C-2557 caused by a filter

I had a worrying call about a Bizhub 362 that was getting C-2557 errors. A C-2557 error on a Konica Minolta copier is caused by the Toner Concentration Ratio (TCR) sensor in the black developer developer unit reading too high. The TCR sensor reads how much toner is in the developing unit and allows the machine to control the toner level by adding toner. But if the level is too high the copier can't easily remove the toner from the developer mix and so an error is generated. Sometimes the high reading is actually caused by too much toner in the developing unit but usually by old developer mix or a faulty sensor causing a bad reading.
However the machine I am looking at doesn't have any of those things wrong with it. How do I know? Because I changed the developing unit only a month ago. Also the error only occurs during longish print runs (50 pages) and if the machine is allowed to sit for a few minutes and turned off and on again it will work fine until another long print run is started.
I went into the service menu and had a look at the TCR sensor values and they seemed normal and then did an F8 just to be sure. No good.
While waiting for the F8 to finish I went and had a look at the Konica tech bulletins for this model and found an interesting bulletin all about this very problem. The Konica boffins mention that if the ozone filter is blocked it can cause the error. So I pulled the back off the machine and pulled the filter out and sure enough it was full of dust. I vacuumed it out and the other filters while I was in there and put the machine back together. I gave it a test and no more errors!
It seems that the restricted air flow through the filter was causing the imaging unit to overheat during longer prints and then the TCR sensor would start giving higher readings until it failed.
So just because the filters are hard to get to doesn't mean that you should ignore them. Clean your filters!

C-2255 after IU replacememt

I had a slight problem after changing the colour imaging units (IU) in a Bizhub C754e. The 3 IU had reached the end of their lives so I pulled them out and put a new set in. The machine then displayed that an internal error had occurred and rebooted itself twice. Still failing the machine displayed a C-2255 error and gave up. I pulled up my list of trouble codes for these machines on my phone and had a look but this code was not on this list!

Don't panic yet.

I have a list of trouble codes for the C364e on my phone as well and the code is there. Developing unit motor failing to turn. Obviously one of the new imaging units had a problem with its developing unit that was causing the drive to lock up. Not the first time I had seen this so still no need to panic.

I started from the left and pulled the yellow IU and used my pliers to give the developing drive coupling a turn clockwise on the back of the IU. It was jammed.

Sometimes the developing powder in the unit can settle in transport and jam the augers inside the unit. Giving the unit a few taps on the side while turning the coupling quickly freed it up and I stuck the unit back in. I pulled the other two out but they felt ok and went straight back into the machine. I then went through the gradation adjustments without any more problems.

I will point out though that if you have this problem you need to be careful not to shake up or spill any developer out of the new unit as you will not be able to use it and it will need to be replaced. Also be careful not to turn the coupling to hard or it can break. But don't worry if you do as you have a spare on the old imaging unit that you just took out. And always turn the dev unit drive in the correct direction.

Also someone had played around with the date on this copier so now it shows the image unit life counter start dates as being in 2012. Not a problem but may confuse the next tech who comes to look at it and will wonder why the image units were changed 3 years before the machine was even manufactured.

Blank page removal not working

I was given a quick fix for a scanner problem just now that is interesting. There is a feature on most copiers called blank page removal. While most users have never heard of it it is pretty obvious. When copying or scanning if the machine detects that a page has nothing on it (a blank page) then the machine has the option to remove that page to save paper or scanned file size.

Why would you copy a blank page? Double sided scanning mostely. If you scan two sheets that contain three pages so the last side is blank then you don't want a PDF file with a fourth blank image. Selecting blank page removal solves this. 

However we have a had a couple of machines with DF-701 dual scan document feeders that won't do this blank page removal. The DF-701 has a Contact Image Scanner built in so it can scan the back side of the page at the same time that the front side is scanned and thus doubling scanning speeds. However some of these CIS units don't calibrate correctly and pick up a shadow on all pages and reports that the page is not blank. The shadow does not show on any scans or copies but prevents the bank page removal from working.

I am sure a firmware update will come along to fix this but until then I was given a work around. If you go into the service mode and turn off CIS calibration under system 2 then the blank page removal will work fine. Just remember to turn the copier off and on after changing the setting.

