HP RM1-5051 fuser motor for HP P4014 and M601 Series Printers.

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HP Part RM1-5051 is the part number given in the service manuals for the fuser drive motor used in the HP P4014 / P4015 series and M601 series printers.

The same fuser motor is used in the P4014, P4015, P4515, M4555 MFP and Enterprise 600 M601, M602 and M603 printers. - Or at least it is largely the same but not always labelled with the same number.

A separate fuser motor was a bit of a departure in design for the P4014 series.   Earlier printers generally drove the fuser from the same main motor that provided paper pickup and drum drive.

RM1-5051 is a DC "outrunner" brushless motor. The external rotor holds permanent magnets giving it mass and high torque at a fairly low speed. The motor includes a circuit board sticking out unusually far which carries the motor driver chip.

There are a few variants of the motor. HP often use Nidec as a supplier of motors. Some motors we have seen have been labelled Nidec, but one not. One version didn't carry a definite manufacturer sticker (possibly Nidec, could be Minebea Electronics Motor (Zhuhai) Co.,Ltd who make such things?). Dismantling a P4015X yielded a Nidec motor labelled RM1-5064, and an M602 gave a motor labelled RM1-8287; neither code gives a response from HP Partsurfer so they look like HP/Canon codes but probably reflect internal manufacturing and implementation differences. They do look slightly different but have the same 10 pin connector.

The driver may be an SLA5212 - we thought we had evidence of this in the past. A bit more research might also suggest a Rohm BD6761FS "Three-phase Brushless Motor Pre-driver for Paper Feed". It is interesting that the printer industry is big enough to have its own motor drive chips.

RM1-5051

Laser printers colour the page using toner powder, fine ground plastic. In the P4014 and it's successors the toner is polyester because this gives a low melting point. The fuser has a heater that softens the toner and a pressure roller that forces it into the paper. The fuser motor needs some power because of the load imposed by the pressure roller forcing up against the heater.

One reason to have a separate fuser motor is that it can be reversible. It wouldn't make sense to reverse a fuser, of course. When the P4014 fuser is reversed it disengages the pressure roller in two senses. The pressure roller doesn't turn, instead it runs a cam-shaft that releases the pressure between the heater and roller, this makes it easier to remove paper after a jam. A single main motor could not do this because the drum and paper feed rollers cannot be reversed. The older LJ 4200 fuser design has a little green thumbwheel to assist paper removal and the P4014 fuser doesn't need that.In principle the separate motor may also help improve drum-life since the drum motor can stop as soon as paper has departed, whilst the fuser carries on. This allows the the drum to stop about a turn sooner than if it were directly connected to the fuser.   The drum might also do cleaning actions whilst the fuser is idle.

LJ-M601_right_side_stripped

Perhaps luckily, faults with the fuser motor do not seem common.

The motor is not the worst part of the printer to get access to, that is probably the power supply. It is necessary to remove the top and right side of the printer, the DC controller and the formatter connector and the underlying plastic cable guide. Since the DC controller interconnects the rest of the printer you have a forest of wires to put back in the right place.

Fuser Motor Faults

The fuser motor and the fuser CB506-67902 itself are connected via RC2-2432 the fuser drive side plate which is a short drive-chain of cogs decreasing the speed and increasing the torque to drive the fuser pressure roller. The drive side plate has an additional role keeping some pressure between the body of the printer and the fuser roller drive gear. This job was done by the swing-plate-assembly in the older LJ 4200 printers and was one of it's few notorious faults. Web research suggests there may still be a minor issue; perhaps it is an inevitable feature of having an easily removable fuser. In some recent printer designs HP build the fuser motor onto the fuser itself.

Fuser motor faults are supposed to give 59.2 errors according the service manual. Some sources suggest there is a 59.02 error for fuser motor start failure and and 59.03 for rotation failure. (note the contradiction of the numbers with those in the service manual).

If there is a 59.2 error there is an obvious question whether the motor is stalled because of the fuser or because of a fault within itself. Take the fuser out and check that it turns in line with expectations, or with what other fusers do. The fuser will have a very varied reluctance to turn depending on whether it is turned one way or another so that the pressure roller cams engage or disengage. The printers diagnostic mode will help demonstrate that the motor can turn the fuser.

Outright failure in a brushless DC motor is rare, the driver chip will tend to cut out before it overdrives and damages the coils. The chip and it's surrounding resistor network tend to show damage visually in the form of staining due to overheating.

To see RM1-5051 in context in the engineering diagrams click here.

LJ-P4014_M601 fuser motors

Although the service manuals give the fuser motor part number as RM1-5051 the motors dont physically have that number on them.

The motor with a white label says: Nidec 48M060B111 RM1-5064 01 DC24V 1.56A and on the circuit board NIDEC 14004498. It has a fibreglass board.

The motor with a yellow label says:Nidec 48M060F031 RM1-8278 01 and on the circuit board Nidec 14007591. Its a paxolin board.

Internally both boards have a controller and three driver chips but they are between the circuit board and the metal of the motor mounting - and it looks as though getting at them would damage the motor.

As you might expect, those numbers found no direct hits on search - the parts were made specifically for HP. Shortening those numbers for search gets eBayers flogging off surplus at a variety of prices.

The LJ-M604 fuser motor gets a new part number "RM1-8928-000CN" however the picture in the service manual is the same. We don't yet know if the motor is just a variant of the those examined or something new.

