C350 P codes and no image - HELP!!

[ep@ethos]

Hi, I am having real trouble with a C350. Initially poor black solids but no P codes, looked like poor bias. Checked HV board and since doing so I have lost all image and now shows various combinations of P6,7,8 and 9 intemittently. Have double checked wiring and replaced HV and PWB MC to no effect. There is some toner on the edge of the page but this feels rough and is not fused.

Any help greatly appreciated.

Thanks.

[mtech]

Is there any image on the primary transfer belt? Which HV PWB did you replace? There are two HV PWB,s one is for transfer(located lower right under LED assy.) The other is for the drum units. I had a C350 with no transfer and it was the HV board under the LED assy. Pain in the neck to replace. Also check the ICP's on the SYS board.(The ICP's are tiny little circuit protectors like fuses that are soldered to the PWB) The SYS is a rather large PWB with practically nothing on it, located on the upper right side. If one is blown you get wacky issues. Seen this twice.

[ep@ethos]

hi mtech, I have replaced the HV board at the back above the IU drive motors. there is no image on the transfer belt. Also replaced the large board at the back with the ICP's (PWB MC, is this the same as the SYS board you mention?)

[B0265]

We have had ta similar problem once, had to replace the PWB MC and all 4 IU's.
There is a modified PWB MC (don't have the part no at the moment) with higher ratings of the fuses.

[mtech]

The pwb-mc is what I was referring to as the SYS board. I remember that the problem I was having was no secondary transfer and it was HV unit 2. You said your getting no image on the primary belt so your issue is different. I found a nice tech bulletin in my files that I think will really help you with your issue. I attached the file and also a diagram with both hv pwb locations. You said you replaced hv 1 and the pwb-mc. Did you replace them as a set? If you replaced pwb-mc first, there is a chance that a bad hv 1 could have blown an ICP on the new mc-pwb. The attached file mentions two of the ICP,s but remember the pwb-mc has a bunch of them. Hpoe this info. helps.

Regards

[ep@ethos]

Thanks guys, I did replace HV1 and PWB MC together but made no difference. The fault was sudden after checking connections on HV1 for poor solids on black unit but other colour were ok and copies were otherwise good. Sure must be a connection somewhere I have missed. Will check further tomorrow and let you know how I get on.

[mtech]

Good luck. After you get things back try changing the black image unit if black solids are still light. I have found that usually if it is just one color having a problem it is almost always the image cartridge. Even if it was just put in. If the cartridge was stored improperly it can be ruined. Thats why the boxes are shaped so weird.