Greetings,

I am trying to figure out how to reset or bypass the Magicolor 7300 print unit (imager) chip. I have determined that the top four pins are for the toner fuse & the bottom 4 pins are for what I am interested in the print unit counter. I can only disable one bottom (middle) pin before the printer tells me there is a print unit error.

I guess they use an EEPROM because it has memory (it keeps track of the print count), and even though the CMYK chips are identical the chips are not interchangeable - they must have a CMYK bit.

I have a very detailed picture online - hopefully some can tell me what I have:

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I am trying to figure this out too but using the control panel instead. I have been starting up the printer using different key commands.

I'm not sure if this works properly on my machine, but if you start up holding the left arrow and menu/select button until it says warming up, you are presented with erase eeprom yes/no. If you select yes on mine it just seems to erase page count for colour and blackwhite. Does this reset all items on yours? I don't know anyone else who has a similar machine to test it on.

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The EEPROMs are designed to stop end users cheating the system. They do keep records on how many prints each of the units have done but they also have information like what area the toners are for. For example the toners we get are for Asia Pacific printers and will only work in AP printers. This stops people from importing "cheaper" toner from other countries like the US and using them in their printer.

These chips are designed not to be cheated. You might remember and even read within this forum about people buying new fuses to replace in their consumables to extra prints from them. The manufacturers have caught onto the idea and realise if end users do this they won't buy as many new consumables so they have stopped this buy using the EEPROMs.

The page count erase that you have found by the button combos is used to reset the page count on the printer. This is used in the factory. Obviously the factory prints to the printer as QA and so run a page count up on the printer. What they do is then reset this count before it is sold as a new machine. This feature has been removed on any new product.

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From what I can gather the fuse blows when you install a new toner cartidge. The eprom starts counting the units on the actual print unit. Now if the print unit is nearing the end of life then it waits for the toner cartridge to empty before it will say that you need to replace it. I have managed to extend this by refilling the toner so it doesn't empty. I have tried Magicolor 5450 refill toner with limited success (the waste box gets full very quickly) and it leaves big blobs in solid areas. There are two ways of looking at this. One is the eproms in the print units and the other is the main eprom on the controller board. The eproms on the print unit look like they just count cycles. The one on the controller board must be checking this against a 'end of life' value to determine whether it has done its job. If you could change the 'end of life' value that may help. Also it would be good if another refill toner worked.

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At long last I found PERFECT generic toner for the 7300!!

The generic toner for the 7450 works perfectly - and as a bonus - one bottle is almost 1.5 fills...

I have bought it from http://tonerwiz.com

BTW: If you remove the fuse you never have to replace it, and the toner percentage still works!

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Have you tried the 7450 toner? The Magicolor 7450 is the same print engine as the 7300.

Before generic toner for the 7450, I had the same problem as you with it leaking/wasting excessive generic toner and eventually ruined the imagers.

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I had the same problem before I started using the 7450 toner. You have to remove the print transfer belt (actually pretty easy - just be careful, take your time and follow the service manual).

Since it was leaking/wasting excessive toner, more toner was being dumped out than could be cleaned (transferred to the waste toner box). So I am willing to bet you have a pile of toner under your transfer belt (I did).

Let me guess the quality is the worst when it first starts up, and if you print a bit the quality gets better?

Clean your belt, and stop using toner that is not made for the 7450 or you are going to ruin your imaging units...

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To reset take the toner cartridge out...turn printer off...place tape over the metal contacts at the end of the cartidge...replace and restart printer. If your cartridge has totally expired you will need to purchase a new cartridge insert it and restart....Then remove it and insert the old cartridge with the tape on the contacts and restart. This has worked for me

You will find that expired cartridges still have a lot of toner still in them. I could get my cartridges to last a WHOLE lot longer if I could find someone that sold the toner for the 7300...any ideas?

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if you see above - I posted about a year ago, that all you have to do is remove the fuse from the toner cartridge, and works even after it has expired.

It just is kind of annoying for people to post without reading the thread, and then offer poorer advice.

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I reset the print unit chip, shorted the connectors on the chip with a small piece of wire, switched on the printer and did not get it to do full initialisation then removed the wire & voila'

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Sorry mate, can not remember as I did it two years ago.The top far corner of the print unit has two connectors only, going by memory. Short them with a thin strand of earphone wire.Switch on the printer and let it go throught part of the initialising cycle. Switch off and remove the wire. Keep Count of the amount of seconds you let the machine initialise . So if you do not succeed at the first attempt, you keep on adding

seconds to the initialising process untill your Print unit come up with 100% usage again. It worked for me the fist time, and i hope you do it too. Good luck

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7450 toner works PERFECTLY for me. What was the problem you had with it?

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That’s encouraging to know. I have 11 of these units in a high production environment. Plus I have 5 more new in box which I can use for toner testing and parts. The main problem with the aftermarket 7450 toner I tried is “toner dumping” where clumps and specks of toner fall on to the page as it travels under drum. Also uneven density and halo effects around text and graphics. I adjusted the transfer current thinking it would help and had no results. Do you mind telling me where you purchased your toner? I’d sure appreciate it. Maybe they have a better “mix”. Thank you!

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After a lot of printing, I have found that I have the same problem (esp. on the first few sheets to print). This indicates that the print transfer unit has to be removed, and likely a pile of toner has accumulated under the belt has to be cleaned. It is actually pretty easy, if you look on the internet you can find a printer service manual which has detailed instructions how to remove the print transfer belt.

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Has anybody succeded in replicating the print unit resetting method described by PaulG ? I am not sure I want to short out contacts without knowing it really works.

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This works! Taping over the ends of the metal contact points on a refilled toner cartridge will override the 'Toner Empty' warning and print as normal. However, I guess I'll need to watch the print quality since with the contacts covered, the printer will always think the cartridge is full! I've just purchased a refill on ebay: buten22 is the seller. Hope this helps.