diagnostic help needed

[Electric Ave]

Hi, folks. I apologize if this has been covered in the past but my searches have not turned my specific problem up.

I am helping some friends bring their SP-300V back to life. When I started, none of the heads were printing and the ink lines were filled with air. After replacing a few of the obvious and critical parts, the dampers and the captops probably being the key replacement parts, the system began to come back to life. The black came back the quickest and after 2 or 3 medium head cleanings, CMY test patterns looked very good but the black conitnued to have voids.

I am beginning to think that the black head is not necessarily suffering from some clogged nozzles but it looks like pixels are being shifted on the head. The pattern is the same each time, cleaning doesn't seem to change it. When I print the test pattern with text, I get ghosting effects above and below the characters.

I've attached a sample of the internal ladder test. There are some line deletions but there are also lines inserted where there shouldn't be any, as if they aren't being placed properly.

Could this a sign of a bad head or maybe the drive electronics upstream?

I've also replaced the wipers, the wiper scraper, the T sponge and the upper sponge.

Thanks in advance,
Fel

 

[sfr table hockey]

You have done well to recover the other colors but the black may be a bit more clogged. If you search head soak you may find what you need to do.

Basic things that can happen.

Head and get dried ink blocking nozzles (blank areas) and some just blocked enough to deflect the ink spray (thus shadows or miss aligned spray). May be able to recover.

If the head has had damage (head strike where the heads rubbed over the media or caught the edge of the media) or just gradual wear that has some nozzles just quit and you may never recover.

You should never rub the underside of the heads with swabs as that can damage the head. But slight pressure up under the heads with a swab soaked in cleaning solution can force cleaning fluid into those blocked nozzles and can open them up again. Just push up and not rub.

A head soak is better to try first as it lets the head sit in a pool of cleaning fluid and work its way into the head and loosen dried ink.

Several reg cleanings after that can recover some nozzles.

Keeping drain lines clear from blockage is a major key. If they get plugged with dried ink the pump can't draw ink through the heads and charge the heads.