Original left on glass part 2

Not long after my last post about dirt on the scanner glass causing the copier to constantly detect A3 size paper on the glass I got a call about a machine constantly detecting A4 on the glass. The machine is a Bizhub C364e that I had recently replaced a board in and the problem had occurred repeatedly since that repair. 

Since the last thing to happen to the copier was the board replacement I first had another look at that board to see if a connector was loose. I pulled the copier out away from the wall and took the rear covers off to have a look but found nothing wrong. I tested the copier before putting it back together and could no longer get it to detect A4 when there wasn't one on the glass. Yay, fixed. I put the covers back on and pushed it back into place and tested it again and the problem was back. Hmmmm.

As in my previous post the copier looks for an original on the glass when the ADF is lowered. With the last problem it was the original length sensor that was detecting something that wasn't there. This machine was using the scanner CCD to detect something that isn't there. Testing different combinations of A4, A4R and A3  showed me that the problem was towards the front of the scanner because it couldn't tell the difference between A4 and A4R. The copier was seeing something at the front of the glass that it was interpreting as an A4 length piece of paper.

The problem only occurs when the machine is against the wall so I pulled it out away from the wall and tried again. No problem. I have an idea. I look at the carpet for divots left by the copiers castors and found none. This is really nice carpet and the machine has not left a mark on it since it was installed. This also means that I don't know where the machine was exactly positioned when installed. Aha!

When I had the original problem I moved the machine back against the wall and a little to the right away from a shredder that was there. I thought it was a little close and there was space for it to be moved so I did. When I pushed the copier back 10cm to the left closer to the shredder the original detection problem went away. So the position of the copier was causing the problem. Why?

With the copier 10cm to the right the scanner mirrors are directly underneath a set of ceiling lights and when the ADF is lowered the scanner "sees" the light and is interpreting it as light reflected off a piece of paper. A few cm in any direction puts the mirrors out from under the light and the scanner cannot see it.

So remember: Position, Position, Position! If the scanner is detecting something that isn't there try moving the copier a little.

Original left on glass

Today I went to a call for a Bizhub C754e that was constantly complaining that an original had been left on the glass and was not allowing users to copy or scan until it had been removed. However nothing was on the glass to be removed. This is not the first time I had seen this.
Switching the machine off and on again would allow users to use the copy and scan options if the document feeder was used until the document feeder (ADF) was lifted and an original placed on the glass. The problem can be replicated by simply lifting the ADF and closing it without putting an original on the glass. The detected original on the glass was always A3. The fault: dirty or streaky glass.
When the ADF is lowered it activates a switch at the back which triggers the scanners original detection. You can see this as the scanner lamp coming on when the ADF is still raised about 20 degrees. The reason the lamp comes on is because the machine is using the scanner to look for the width of an original. It is done before closing to get the contrast of the paper against the open platen cover. But this isn't the problem area.
At the other end of the scanner bed is one or more sensors that are used to detect the originals length. This is what detects the difference between A4 and A3. It consists of an infrared LED and a detector. Infrared light is shone up at the original and if an original is present will be reflected back at the detector. This can be tested in Sensor Check under State Confirmation in Service Mode.
But if there is no original what is the sensor detecting?
The first time I saw this was in an office where the copier was located near a kitchen. It seems that someone in the office took it on themselves to clean the scanner glass and used the conveniently located dishwashing soap to do it. The soap left a film on the glass that looked clean but was refelecting the infrared light back to the sensor. I gave the glass a good polish with a dry cloth and the problem went away.
However today's machine is not located near a kitchen nor had anyone owned up to cleaning it recently. But after giving it a good clean and polish the machine started working again.
Another thing to keep in mind is that we have had problems with a copier that would have this problem only late in the day. About 4pm this problem would happen but the next morning it would be fine. After arranging to have a tech arrive after 4pm it quickly became clear that the machine was near a window and the afternoon sun would shine through into the scanner. It was the sun light messing with the original length sensor and of course the next morning the sun would be shining from a different direction. That was easily fixed by closing the curtain.

