For Status Codes, Diagnostic Simulations, etc... Intravia’s Guides:
1025 and 1038 are found in the 3rd Edition.

• Light Copies... Open the front cover. On the upper right is a knob and a button. Turning the knob will increase (or decrease) the toner dispensing during regular operation. If you press the button & close the front door (or cheat the interlock), the toner motor will run for a while and tone-up. If the copies are still light, look at the developer idler gear (smallest gear on the back of the DV unit). Often they acquire a hairline fracture which is frequently overlooked. Check the hopper for bridging and clumping of toner. Look for a foreign object over the toner dispensing hole (such as the seal from a toner bottle). Check the developer level. The level should be below 1/2 of the silver pipe inside. If not, the developer is preventing the toner from entering the system. Check that the inter-image lamp is clean (located at 2 o’clock on the drum). Look at the mag roller to see if developer is bunched on one side of the roller. Sometimes the stainless steel ground plate inside the DV Unit has come
• Light on one side of copy... Often caused by the machine not sitting level (from front to back). This can also be caused by an under-toned condition which tends to go light at the rear first. See the "Light Copies" Notes above for more info.
• U-1 Code "Main Drive Problem"... Mostly caused the gears on the motor binding on their shafts due to hardened grease. The gear stripping can be caused by almost any other parts in the gear train. Remove the main motor (in this machine, the main motor is located under the upper clamshell just before the fuser). Clean the shafts & gears throroughly and apply fresh grease. To check the fuser section for stiffness, make sure to "load" the fuser so as to imitate its condition with the clamshell closed. Check to see if the drive in the lower tray is stiff, often this turns out to be the culprit. Another possible source for this problem may be the Relay Board (which controls the Main Motor among other things).
• Intermittent Blanks... Often caused by Mag roller stopping. Usually the result of a failing Relay Board (found behind the main board if you’re looking at the back of the machine). May also be an arcing corona (any). Can also be caused by a wire to the developer drive motor having been pinched in the clamshell.
• Misfeeds... If the tires are turning but not feeding, replace them. Cleaning these has never worked for us on this particular model.