Konica 6501 code 2421 and 3503

[galen]

I have a 6501 that give me am intermitent 2421 code. Manual say's yellow dev drive abnormality, TCR sensor, or PRCB. I have cleaned TCR sensor and another company just replaced the drum and transfer belt. Is there anything in the drive that needs cleaned or what have you guy's seen in the field? Also get intermittent 3503's and have replaced the two thermistors.

[Nor]

I have had the same problem (both on C6500 and C6501), C-2421 to C-2424, but mainly C-2421. I found turning the developing unit by hand three or four times solves the problem. I think that it is caused by the developer being slightly damp, consequently it is hard for the developer motor to turn. Interestingly, it occurs mainly after a weekend when the developer has a couple of days to consolidate. When the error occurs two or three times a week I have changed the developer, and that has solved the problem. Maybe because the yellow is the uppermost unit , it is more prone to humidity than the other developing units. I find that cleaning the dust proof filter/1 regularly, 2 or 3 times between PM's also reduces the problem.
I haven't had a problem with Error C-3503 so cannot offer advice.

[inutelkamo]

did you try changing the developer?

Or just reloading it..

If still error persist, change with new developer..

And btw, check the charging corona..

somethimes, this is cause by a burned charging chorona...

[greatahmed2001]

I change the developer but the problem still until now

[907tec]

This is going to sound odd, but make sure that the machine is properly configured for the paper you are using. If the paper is stiffer/thicker than the machine expects, the drums might slow down abnormally.


With that being said:

I had a persistent problem with 2421 codes last year on a cruise ship. I had swapped sensors, dev units, developer, 3 different types of drums, coronas, and sensors all without a fix. I eventually replaced the drum motor and shaft assembly, as well as the PRCB. It's an expensive thing to try, but it ended up working for us.

[aaurel1an]

I just had this issue and I solved it the following way:
Reset dev unit counter
Add 3 small spoons of toner
Activate automatic developer charge so it mixes toner and developer for like 1 minute
Toner density sensor initial adjustment

If you still get the error add more toner, repeat steps.

Also make sure charging corona is ok by replacing it with one from another color.


other things to do if still not working:
Manually rotate developer in the unit. Developer might be consolidated from humidity.
Check cables of the sensor
Check values of the sensors in service mode. Proper value is around 130.
Use state confirmation I/o mode 54-00 for yellow 03 for magenta. 06 for cyan and 09 for black to add toner to dev unit. Change these numbers by pressing access then the numbers.