Bizhub C35 miss feeding

Once again I got a call to fix a jammed Bizhub C35 that the customer could not find the jam. The simple answer to this is that the machine has not jammed. If the user had actually read the screen they would see that the message on the screen says that there has been a miss feed in the tray and can the user check the paper in the tray then open and close the right hand side door. It does not say the word "Jam" anywhere.
The problem occurs when the machine tries to feed the paper during printing but is unable to pick up the sheet from the tray and hence a miss feed. Since no paper actually moved from the tray there is no jam but the error message on the screen looks similar to that of a jam with the message to open and close the right hand side door. The reason to open and close the door is that this is the way that the machines controller clears the error message from memory. However, since it looks like a jam screen most users expect to find a sheet of paper inside the right hand side door and believe that the machine is broken because there is none.
So for these cases I explain that if there is a miss feed displayed on the screen then they need to check the paper loaded in the tray and this is most likely what they will find:

The most common cause is that a sheet of paper is sticking out to the right from somewhere in the middle of the stack of paper. The part that sticks out folds up along the inside of the tray. As the top sheets are fed into the machine the stack decreases until the sticking out sheet gets between the top sheet and the feed roller. I don't know how this happens but it has happened many, many times.

Since the feed roller is mounted to the paper tray it is easy to test the feed by turning the roller by hand. If the paper doesn't feed check that the top sheet is touching the roller. If it is check for the sticking out sheet in the middle of the stack.

P.S. I just had this same problem on an Okifax F-305 so it is not just the Konica machines that do this. The Oki also made a loud shuddering noise as the feed roller skipped across the top of the paper.

Tray 3 horizontal transport jams

I have a Bizhub C654e with jamming in the tray 3 horizontal transport unit (J-1730). 

The C654e and C754e or their black and white counterparts have large capacity trays for the bottom two trays. Tray 3 can hold 1500 sheets of 80gsm and tray 4 1000. The trays are position side by side with tray 3 on the left so to get paper from tray 3 to the vertical feed path on the right of the machine a hozontal transport unit is fitted above tray 4. This is why tray 4 is smaller.

J-1730 jams in this horizontal transport unit are just the same as jams at the vertical feed and mean that while paper pick-up was good there was a problem with the paper feed or separation rollers. So first thing is to change the worn looking feed and separation rollers. Easy.

Still jamming.

When removing the jammed paper I can see that the paper has not yet entered the horizontal transport unit so the problem must be in the feed station. There are a set of horizontal feed rollers in the feed station itself so I pull the cover off to have a look but didn't find anything suspicious. While the cover was off I removed the feed sensor actuator to have a look to see if the sensor was dusty. This is what I found:

If you look at the face of the actuator you can see a groove cut into it at about the same height that the paper would hit it. 

I had a look at the paper that had jammed and could see marks on the edge at the position of the sensor. Next I manually feed paper into the sensor to see if it would catch on the groove. Yes it does.

It seems that paper hitting the actuator at the exact same spot 200 thousand odd times had worn a groove that was causing the jams. Strange that I had not seen this before. But I had never looked for this before either. I will now.

I sanded and polished the face of the actuator and ran some paper through the machine from tray 3 and could no longer get it to jam so I will definitely need to remember this.

A cockroach on the laser

I got a call to fix a Bizhub C364e that was reported to not be printing all of the text on documents. When I arrived I was shown samples of some black and white documents with voids at diferent locations on the pages. So to start with I printed out the C, M, Y, K gradation test prints and this is what I got:

The magenta print was from the first try. I had no idea what caused the marks so I pulled the drum out and had look at the charge unit but didn't see anything so I shone my torch into the machine to have a look at the developer unit. I couldn't see anything on the mag roller but am sure I saw a shadow move under the cyan unit. After a bit more looking I didn't see anything so tried the gradation prints again. This time the colours were fine but I had a void through the black as seen in the above picture. So I am thinking what the hell could cause a void to move from one image unit to another?

