Versant 80 won't print black (K)

[stev0]

Having an issue here with a Versant 80. CMY prints fine, but the K toner doesn't appear on the pages at all. We've tried swapping out the drum, and then the Developer Bias HVPS board but neither helped. Anyone have any ideas?

[adriansto]

Having an issue here with a Versant 80. CMY prints fine, but the K toner doesn't appear on the pages at all. We've tried swapping out the drum, and then the Developer Bias HVPS board but neither helped. Anyone have any ideas?

Presuming you have black developer and toner into developer assy what about the first BTR - inside the IBT assy?

[xcopytech]

Did you check developer assy rotation

[stev0]

Yes, we checked the first BTR in IBT assembly and the developer rotates fine.

[adriansto]

Yes, we checked the first BTR in IBT assembly and the developer rotates fine.

The print is from printer internal tests, copy or from Fiery?

[stev0]

The print is from printer internal tests, copy or from Fiery?

Both, when printing internal pages through the printer the b/w ones come out as blank sheets, the colour ones come out with colours and CMY greys (no K), when printing graphics from fiery the black (K) areas come out as white areas on the page.

The drums and developer unit seem to be rotating and operating correctly. We tested new toner and drum. We tried replacing the developer bias HVPS board but that didn't work. Did a NVM initialization. Checked toner path. And did a firmware upgrade (firmware upgrade was a little dicey, at the end the screen never changed and all of the buttons would blink twice then repeat, I waited an hour and a half and turned the machine off, then it restarted itself and the new firmware version showed up correctly 🤷 On a probably unrelated note, after the NVM initialization, it thinks the scanner cover is open when it's closed and closed when it's open... strange.

Things we haven't tried yet, that I'd need to figure out how to test:
-Power supply for/or the K toner dispenser motor
-Stripped gears somewhere that might cause the toner not to dispense
-My tech suggested maybe the motor that lifts the K roller up under the transfer belt or power supply for that, he checked the roller itself and it's in good shape. He's thinking it's a power supply issue somewhere, and he knows a lot more than I do but he doesn't generally work on production machines.

[adriansto]

There is sensor for up / down first BTRs so if that do not works will be error pop-up on printer. But if you do not have voltage on black 1BTR there is any error displayed. First you must check if you have image on drum.
Also check for obstruction on laser path from ROS to drum surface.

[stev0]

There is sensor for up / down first BTRs so if that do not works will be error pop-up on printer. But if you do not have voltage on black 1BTR there is any error displayed. First you must check if you have image on drum.
Also check for obstruction on laser path from ROS to drum surface.

An update, the black developer was really low so I filled that. Now the prints look like attached image. My tech is here again having a look, he thinks the issue is between the developer and the drum, and likely a power supply. After printing a few sheets to test, the developer unit is loosing a lot of the developer, then a few prints later the dots disappear and K doesn't show up at all.
In the attached image, the page is speckled with black dots and you can faintly make out the text that should be black but it's white. So I'm guessing this means the image is making it to the drum. So I'm thinking I need to figure out what power supply to replace?

[Tecnico_Xerox]

Hello, you have a short circuit in the Black Development Unit. This is usually caused by a failure in the cylinder or the PWB that powers the cylinder. You will have to do tests to determine what it is before loading the developer, otherwise you will lose it again.

[adriansto]

Hello, you have a short circuit in the Black Development Unit. This is usually caused by a failure in the cylinder or the PWB that powers the cylinder. You will have to do tests to determine what it is before loading the developer, otherwise you will lose it again.

He already loose the developer material. Must check the bias electrical contact from back side of developer assy or the black bias hvps is faulty. On published print there is not white margins arround.

[stev0]

Hello, you have a short circuit in the Black Development Unit. This is usually caused by a failure in the cylinder or the PWB that powers the cylinder. You will have to do tests to determine what it is before loading the developer, otherwise you will lose it again.

Ah, would replacing the K developer housing unit be the first step to try to fix? We already tried changing the developer bias HVPS, which I think is what powers the developer unit? Unless there another power board I don't know about?

Thanks!

[Tecnico_Xerox]

Hello, you have a short circuit in the Black Development Unit. This is usually caused by a failure in the cylinder or the PWB that powers the cylinder. You will have to do tests to determine what it is before loading the developer, otherwise you will lose it again.

This generally happens when they remanufacture the cylinders and do not leave the circuit ground properly connected, causing the developer from the Development Unit to enter a short circuit and come out that way, similar to beach sand stuck on the sheet.

[stev0]

He already loose the developer material. Must check the bias electrical contact from back side of developer assy or the black bias hvps is faulty. On published print there is not white margins arround.

We did try changing the black developer bias HVPS, same result with the new one. Would replacing the developer assembly be a good next step?

[Tecnico_Xerox]

Ah, would replacing the K developer housing unit be the first step to try to fix? We already tried changing the developer bias HVPS, which I think is what powers the developer unit? Unless there another power board I don't know about?

Thanks!

There is another PWB, the one you need to check is the one that polarizes the cylinders, in this case the black one. But generally it is the cylinder that causes the problem, you could change it for another one and do tests.

[stev0]

There is another PWB, the one you need to check is the one that polarizes the cylinders, in this case the black one. But generally it is the cylinder that causes the problem, you could change it for another one and do tests.

Ok, is that other PWB located inside the K developer assembly? So if I just replace the whole developer assembly that would cover the bases?