Gestetner DSm622 - Solid Black Prints

[Jaxom]

And I do mean SOLID black.

I'm just kind of looking for suggestions of what it could be. I don't have the experience or training to just know what to look for.
I replaced the entire drum unit with a working 622 we have in the shop and it doesn't change anything, so I've eliminated that much.
Looking in the SP mode, I see that Vsg is .05 V instead of the 4.0 V, but, I'm not clear on what that means. I realize that VSG is Voltage Substrate Ground and is the bare drum voltage. I also assume this is directly related to my problem. But, if I take everything apart and clean it all out then VSG will go back up to 4.0 and the machine will print fine for about 20 pages, and then in the span of about 3 prints, it'll start to gray and then back to solid black.

I called Ricoh Tech Support, but all they could tell me is "it's a grounding problem" (how helpful), but I have continuity between the drum and the ground, soo ~shrug~.

Thanks in advance for any thoughts and suggestions.

[Jaxom]

Cleaned it up, and it printed great for 50+ pages, with a VSG of 3.98. Turned the machine off for about 2 minutes, turned it back on and VSG is back to .05 V, solid black prints, and SC 355 (ID Sensor error).

So, is it possible that it's the ID Sensor itself causing my problems?

[jonhiker]

I would say it is either the ID sensor, located on the transfer unit, or the high voltage board.

[Jaxom]

I would say it is either the ID sensor, located on the transfer unit, or the high voltage board.

Thanks.
I just switched out the ID sensor to no avail.
I'll test out the board next.
And of course, the board from the spare 622 has already fallen victim to parts cannibalism so I can't know for sure.

[Jomama46]

Black copy usually means there is no charge, so I would get a HV board and try it,

[Jaxom]

Still Black

Well, I replaced the board and still getting the solid black prints.

Take the drum out, reseat it. Works great. VSG is 4.0+/-.2
Until, I ran out of paper, 10 pages later. Put more paper in and it starts printing solid black again.

I'm pretty stumped on this and any suggestions would be greatly appreciated.

[Jomama46]

How about the charge receptacle. It plugs into the HV board and the other end has a spring that the pcu presses into. It may be grounding out to the frame. or the spring contact is bad or the harness itself is bad.
Also replace the powersupply board. It may be not supplying voltage all the time to the HV board.

[Jaxom]

How about the charge receptacle. It plugs into the HV board and the other end has a spring that the pcu presses into. It may be grounding out to the frame. or the spring contact is bad or the harness itself is bad.
Also replace the powersupply board. It may be not supplying voltage all the time to the HV board.

If this printer keeps working throughout Monday, you will be my new hero.
I've made about 100 prints so far since messing with the receptacle and all of them are perfect.

[Jomama46]

Somedays you pet the duck and somedays the duck bites back. Have a good week end.