I pulled the black drum out and shone my torch into the machine and again saw something move over the laser glass and disappear under the drum mounting rail. So I got down lower and looked into the hole for the laser glass cleaning wand and got face to face with a medium size cockroach. It was sitting on top of the laser unit and seemed to be dazed. My guess is that it was walking back and forth across the laser unit occasionally blocking the path of the lasers and causing the voids in the prints. The dazed look was probably because the roach had been blinded by the lasers. 

As I watched it crawled right and up toward the registration rollers. I had to get it out because I didn't want it to make a mess on the laser glasses or worse. What would happen if it got into the high voltage supply behind the image units? 

Since I last saw the roach heading toward the rego rollers I opened the right hand door of the machine and was sure I saw something disappear into the tray 1 feed station so I pulled all that out. Nothing there. So I pulled the registration assembly out. Still nothing. So it must still be on the laser unit so I pull all the drums, developer units and image transfer belt out but I still can't see it. Next out comes the power supply and then the laser assembly.

I look into the now hollow machine and see no sign of the cockroach. 

I look down at the laser unit in my hands and can see a leg poking out from underneath the end of the laser unit. I carefully tip the laser onto its side and the cockroach immediately runs and hides in a small hollow space next to one of the skew adjustment motors. Aha, cornered.

At this point I think I should mention that I have an irrational fear of anything with more than four legs. Insects really creep me out, spiders are worse and the bigger they are the easier it is see how freaky looking they are. So being this close to a decent size cockroach is really getting my heart pounding. But this copier must be fixed!

So I stick my screwdriver into the hole and flick the cockroach out. It went nuts on the floor trying to find a place to hide and I dropped the laser unit and both tried to jump on the cockroach while at the same time jump away from it. Unfortunately with all the parts I had pulled off the photocopier spread around the floor around me the cockroach had many places to hide. 

So there I am in the middle of this office shoving copier parts aside with one foot and stamping the floor trying to end this cockroach. I am sure I didn't impress any of the girls working there. But I did get the cockroach.

After that I put the copier back together again and everything works as it should. 

I am just glad it wasn't a big Huntsman spider in there or I would have had to call another tech to come and get it out. Either that or write off the machine.

Tape on toner cartridge

This is quick but it made me laugh. I was working on a photocopier and noticed a used toner cartridge on the floor next to the machine waiting for the cleaner to hopefully pick it up. What got my attention though was the packing tape was still covering the shutter on the cartridge.

So the toner had been taken out if it's box and jammed into the machine without the user spotting this tape. Amazingly the tape tore and stretched to allow the shutter to open and the machine to work. If it didn't I am sure I would have been called to fix it.

An Unknown error

Yesterday I got asked help with a Bizhub C754e that had some scanner problems. Most mornings the machine would have a C-9401 error when first used. According to the manual C-9401:

While this seems to indicate that the exposure lamp is the fault I was asked to change the CCD first. We didn't have a new CCD in stock but we did have a Bizhub C654e that was being stripped for parts that I could take the CCD out of. 

I went out to the C754e first thing in the morning to find the scanner had been locked out and the history showed that the C-9401 error had caused this. The actual swapping of the CCD was straight forward as was getting it lined up.

However when I powered up the mc I was given a C-D291 error. When I looked up the code in the manual I found an entry for the code but the only description there was "Unknown". What does that mean?

I knew that it was most likely caused by the CCD so I checked that all the cables were seated correctly but that was ok. The only thing that I could think that was different between this CCD and the original was the firmware. The manual never mentioned updating the firmware when installing the new CCD but the manual also doesn't mention anything about using a 2nd hand CCD either. 

The machine already had the latest firmware loaded on it as did the machine I took the CCD out of but I loaded up this firmware again, rebooted the machine and now it works.

So if you have a C-D291 error or other unknown error try reloading the firmware, you might get lucky. Also changing the CCD fixes the C-9401 error.

Power cord instructions

I had a comment on my IH power supply post about what power cords are used on these machines so here is page from the installation instructions which may help.

