Konica c500 What's wrong with magenta?

[henry finley]

This has been an ongoing problem for me, and I can't lick it. But I have to. Too far away from service people. It's a story of 45-20's, error 1's and error 2's, but it all leads back to the magenta. Here's the story. Copier starts with 45-20, so I have to disable that in 25 mode. Then I set up a document in Indesign with a full page magenta solid, and start the printing of about 100 copies. The first copies are very pale and sandy to touch. As it continues printing, magenta starts kicking in, very blotchy. As printing progresses, blotchyness gets better and better. After about 75 or so, it starts looking pretty good--good enough to go into 25 mode and re-enable the registration sensors and boot the machine ready for work. But if I don't get to work pretty quickly, the magenta starts going sour again, and another 45-20 is coming soon, I know it.
I've checked the appropriate sensors in 47 mode--all looks good. New developer, new drum, switched around the corona thingies--all that. The transfer belt looks just gorgeous, and I see no point in experimenting with buying another. Examined the developing unit--no stripped gears. All sensors clean, of course. No explanation or clue.
Automatic gamma adjustment says error 1, auto registration says error 2. And this whole thing traces back to the magenta offender. What do I do next? Please help, somebody. I'm desperate, and out of ideas.

[kalindd]

I think that you don't have proper bias on magenta dev unit or bad charge.
"sandy to touch" this means the you have developer on your print. There can be many causes for this to happen.
U can try swapping the magenta dev unit with cyan dev unit (put some tape over the hole so no different toner can make it to the other unit)
start machine and check, if when printing cyan( now it would appear magenta on print) print looks bad your dev unit is bad. You either need to replace it or repair it. If print looks good then problem is not in mag dev unit . Then print magenta ( now cyan unit) if print is bad even with cyan dev unit then the problem may be magenta charge or magenta bias.
Test those and post the results.
Good luck.

[henry finley]

I already tried that and learned a hard and bitter lesson--it immediately blew an ICP fuse on the PCRB. I don't think I'll try THAT again.

[henry finley]

I've made good progress at learning how to use the 47 mode, if someone can tell me what all to check. Thank you.

[Socialist]

Try so:
Check TCR sensor /M output value (in 47 mode code 50 multi code 13).
In 47 mode codes 54-00/54-03/54-06/и54-09 accordingly is a compulsory pumping of a toner in Y/M/C/K developing unit. After pressing of the button Start look at figures (these are indications of the gauge of concentration of a toner). Finish to 100-110 and press Stop. Normal value 125-130, 100-110 is the raised concentration of a toner. Carry out this procedure for all colours. Then check up humidity (a code 00-00). Should be not less than 30 if less - it is necessary to lift. Then execute Auto Gamma Adjustment from 36 modes (Process adjustment - Drum peculiarity adjustment - Automatic gamma adjustment) and look at values of voltage on colours. 450 - 550 norm, 650 - the top limit meaning that on this colour something is not perfectly in order.
If the Gamma adjustment passes normally roughness will leave.
Still there is a special firmware for С500/8050, preventing occurrence of errors of type 29-07/29-08/29-09/29-10 at low humidity

[henry finley]

Thank you. I'll do these checks, as much as it will allow. The items you mentioned in 36 mode are not possible. This problem results in an error 1 for the gamma adjustment at this time. As for low humidity--that CERTAINLY isn't the problem. This is NC in July, and there's no air conditioning. But I had this problem when it was cold too. I'm going to ask you to return to this thread. Remembering the 47 mode lets you check, but not change anything will leave me at another stopping point. Thank you, friend, for your help. I WILL return the kindness to another.