HP Information

A wildcard query in August 2013 to HP Partsurfer yielded the following ...

HWP-RM1-5051-000CN Fixing/Fusing motor assy
HWP-RM1-5051-020CN FIXING MOTOR ASSY
RM1-5051-000CN Fuser motor (M299) assembly - Drives the pressure roller and feed roller when rotated counterclockwise it releases the fusing pressure for easier jam removal
RM1-5051-020CN Fuser motor (M299) assembly - Drives the pressure roller and fuser delivery roller - Pressurizes or releases the pressure roller

The fuser motor seems to have been through one or more design variations - not many for a part with the potential to make trouble.

RM1-5051-020CN Fuser motor (M299) assembly - Drives the pressure roller and fuser delivery roller - Pressurizes or releases the pressure roller

... and lists The LaserJet M4555 and Enterprise 600 M601, M602 and M603 as uses. This seems to be one of PartSurfers omissions - the service manual and inneumerable websites agree this motor is used in the HP LJ P4014, P4015 and P4515.

Icecat says the EAN/UPC is RM1-5051-020CN = 5711045059889 and says the category is Power Adapters & Inverters (wrong). There had been 38 product views suggesting a low level of interest in the part.

The motor is labelled something like DNN08M02W21B. and has a black "M" stylised as a magnet on a yellow background as a logo. At the moment we haven't firmly determined the manufacturer for that one. Web-research had already determined the other parts

  • RM1-5064-000CN but there is no record of that in HP Partsurfer and Recoll found nothing
  • RM1-8287-000CN again no record of that in HP Partsurfer and Recoll found nothing.

Since Recoll found nothing in the service manuals and Google finds little but people selling refurbs these codes don't seem to mean much.


Web Research

A Google query for RM1-5051 gave About 18,000 results (0.23 seconds)

RM1-5051

eBay (tradepriceprinters) refurb £13.95, amazon.co.uk (Zar) £84.00 + £12.00 delivery, printerworks.com, new $59.99, refurb $44.50, partshere.com new $73.31, refurb $47.65, ilgs.co.uk refurb £15.33, alibaba.com (GuangZhou Kedi) no price, laserxperts.com refurb $14.50, sparepartswarehouse.com $71.66, sparepartswarehouse.com again, impactcomputers.com $62.37, pricegrabber.com (UpgradeBay.com) $328.32, printersupplies.com refurb $62.00, alibaba.com (powershow) no price, eBay (strepx) $23.50, ebay.com (oemconnect) claims new $59.99, feedroller.com refurb $56.53, zhhpparts.en.made-in-china.com no price incorrect details, hpstock.com £0.00 inc Vat, laserpros.com login reqd, amazon.com (Toner and Printer Parts) $56.53 + $5.95 shipping, alibaba.com (Guangzhou Kedi) no price, newfuser.com new $75.63, everprint.com ¥1816.00 CNY, memory4less.com $86.15, aliexpress.com (ALEX Excellent Parts Store) US $24.00 US $10.53 shipping, lbrty.com no price, icecat.us no price, partsurfer.hp.com - just the P4104N CB507A list, enxmag.com note on the motor faults, cdw.com no information or price.

Prices noted are for a new item without tax, however some suppliers don't seem to distinguish refurbs. The list is as encountered. We haven't bothered with currency conversion - half of our readers are outside the UK and are more interested in dollar prices.

All but one of the sites visited gave no obvious information or help beyond what is in HP Partsurfer or the distributors P&A lists. The exception was enxmag.com which gave a little bit of information contributed by laserxperts.com. lbrty.com generally have more information than they make evident on their site in this case.

A bit more web-research on RM1-8287 showed a Nidec motor in a similar form factor to the RM1-5051. The number seems to be printed on some fuser motors stripped from M600 series printers.

Other Research

We use Recoll to search our internal collection of information and it found RM1-5051 but not RM1-8287 or RM1-5064. Neither were those parts found in distributor lists.

These are rather nice little motors and they ought to have uses outside the printers. In order to test them on a workbench or use them out of context a bit of information is needed. Motors with the "14004498" part number have a legend printed on them describing the pin function.

1GNDGround
2GNDGround
3GNDGround
4REVReverse
5ACCAccelerate
6DECDecelerate
7FGthought to be Frequency Generated
8VMMVoltage Motor (24V)
9VMM24V
10VMM24V

Supply Situation

Search results suggest a little interest in the RM1-5051 fuser motor.

The part was listed by three UK distributors in August 2013 but they don't hold new stock. One distributor had 3 refurbed units in stock (from stripping 6 printers). We think demand for the part will be quite low and may often be met from refurbished parts.

"Refurbished" means "pulled from a previously working machine". It is possible to test these motors from the Diagnostics menu or by supplying 24 Volts and the appropriate logic propositions to the motors on a workbench - the HP circuit diagrams give a hint on how this might be done.

We can provide these parts new or refurbed when required.   There is no great advantage in "new" as nothing specific is likely to wear out, in fact "refurb" may have the advantage as it could be considered to have been given a long-term test.   Pricing for a new is about £45. For refurb price is £16 and at the time of research availability is next day but that could change rapidly with time and availability.

These are guidelines, our prices change with distribution lists - see the catalog. Stock numbers indicate there is not much call for the part.