Paper behind the trays

At least once per week we will get calls about a copier that has an error after a jam with a code C-0202, C-0204, C-0206 or C-0208. These codes will be displayed on a bright red screen that states that one of the paper trays can no longer be used. The message continues to ask if the user wishes to continue to press a "Continue" button on the screen then prompt the user to turn off then on the sub power switch which is on the control panel. If this is done as instructed the copier will work as normal except the affected paper tray will no longer be selectable. Usually the user will panic at seeing a scary red screen and call us or will fail to read the on screen instructions and turn the copier off and on at the main switch and will have the error again once the machine starts up.
The C-020x errors are common to all Konica Minolta Bizhub copiers and printers. The code refers to the paper tray lift motor malfunction and the last number refers to which particular tray is affected, 2 for tray 1, 4 for tray 2, 6 for tray 3 and 8 for tray 4. The error occurs when tray has been pushed into the machine and then engages the motor behind the tray that lifts the paper into the feed rollers above but the paper does not reach the upper limit sensor within a set period of time. If the machine tries to lift the paper in the tray but waits for a longer than reasonable time for either sensor that shows that the paper is at the correct height or the sensor that shows the tray is empty then the machine presumes something is wrong and stops.
While I have had a couple of lifting motor gearbox couplings fail in the last few years and once had an upper limit sensor fail these are fairly rare. Just about every time I see these errors it is because of a sheet of paper getting behind the tray and preventing the lift gearbox coupling with the lifting plate in the tray. The paper usually gets behind the tray if there is a miss-feed from the tray and the sheet ends up between the feed and separation rollers and the tray is then pulled out and the stuck sheet stays in the machine and falls behind the tray. When the tray is then pushed back in the sheet is pushed into the lift motor. To prevent this the on-screen instructions for clearing the jam and the instructions in the user manual both state that before pulling out the tray the lower right hand side door should be opened and any paper pulled out. But not many users read the instructions.
Removing paper from behind the tray is not as easy as it sounds even if know it is there. This is because of the group of switches behind each tray that detects the position of the guides in the tray to automatically detect the size of the loaded paper. To prevent accidental damage to these switches by people reaching into the machine the designers of the machines added brackets at the front to prevent the trays from being removed. The brackets are in different places on different models or even on different trays but are easy to spot if you know what you are looking for.
Once the paper is removed opening and closing the front door of the machine will clear the error code or if the tray has been locked out then switching the machine off and on at the main switch will allow the tray to be used again. After the tray can be used again the cause of the original jam should be investigated to prevent the chance of the same error happening again.
So the lesson is if you have a jam always check for paper in the right hand side of the machine before pulling the trays out.

Jamming at the horizontal transport unit exit

I am running up a new Bizhub C754e today with a FS-534 finisher and I am reminded of some problems with paper jams that I have had with this combination.
The first time we had trouble was with a customer who was an hour and a half drive away and was reporting "Jamming everywhere in the copier". Jamming everywhere usually means a jam in the finisher or towards the end of the paper path. Larger printers have multiple sheets of paper running through them at once to keep the time between prints as short as possible. A jam like this means that there is paper all through the machine when the jam occures and they all need to be removed before the machine will work again. This is described by normal people as jamming everywhere. In fact it is only jamming in the finisher.

I wasn't the first tech to have a look at the problem but the guy who was did a lot of testing but couldn't get it to jam. A couple of days later another call came in for the same problem so I went to have a look. All photocopiers keep a log of the latest jams including a code that describes where the jam occurred, the time, date and what paper was being used. When I looked at the log all I could see were document feeder jams. So I cleaned the ADF and replaced the feed rollers and then gave the machine a good test.

Since it was a decent drive to the office where the machine was located I really wanted to make sure that the problem was fixed but I had doubts. I was worried that we are missing something with jams not being logged so I turned on the option for the machine to display jam codes. Normally when there is a jam the machine will display a picture showing where paper needs to be removed from the machine but no information about what caused the jam. Now when there is a jam a code will be displayed on the screen. I asked the girl at reception if she could keep a manual log of any codes if the machine jams so we could have a better chance of fixing it.

Sure enough a couple of days later we got a call that the jamming had not stopped. I was surprised when I arrived that the receptionist had not only taken note of the lack of jam codes displayed but had used her phone to take pictures of the paper jammed in the machine before it was cleared. I was interested to see that not only wasn't the machine logging jam codes but won't display them either. The pictures though showed clearly that the front corner of the paper was catching at the finisher entrance. 

