MX-5500N Yellow issues

[OMD-227]

An update on this subject which might help someone in the future..............

Earlier today, I was sent to a Venus MX7001N with this exact same fault...... no yellow.
Everything else was working fine. Two junior guys had been onsite for quite a while, couldn't figure it out, and asked if I could go help out.

With 120 C-Dragon & Venus engine's in the field, and a large number of those pushing 750K - 1Mil or more, I was yet to see an issue with just the yellow missing, and everything else OK, without error code or unusual noise.

Of course I had seen and do regularly work on MX3500/4500N's with no yellow due to the transfer clutch or clutch shaft/main drive unit failure's, but was yet to see this on a C-Dragon or Venus. There is definitely no bulletin on this subject for this engine, only the Pastel1 & C-Jupiter1's.

A quick check of what they had done was OK. I performed a solid yellow page sim 64-01 and the image on the drum was great. All shutters, drums, devs, firmware, bias voltages etc etc all OK. With new Primary & secondary transfer belt units fitted only 85K ago, these were immediately dismissed as cause of the fault by the other guys.

I even remembered what Graybeard had said earlier about the secondary transfer charger housing block that was loose, but this one was OK (never had to remove that part anyway).

I was certain that this was a transfer issue, due to the fact the yellow drum had a nice solid page on it in sim testing.
By running sim 6-03 transfer load test, with the front cover lowered and front door switch tricked, you could just see that the yellow transfer roller was lowering onto the yellow drum OK, but the yellow follower/support roller (also within the transfer unit - beside the yellow transfer roller) was not lowering down all the way, therefore not fully pushing the belt onto the yellow drum surface.

The primary belt unit was removed and the cam assembly for driving the black & color transfer rollers within the belt unit downwards seemed to be alot tighter than normal, when driving it by hand. This seemed to explain why the yellow follower/support roller which lowers down last on a color page, was not fully dropping onto the yellow drum due to excess load.

A C-Dragon MX6200N on the same floor was temporarily 'raped & pilaged' of its primary transfer belt unit and the yellow immediately worked in the problem MX7001N.
A new primary transfer belt unit was fitted to the Venus and problem solved!

I remembered this post and wanted to update everyone with this issue to check the primary transfer belt (even if it looks good and appears to work fine!)


See some samples of before/after sim 64-01 halftone prints (sorry abou the detail... just 300dpi USB scans).

[Sharp Fixer]

the mx5500 family uses the MX700U1 belt and the mx5501 family of machine uses the MX701U1
the 2 units are similar but not identical
Had the same problem (loss of Yellow) appear after a day or 2 when i accidentally installed the wrong unit
a quick check of the service history confirmed the wrong unit. Installing the correct unit solved the problem.

[OMD-227]

I hear ya mate, but this was the right belt.

But......We have been using both belts in both machines perfectly fine for years now..... no problems. The parts breakdown list is basically the same. I know its wrong, but we dont have any problems using either belt unit. This was an actual hardware fault, not an incorrect part. As you can read in my above post, I put a transfer belt from a C-Dragon into a Venus, and it immediately fixed the no-yellow issue, as the yellow transfer roller & follower roller were being lowered correctly.

I would say that our C-Dragon and Venus machines have done several million pages now using the 'incorrect' transfer belt unit. Never had a problem. Its just like the Pastel & C-Jupiter belt units. They work perfectly fine when swapped around. You just need to put the heat-sink on the C-Jupiter belt unit cleaning assy if you are using a Pastel belt.

Its a beautiful thing when parts can be inter-changed and work perfectly fine. If you have a look at the parts list side-by-side, you usually only see one or two items that are different, and then its only by one number or FCZZ vs FCZ1 etc etc.

Just use what is available in your stock at the time.

PS... there is no such machine as the MX5501, but I know what you mean.