[henry finley]

OK--here's my result--I'm fairly happy with how things went according to your plan in 47 mode. Not at all happy with the voltages in 36 mode. Y==750-780, M==765-808, C==749-756, K--623-665 This was the drum potential stuff. The auto gamma voltages are 650 for the colors, and 411 for the black, with an error 1. I remember last week when I installed a new drum in the black, the error 1 quit for a time, so I tried experimenting with swapping that new one with the magenta. No good result came of it. I can't remember whether I swapped it back, but I have an idea I might just have to buy 3 more, but it still won't solve my problems. The count on this machine is about 800,000, I believe, but it was mostly befor I got it, so I don't know the history. I just wonder if throwing a whole bunch of money at it will change much. I've already done a developer change--that didn't help, in fact, it seems like I just made everything worse. Jeeze, I never was a boob before, but this machine is showing what a boob I might really be.
Try so:
Check TCR sensor /M output value (in 47 mode code 50 multi code 13).
In 47 mode codes 54-00/54-03/54-06/и54-09 accordingly is a compulsory pumping of a toner in Y/M/C/K developing unit. After pressing of the button Start look at figures (these are indications of the gauge of concentration of a toner). Finish to 100-110 and press Stop. Normal value 125-130, 100-110 is the raised concentration of a toner. Carry out this procedure for all colours. Then check up humidity (a code 00-00). Should be not less than 30 if less - it is necessary to lift. Then execute Auto Gamma Adjustment from 36 modes (Process adjustment - Drum peculiarity adjustment - Automatic gamma adjustment) and look at values of voltage on colours. 450 - 550 norm, 650 - the top limit meaning that on this colour something is not perfectly in order.
If the Gamma adjustment passes normally roughness will leave.
Still there is a special firmware for С500/8050, preventing occurrence of errors of type 29-07/29-08/29-09/29-10 at low humidity

[henry finley]

I did note a very slight improvement after doing what all you told me. Still had the error 1, still can't boot without diabling the 45-20 sensors. But when I ran my usual Indesign solid magenta page, the first one wasn't sandy. The magenta is still very blotchy and unusable, but it wasn't sandy. Still have to shut off the registration sensors to boot it, though. I'm afraid I have several problems going on at once, clouding the issue. Looks at the very least like a new magenta unit is in order, though since the only thing electric about it is the sensor screwed to the bottom. It's a natural magnetic roller, so I don't see what could really change with a new unit.

[RRodgers]

I did note a very slight improvement after doing what all you told me. Still had the error 1, still can't boot without diabling the 45-20 sensors. But when I ran my usual Indesign solid magenta page, the first one wasn't sandy. The magenta is still very blotchy and unusable, but it wasn't sandy. Still have to shut off the registration sensors to boot it, though. I'm afraid I have several problems going on at once, clouding the issue. Looks at the very least like a new magenta unit is in order, though since the only thing electric about it is the sensor screwed to the bottom. It's a natural magnetic roller, so I don't see what could really change with a new unit.

Have you pulled out the color reg assem and checked to make sure the sensor's are clean? On some of my boxes, sometimes I would get toner under the clear plastic covers that are on those sensors, so I'd have to take them apart and clean them.

Also, be sure that there are no void area's in any of the colors. Go into 36 mode and print out color pages for each one of the colors, use a setting of about 90~100. That should be light enought to show you any errors.

HTH

[henry finley]

Thank you for chiming in on this Mr. Rogers. I had already read your treatise on the sensor issue and already removed the unit and took it outside in the brightness to inspect it for trash inside with a magnifier. It's clean as a whistle. As far as the page printout in 36, I'm afraid I don't know how that is done. I have the manual, but some things aren't explained for dummies. I do know that 45-20 is getting worse, to where even shutting it off and printing out solid pages from Indesign to get the blotchyness out isn't helping any more. I can run some jobs, but with the sensors off, meaning this is no longer a high quality print machine.
As for you guys wondering--I'm the most attentive and willing pupil you'll ever know, just as a matter of respect. Thank you. PS--I'm getting more and more afraid of the PCRB on this. And I wish I better understood the transfer-belt story. Mine looks shiny and pretty, but that might not mean much. One bad piece of advice I got on here was to swap developing units--NEVER do that. Now I got a .75 amp Radio Shack glass fuse jury rigged on the PCRB for that lesson.