It didn't take too long after looking at the pictures that there was a groove cut into the plastic lower guide at the exit of the horizontal transport unit. 

The lower guide is removable (3 screws) and has a series of ridges that look like they are there to reduce the friction of the paper sliding over the plastic. However with the C754/FS-534 combo the edge of an A4 sheet lines up perfectly with the inside edge of the front most ridge. After a 200000 pages or so have gone through the paper actually cuts the plastic an causes a groove on the inside of this ridge. This causes the jamming.

To fix the problem we replaced this guide with a new one but that only fixed the problem for another 200000 pages and the jamming started again. So a final fix was to use a sharp knife to remove the bridge and then polish the plastic to smooth it out completely.

So the lesson here is to not always believe the logs.

Customers annoyed that I am fixing their copier?

I just had a job to do a periodic black drum replacement on a Bizhub C552. This was an automated call so the customer did not call us but should have known we were coming because there was a message on the copiers screen. Replacing the drum hardware only takes less than 5 minutes and then I would need another 5 minutes to perform gradations and stabilisation adjustments. 

Before I could finish replacing the drum I had a guy looking over my shoulder to see where his printing was. Since I don't turn the machine off while doing this procedure the print job was in the queue so I quickly shut the machine to allow his print job to complete while replacing the filters in the back of the machine.

Since there are no more jobs in the queue I switched to service mode to do the calibrations. The gradation adjustments involve printing a pattern of gradation bars and placing the print on the scanner to allow the mc to analyse them. The first page worked fine but the second failed. I started the sequence again but while printing a girl came over and grabbed the gradation sheet from the output tray thinking it was her print job. She took one look at the coloured bars on the page, gave an annoyed grunt and then asked if the printer was working. 

She had to walk around me, a stranger to this office, step over my open tool bag but only thought to ask if the machine was working after she had grabbed my printing? Clearly not the brightest and unfortunately not the only unobservant person in this office. During the following problems I stopped what I was doing several times to allow printing but was constantly getting questions about when the machine can be used by annoyed looking staff. My reply was, as always, to smile and say that they can print but may need to wait a minute to collect their jobs. The responses were universally grunts or moans.

The problem I had was that I was printing the gradation patterns on A4 paper and the copier was not accepting the first pattern but gave no explanation. The pattern looked ok to me so I first cleaned the scanner optics (pausing for print jobs) and tried again but failed. So I next cleaned the IDC sensors, performed initialisation and stabilisation and tried again but still failed. So while pausing again for any print jobs I had a look at the gradation prints and noticed that the patterns were evenly centred on the pages. Normally they are closer to the bottom of the page. Hmmmm.

The machine normally takes its paper from trays 1 and 2 for gradation prints so I pulled them out as well as tray 3 which had pre-printed letterhead loaded in it and tried again. I wanted one of the lower trays as they are large capacity trays that are only for A4 and therefore have their guides fixed to the machine and so there will be less centring issues. Sure enough the gradations worked.

So the problem was with either tray 1 or tray 2 not being centred. These trays can hold several sizes of paper by having their guides opened or narrowed to suit. The guides can also be moved forward and back in the machine to adjust the centring of the paper by loosening two screws and then adjusting them. A notch on the metal base plate lines up with a scale on the plastic tray to give an indication of where the centring currently is. On this machine both trays were currently pushed all the way to the rear off the scale. Gouge marks in the plastic around the fastening screws showed that the guides had been forced to the back without loosening the screws so my guess is that someone had tried to open the guides without releasing them first and this caused the centring to change.

Easily fixed.

While not being able to complete the gradations or the centring problem with trays 1 and 2 were not critical problems and probably not noticeable to most of the people on this office it would have been nice to fix them without all the negative comments and noises. I am just trying to help.

IH power supply failure

I was having lunch at the office when a call came in for a Bizhub 552 that had stopped working and was displaying an error code. The customer was good enough to read us the code which was C-3B07. I knew from memory that codes starting with 3B are problems with the inductive heating system in the fuser. These codes have stuck in my memory as I have had a couple of difficult jobs that started with these codes.

