. No hubs should be used, and only the printer you want to perform service operations on should be connected to the computer.

The service tools only work with Windows, they don't work with MacOS or Linux.

 

[turbguy]

The SHAPE of the missing magenta in the test prints is the largest evidence of starvation. Ink is being expelled from nozzles near the ends of the nozzle row, WHILE AIR IS BEING PULLED INTO THE CENTER BAND OF THE NOZZLE ROW OPENINGS, FROM THE DISCHARGE SIDE, STARVING THEM! Something is stopping sufficient ink flow into the space behind the magenta nozzles. If it were my printer, I would disassemble the printhead and force fluid through the passageways, but only if I had a spare on hand...

Also, it COULD be a bad gasket below the cart outlet. You might try switching them around and see if the the issue moves to a different color.

 

[PeterBJ]

I agree with turbguy. Ink starvation is also my prime suspect. As a new OEM cartridge brings no improvement, the cause of the problem must be elsewhere. I see two possibilities, a gasket not sealing properly or a clog in the fine ink channels in the upper plastic part of the print head. Here is a post showing a magenta ink starvation print pattern. It looks very similar to your print pattern

I wonder if the ink could be the cause of the problems. If microbial growth has taken place in the ink, the ink is likely to cause problems with clogs. I have seen a shelf life of two years mentioned for IS inks, but I think that only applies to unopened bottles. I think the shelf life of an opened bottle might only be half a year, depending on storage conditions.

So if you manage to solve the problem, I recommend to discard the magenta ink and buy new ink. It might also be a good idea to replace the magenta cartridges or at least flush them thoroughly.

 

[The Hat]

I reckon you head must be in a bit of a spin with all the good suggestion you’ve had so far.

There’s only one further thing that I can add and that is for you go back to the start of this post #1 and read the lot again slowly then figure out the best suggestion and go with that, just start afresh so to speak..