[henry finley]

I wish I knew how to get my hands on those special test sheets the servicemen have to put on the copy glass. This machine is NOT going to beat me. No machine ever has, and never will. You name it and I can fix it, even if I don't know what it does.

[kalindd]

I already tried that and learned a hard and bitter lesson--it immediately blew an ICP fuse on the PCRB. I don't think I'll try THAT again.
I'm sorry to hear that. I've done that in past and had no problems. But thanks for the input, I'll be more careful next time.
Something that comes out in my mind is, are you resetting the counters when replacing parts?
Also check this:
Description
SC45-20 at power up or while making copies.
Solution
PROBABLE CAUSES:
1. Color registration failure.
Perform the color correction calibration of the sensors PS8 and PS9 (p/n 4969-1729-01). To calibrate the sensors, perform the following:
a. Disable Color Registration Correction Control in the 25 mode, software dipswitch 25, bits 3 to 1 (ON) and bit 4 to 0 (OFF).
b. Run [Auto Color Registration Adjustment] in the 36 mode.
c. Enable Color Registration Control (software dipswitch 25, bits 3 to 0 (OFF) and bit 4 to 0 (OFF)).
d. Perform Auto Color Registration adjustment.
2. The shutter that covers the registration sensors PS8 or PS9 is not opening.
Clean the mechanism and ensure that the shutter functions correctly.
3. Color registration sensors have failed.
Replace the color registration unit (p\n 65AAR75800).
4. Failed PRCB.
Replace the PRCB (8050/CF5001 - p/n 65AA-9033 and bizhub PRO C500 -p/n 65AA-9035).
5. Stripped developer gearsor binding developing unit.
Note : When printing black and white prints, the black is missing on the page. Gradually the frequency of the voids increases and the SC45-20 is indicated
when the machine is powered ON.
Pull the transfer belt unit when the SC45-20 is indicated andobserve the CMYK pattern. If the K pattern is missing, then check the K developing unit (p/n1
65AA-972 2). Look for stripped developing gears (p/n 65AA 7721 0 orp/n 65AA 7722 0) and replace if necessary. If K developing unit is binding, replace the
assembly.
6. The toner level detection sensor located inside the corresponding color toner hopper will register a false full state. The sensor itself becomes caked with
toner.
Note : Developer will run completely out of toner even though all relevant systems are operating normally.
Open the toner hopper and clean the toner level detection sensor. This will allow the toner bottle to begin supplying the hopper with fresh toner.It maybe
necessaryto manually tone up the developer. This is accomplished by using the 47 mode.
a. First access the toner density sensor at switch 58 bit 0=yellow, bit 1=magenta, bit 2=cyan, bit 3=black.
b.Check the level, it should be between 150-180. Ifthe value is greater than 180,add toner to the developer.
c.To add toner to the developer, use switch 01 bit 1= yellow, bit 4=magenta, bit 7=cyan, bit 10=black.
d.Continue to add toner untilreaching the desired value.
e.When finished, cycle the machine power, then run some test copies to verify the correction ofthe problem.
7.Failed Transfer Belt Assembly.
Replace the Transfer Belt Assembly (p/n 65AA-261 0).
8.Imaging Unit not fully seated intoMFP causing a poor electrical connection and resulting in developer being depleted ( 8050/CF5001 only ).
Lubricate alignment pins on front right side of imaging unit. Replace developer.

[RRodgers]

I wish I knew how to get my hands on those special test sheets the servicemen have to put on the copy glass. This machine is NOT going to beat me. No machine ever has, and never will. You name it and I can fix it, even if I don't know what it does.

Uggg... I'll have to look it up for the exact wording in the machine but you can print out density tests in 36 mode. Just do it for each color. Set the other 3 at 0 and the one you wanna test at about 100 then switch to copy mode (make sure the machine is set to full color) and then hit start. It will give you out a nice half tone page. Do this for each of the colors OOOORRRR you can make the pages up in photoshop (or any program) to have the machine print out a nice half tone for each of the colors. I'd be willing to bet one of your colors is not printing out properly and that there is a void in it on the ends.