We had a look at the service manual and confirmed that C-3B07 is the IH power supply reading a low input voltage. While the service manual tells us to check the supply voltage, fuser and heating coils first we know from experience to skip all these and go straight for the IH power supply board itself. 

Do we have the part? A look in the parts manual for the part number and then a check of the inventory shows us that we don't. What we do have is a couple of C552 colour copiers that I can pull parts off. While the 552 is the same as a C552 except for the lack of colour imaging units I wanted to check that the power supply was the same but my boss said not to worry about it. "Of course it will be the same". So I grabbed the board and headed out.

First I reset the error and then restarted the machine and as soon as it tried to print the error came up again. That's good because I hate intermittent faults.

It only took me 15 minutes to change the power supply and start the machine up again but then another error comes up! C-3B02 this time. A look in the manual says that this error occurs if an incorrect IH power supply board has been installed in the machine or by a general CPU error.

The first thing that comes to mind is that I have the wrong board. I am thinking that no, a C552 IH power supply does not fit a 552. I am about to call my boss and let him know that he has stuffed up but decide to compare the part manuals for the two machines first. Interestingly my boss was right and the board is the same  for both machines.

 So why the error? I know the IH power supply worked in the C552 at the office so why won't it work now? It is the right part for this machine so the first part of the error description in the service manual is wrong. That leaves the general IH power supply CPU error. The printer control board in the back of the machine cannot talk to the control chip on the IH power supply board. 

Since I know the board worked before I touched it then my next thought is that I caused this fault. How? The obvious answer is that I forgot to plug a connector in.

I pull the covers off and have a look. The connector for the wiring that runs from the printer control board to the IH power supply looks good as do the coil terminals. But the input power connector? I forgot that completely. My only excuse is that it is at the bottom of the board while all the others are close to the top. However the connector I missed is three times the size of the others and has some heavy gauge wire so it is normally hard to miss. 

Once that is fixed I check the other connectors again, put the covers on and power up the machine. It works great.

Careful with mylars

Here is a very common cause of jams in Automatic Document Feeders (ADF). All ADFs that I have seen from all manufactures have sheets of plastic called mylar stuck in the paper path to help guide paper over various rollers. These mylar sheets may be completely stuck down but mostly are glued down at the front edge and the trailing edge flaps loosely usually ending at the leading edge of a roller. The engineers who designed the copiers add these to to prevent the leading edge of the paper from running into the side of the roller and buckling against the roller instead of smoothly running over top of the roller.

However, sometimes the ADF jams and the user tries to remove the paper by grabing the trailing edge of the paper and pulling it back out of the ADF the way it went in. If there is any creases or holes in the paper the paper may catch on a mylar and then drag the trailing edge of the mylar back up the paper path. This is called a flipped mylar.

Now when paper is fed through the ADF the paper will hit the flipped mylar and jam. If your lucky the paper may force the mylar back to where it should be but often a technician will be called to fix the mylar.

I can just use a spring hook or tweezers to gently pull the mylar back into place but care needs to be taken not to do any more damage. Folds and creases can be flattened out but tears and holes will lead to the mylar needing to be replaced.

So if your ADF jams then you should first try to pull the paper out of the ADF in the direction that the paper would normally be fed. If paper needs to be pulled back through the paper path then please keep the mylars in mind and be careful.

Why I started this blog

The obvious reason for why I would start a blog like this is so I can winge and complain about my employer and/or customers. This is only partly true.
There are a lot times when I would like to explain what I have done and why while fixing a photocopier to a customer but they either don't seem to care or are not technically minded enough to understand. This leaves me feeling frustrated that I can't boast about finding a tricky fault or rant about how the engineers who designed these machines should be thrown out a window.
I can't talk to my co-workers about these things that interest me during a common day as they have their own problems and couldn't care less about my insignificant muttering. This is fair really since I don't want to hear about all their jobs either.
And like all married men my wife doesn't really care about what I do all day but just wants me to listen to her tell me about the trouble the kids caused or the latest rummors about the neighbors when I get home.
So I am turning to the internet to vent my thoughts. Maybe someone will read this one day or maybe it will sit on a server somewhere collecting dust. Doesn't matter really.