By Mike Josiah and the Technical Staff at Uninet
First released in June 2017, the Samsung ProXpress C301x/C306x series of color printers are based on a 31ppm, 600 x 900dpi engine (9600 x 600 Enhanced). The first page out is rated at under 9 seconds, and the monthly duty cycle is up to 60,000 pages.
There are both STD yield and High Yield cartridges available
CLT-K503S  Black 2,500 pages      $89.99*
CLT-K503L  Black 8,000 pages      $180.99*
CLT-C503S  Black 2,500 pages      $109.99*
CLT-C503L  Black 5,000 pages      $184.99*
CLT-M503S  Black 2,500 pages      $109.99*
CLT-M503L  Black 5,000 pages      $184.99*
CLT-Y503S  Black 2,500 pages      $109.99*
CLT-Y503L  Black 5,000 pages      $184.99*
* As of 11/1/2018
The printers that use this engine are listed below:
 Samsung ProXpress SL-C3010DW
Samsung ProXpress SL-C3010ND
Samsung ProXpress SL-C3060FR
Samsung ProXpress SL-C3060FW
Samsung ProXpress SL-C3060ND
Required Tools
1) Toner approved vacuum.
2) A small Common screw driver
3) A Phillips head screwdriver
4) Needle nose pliers
Required Supplies
Toner for use in the Samsung CLT-503 toner cartridge (Make sure you use the correct color and yield for you cartridge.)
Replacement chip (Make sure you use the correct color and yield for you cartridge.)
Replacement drum (Optional)
PCR (Optional)
Conductive Grease
Drum lubricating powder
Cotton swabs
Drum cover
1) With a spring hook, remove the springs on of both sides of the cartridge.
2) On the left side (non-contact) remove the 2 screws.
3) Press in on the two tabs and remove the end cap. Be careful! – Both halves can separate!
4) On contact side of the drum half, remove the two screws, press in on the tab and remove the end cap.
CAUTION! There is quite a bit of conductive grease on the axle!
5) Separate the two halves.
5) On the drum half of the cartridge, remove the drum.
6) Remove the two white PCR locks one from each side of the PCR.
7) Remove the PCR.
8) Remove the PCR cleaning roller.
9) Remove the two PCR holders pry up the holders by the locking tabs.
10) Remove 2 screws & wiper blade.
11) Clean out all waste toner. Make sure the wiper blade seals are clean!
12) Lubricate the wiper blade with your preferred system
13) Install the wiper blade and two screws.
14) Install the two PCR holders make sure the springs are engaged properly.
15) Clean and install the PCR cleaning roller.
16) Clean and install the PCR.
17) Install the two PCR locks
18) Clean, lubricate and install the drum. Long gear to the left (Enclosed) side.
19) Replace the chip on the drum axle end cap.
20) On the toner hopper, remove the three screws from the gear side end cap.
21) Press in on the two tabs and remove the end cap.
22) Remove the eight gears.
23) On the contact side, remove the 3 screws.
24) Press in on the two tabs, remove the end cap.
25) Remove the two small developer roller gears and place aside.
26) Remove the screw and inner end cap from the gear side of the cartridge.
27) Remove the Developer Roller.
28) Remove the Doctor blade and two screws.
29) Remove the fill plug on the lower half of the toner hopper.
30) Clean out all the remaining toner.
31) Install the Doctor Blade and two screws.
32) Install the developer roller.
33) Install the inner end cap and screw on the gear side.
34) Remove the fill plug from the upper half of the toner hopper and clean out any remaining toner.
36) Fill both the upper and lower chambers of the supply hopper with the appropriate amount of toner for use in the Samsung-CLT-503 cartridge. Use correct color toner for the cartridge.
37) Replace both of the Fill plugs check for leaks.
38) Install the two small developer roller gears
39) Install the eight gears as shown. Install all 7 white gears first.
40) Install the gear side end cap and three screws. Make sure the spring loaded arm is functioning properly.
41) Clean and replace the conductive grease on all the contacts. Install the contact side end cap and three screws.
42) Place then two halves together. Install the non-contact end cap and 2 screws.
43) On the drum axle end cap, clean and replace the conductive grease. Install the end cap and two screws.
44) Install the two springs (one on each side).
45) Install the drum cover.