[henry finley]

Mr Rogers, I have a question regarding the construction of the registration unit mounting. It's held in by 2 screws at the back, of course, and just sits in a hook, or bracket at the front. But it's allowed to to move laterally to and fro in that bracket. It has a sort of shiny spring-stock metal behind it (at the front). But that spring stock (if that's what it is) seems to apply no pressure to force the registration unit closer to the transfer belt. In other words, the front end of the registration unit is allowed to just flop around laterally. I can push it closer to the belt at the front, but it will just find its own place again, which is neither to left (away from the belt) or to the right at the bracket stop (closer to the belt)
What is the story on this? Why would they construct it so as to just be able to slide laterally in that bracket? Where is the registration unit SUPPOSED to be? Thank you.

[henry finley]

And another thing--When I slide out the imaging unit and stand over the top of the transfer belt assembly and study it, it looks slightly twisted. There is a plastic thing about 3 inches wide across the top, which, being plastic, is not exactly the best material for "sighting" a straight line. But it DOES look twisted when I sight across it looking downward at the bottom of the assembly. When I take it out and lay it on the floor (on clean paper, of course), it lies apparently flat. But truth be known this is a very unstable assembly which can twist all sorts of ways just by handling by the carrying handle.
But I'd still like to know where the front end of that registration unit is supposed to be in the bracket--closer to the belt, or further away?
If I can get rid of that damn error 1 on the auto gamma adjustment, my magenta blotchy problem will straighten out--I've seen it happen before.
Mr. Rogers, as a professional, have I made progress in my learning, or do you think I'm a boob who should just quit, load the machine up in my truck and carry it to a serviceman in the city? Thanks, HTF

[henry finley]

I have been fiddling some more today and my magenta sandiness came back. I wonder if a new magenta developer unit would solve all this, simple as that?

[henry finley]

Is weather now my biggest problem? Now I've had a success. I hope somebody in-the-know reads this. Having only 1 brand new drum to work with, I took is from the black and put it in the magenta--switching charge assemblies too. Now I have a situation where all 3 colors are blotchy and unusable for professional work. Could it be because it's NC in July, and it's probably 90-some degrees in this room at 97% relative humidity? (according to weather website). ALL 3 colors are just about equally blotchy. As far as my 45-20, I now have the sensors on, and it hasn't been coming back since I bent a little bit on the shiny spring-steel thing behind the front of the registration unit. But I'm sure it'll be back. I haven't seen the last of 45-20, I'm sure. If I bought an air conditioner and put it in this room, would my blotchy problems start getting better?

I have been fiddling some more today and my magenta sandiness came back. I wonder if a new magenta developer unit would solve all this, simple as that?

[tech51]

Any one suggested the drum potential sensors yet? Ive had these give up in the past and cause gritty copies. I would try replacing it (may have to replace the dev as well).

[henry finley]

This machine is FINISHED. I'm TIRED of it. This 45-20 is dead-set stubborn. No matter what I do, there's no way of getting out of spending at least 2000 dollars on it. Thanks, friends. The end.

[RRodgers]

Wish ya lived closer. I'd go out and fix it.

[henry finley]

Wish ya lived closer. I'd go out and fix it.
Thank you for everything, Mr. Rogers. And I would respect you to do it. I went on EBAY and bought another one. I'll shove this one out on the deck and cover it up with plastic in case I buy a big boat and need an anchor.
Actually what I'll do is fiddle with it by swiping things off my good new one to try theories on the old one. Frankly PCRB is my first choice, and you can't substitute that, but possibly transfer belt assemblies can be switched. Anything that even changes the behavior without necessarily fixing it is a giant step. Could be just registration unit. Who knows without some spare parts? A tube caddy went a long way in making a professional TV repairman out of an ordinary boob. Pluck out a suspected tube, stick in a new one, and if the vertical hold stops rolling, it's fixed.
But this one is out the door--for sure. Thx, friend--HTF