I have an HP Office Jet Pro 7740 large format printer that has seen little use since I retired. Went to print something the other day and a message appeared - "ink delivery system failure" or something similar, it did identify the cyan and yellow cartridges as the offending cartridges.

I can either replace the entire printer (nearly $400), replace the identified ink cartridges (@ $35 each) or replace the print head and cartridges (@ $150 total).

The printer head is easy to replace . . . about as easy as replacing the ink cartridges.

Any words/thoughts of wisdom as to which direction to head? I do not NEED the/a large format printer any more, but 11 x 17 has been really nice.

Well, HP has lately been justifiably reviled for their practice of locking printers unless their brand of outrageously expensive printer ink cartridges are used. So, if you don't absolutely need it, consider junking it.

If you decide you do need one for large format, research Brother printers. I've had very good luck with them, aftermarket inexpensive ink works fine, and they just keep right on trucking.

But first, see if the printer has a "cleaning" cycle. Sometimes, that can unclog a dried printer jet. For a while.

Bet there is dried ink blocking the system, ran into that with my Brother after sitting dormant. Remove, clean if possible then reinsert the offenders. It’s wise to use the auto clean setting to where the printer starts up runs a clean cycle then shuts down.

My guess also. Inkjets that hacen't been used in a while will get dried, clogged jets. Check to see if the printer has a cleaning utility.

I got sick of dealing with the expensive HP ink cartridges which seem to only last a couple months whether you use them often or not. Took my 3 year old HP and threw it into the trash and bought a cannon which uses bottled ink. The total cost with ink supplies that will last more than a year was about twice what I would have spent in another 2 or 3 month supply of cartridges. The money i spent on HP cartridges over the past 3 years were about 8 times the total cost of the printer. HP is a rip off. They price the printers cheaply and make money on the cartridges.

Get and Eco tank and don't look back

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If you want to try to repair the printer, you can run some "cleaning cartridges" through it.
If you are refiller, you can make up your own (OctoInkjet Formula or Art Entlich Formula)
Art Entlich Formula = 2 parts Windex Original w/ Ammonia D and 1 part isopropyl alcohol.
Lacking that, check Ebay. I think there are a few selling cleaning cartridges on Ebay.

If you don't need color, look into getting a Brother laser printer.
All the inkjet problems go away and printing costs go way down, especially if you use generic toner cartridges.

i had to junk a Canon printer because the ink dried and clogged the head. Couldn't ever clean it . I ended up getting a Brother lazer printer. I hardly ever used the color print anyway.

I agree 100%

I too suggest getting away from HP for $$$ reasons.

Nothing wrong with HP Laser printers and Lexmark laser printers are pretty good as well.
Aftermarket high capacity toner cartridges last me a couple years or more.

Edit to add: Hp Laser printers are the easiest to work on.