SC990

[Jomama46]

I ran into this yesterday and thought I might share this as a tip because SC990 has so many solutions.
This was a Gestetner DSm635. The first think I noticed was that the 990 was occuring at the end of a run, no matter what size. As this model makes a patch at the end of a run, I changed SP2208 to one to change it to pixel mode and prevent the patch from occurring. No more SC990.
Next I looked at the most likely culprit, I checked the values of SP2103-1 and -2. These are the current indications for the Laser Diodes, they should be low, on this model I think about 10 or 20. They were all the way up to 65. The laser was working too hard.
This told me that the door switches were loaded with toner.
It most likely was the ones on the upper right but I decided to cover all the bases and replace them all. The ones in the lower left are easy to get to but rarely have a problem, the ones in the upper right are a pain in the ass to change but sit within a few inches of the toner spray-o-matic system.
So I changed them all and problem solved.

[chip]

Ricoh Aficio 2035e also Gestetner DSm635. Ricoh RB135012....SC990 The following data is stored in the SC error log:
File: procon.c
Line: 8xxx (ex. 8573)
Value: 0
Note: In many such cases, SP2103-1 to -4 have been set to a value near the maximum (+64).

Cause : A normal Grayscale pattern was not detected 15 times consecutively during the ID sensor Grayscale pattern check

Action :
1. Clean the ID sensor and/or drum.
2. Replace the following, as deemed necessary:
�� OPC drum
�� Developer
�� Cleaning blade
�� Charge roller
�� Charge roller cleaning roller
�� LD unit
3. If any of the above actions resolved the SC, perform all of the following: 1. Execute SP3001-2 (ID Sensor Initial Setting). 2. Return SP2001-1 (Charge Roller Bias Adjustment) to its default value. 3. Return SP2103-1 to -4 (LD Power Adjustment) to their default values.
In pixelcount ID sensor is not used. Return sp2208 to 0 to avoid increase of maintenance. Then preform above actions.

Had the same problem !!!

[Fearless V K]

You guys don't see many of these machines do you? 99.9% of the time the SC990 is caused by a worn out drum. Replace it. These units want their drums at 150K!!!

By the way, I don't recommend leaving the machine in pixel count mode. It will run increasingly dirty copies if you do.

[pspahr]

By the way, I don't recommend leaving the machine in pixel count mode. It will run increasingly dirty copies if you do.

Fearless V K is right, drums at 150k and pixel count mode is evil if left unchecked.

[FRIDGEMAGNET]

My take on this (not sure if is correct) is that, as the drum wears out, the laser will need to increase its power to produce the same density patch (Vsp).
The laser has Auto Power Control in which it monitors the output from the laser with a photo diode, this is done when the machine is turned on and when the LD is on.
As the drum wears (120-150k) the power goes up SP 2103 1-4 gets to its maximum (64) and the system shuts down with SC990 and "File: procon.c Line: 8xxx (ex. 8573)" which I assume is a process control software problem.
None of this is helped by the crappy door switch situation.

[Jomama46]

I agree Fridge, Anything that will prevent the patch from being calculated correctly will result in a SC990. Usually the drum will present an obvious CQ problem that will signal replacement but the switches are not so obvious. Altho after all these years it should be!. I have a 645 we took in on trade that is running OK. The 3102 readings are at 59 and no codes. So They will have to be replaced during the rebuild.
I'm guessing that the LDDR could also cause this as it performs the temperature compensation for the LD current.
Toner is the enemy and must be controlled in our lifetime.

[saz_ryd]

Thanks for sharing the above info.

[neilt69]

SC 990

agree that its a process problem, a colleague encountered this problem which he tried to resolve with f/ware up/g and id sensor which did'nt work, tried to ask the drum life, quality of paper used, the toner if orig., dev. life. just recommend him to change consumables, reset to default the values of charge voltage, dev't. bias, then initialize td sensor followed by i.d. sensor, so many factors in process can show this problem almost all the possibilities and tips have been posted by chip, fridgemg, jomama46, pspahr, fearless vk, this just an addition for the said prob. it boils down mostly to the over used drums in rental basis machines.

[TonerMunkeh]

Just as an aside, the bastard-esque MP3500/4500 are killing their drums at around 120k now...

[Ollie1981]

Just as an aside, the bastard-esque MP3500/4500 are killing their drums at around 120k now...

Hehe, at least the drums last for that long.......as for the developer.........

20-90k

Mag Roller covered in a thick layer of crap

Overtoned/undertoned depending on which way it wants to crap out this week

Go back to the car, fetch your vac and forget any ideas you had that morning of going home in a clean shirt.


I have had sc990 that was caused by poor development on a machine in this model range, but that was immediately obvious from the copy quality.

My money is definately on a bad drum even if the CQ looks o.k.

[petrus]

I have this cases on A2045.after I change the drum C blade and dv Its run ok.
But when reach 70k its come back.sc990.is it cuold be the drum worned out?
I have try change Whole of the drum Assy and its gone.
But in this Drum usage, my customer not agree to pay for the bill.

[tech07]

sc990

Guys I was having the same problem w/ a Toshiba 901 (ricoh mp9000) constantly. I do agree with all of your analays. But I fixed min by downloading a new firmware update. It went to happening 3 or 4 times aweek to never.. Just a thought

[Jomama46]

I have this cases on A2045.after I change the drum C blade and dv Its run ok.
But when reach 70k its come back.sc990.is it cuold be the drum worned out?
I have try change Whole of the drum Assy and its gone.
But in this Drum usage, my customer not agree to pay for the bill.

If the machine does not have adequate ventilation or the room is too small, then the drum will not make it to 150k. I have one account where the drum will only go about 80k and then 990 out until I replace the drum. It is in a large closet and even tho they have a de-humidifier in there, it just isnt enough. At one point I had the 2045 moved to another room out in the open and it did much better but as they were so much smarter than me they moved it back into the closet and they are back buying drums early.
Aint my problem.

[SGT_Snacks-64]

Being new to the industry, I work on more of the lower volume machine, especially the Adonis/(35/45 BW CPM) range. Out in the field recently I've noticed an increased case of Medakka on the MP3500/MP4500 drums, I've never seen it on any of this range's older brothers. These machines are in open offices, I'm wondering if there could be a ventelation problem "what with the amount of toner the damn thing kicks around!!!!"

As for the Developer problem. When I get background/Half Background problems "Which is normally happens when you so much as breathe on the drum!!". Vac the entire machine, take the toner out, clean the Mag Roller while trying to keep as much Dev from it as possible. Reassemble the machine without toner, run about 100 half Sky Shots to detone the dev, replace the Toner and have found that to work.... in most cases.

It's simply hit or miss..... or the wrong dev being installed previously! :O