HP Original Toners
Maintenance Kit
Fuser
Spares
HP RM1-4578 PSU for HP P4014, P4015 & P4515 Printers.
HP Part RM1-4578 is the power supply assembly for the P4014, P4015 and P4515 printers. The newer M601 series use a different part RM1-8393 (220V). Where 110 Volt Power supplies are used (North America and Japan) the parts are RM1-4549 (110V P4014) and RM1-8392 (110V Ent-M601).
Laser Printers use a power supply built for the mains power of the region where they will be used. (In the US they might call it "line power"). The laser printer fuser uses pulses of high power and the machine must be set up for the region where it will work.
It is not always easy to reconfigure laser printers from 220V to 110V and vice versa. We don't know the specifics in this case. The fusers are also different. Manufacturers don't support such a change and it would breach warranty.
The P4014, P4015 and P4515 all use the same power supply board. Unlike some printers this single board provides the low voltages for the processors, the 24 volt supply for the motors, switching of mains power for the fuser and the supplies of several hundred volts (and more) for the electrostatics of the print process - precharge, developer, transfer and fuser rollers.
Note that the power supply board is potentially dangerous in every way. However it is buried deep in the printer and users are protected by the cartridge door switch which cuts everything except the low voltages for the processor if the user gets anywhere near contact.
The board is located in the lower back of the printer body above the cassette tray recess and below the paper-feed belt assembly RM1-4548 and the fuser. The high voltage contacts rise from the front edge to the transfer roller CB506-67903 and up the left cartridge guide.
The power supply ciruit board is quite large and complex because it does several things:
- Mains filter: the public power network carries rather dirty power - spikes from electric motors and flourescent lights as well as lightning. Power is cleaned up to prevent this mush interfering with the computer circuitry in the printer - and to prevent the printer adding it's own contribution to the problems.
- Fuser supply and safety cutouts. The fuser draws mains power at several amps to provide instant heat for sheets of paper passing through. The printer only needs pulses of high current. Incidentally this is why laser printers should never be plugged into a UPS or computer protection extension cable - the printer is an intermittent massive overload and as a result it can "crash" itself.
- Low voltage supplies for the printer's computers. The printer contains two computers:
- One usually called the DC Controller (DCC) deals with all the printers motors and sensors. It can print in a very rudimentary fashion - the stripes produced by the engine test button.
- The formatter is a more powerful computer that deals with print-jobs sent from the computer, interprets the print language and divides the result up into pages. As it happens some of this work is superfluous and could have been done from the computer driver that provides print-preview so sometimes the formatter just receives and prints a bitmap. Nevertheless this all needs negotiating between computer and printer.
- The power supply also provides the high voltages used in the electostatic print process. Laser printers work by electrostatics, using high voltages to charge the drum, attract toner from the developer to the drum, then from the drum onto the page passing across the transfer roller. There are also a couple of voltages used to clean the fuser rollers.
- Finally the power supply board carries fan and thermistor signals from the left side of the printer to the DC controller located in the right side of the printer.
The power supply board is central to the printer's operation and could be implicated in a huge range of faults. Technicians who work on desktop computers will know that the PSUs are one of the main sources of trouble. It would be no surprise if a printer power supply caused trouble. In practice this doesn't happen all that much which is lucky. It is almost impossible to work on the power supply board in-situ because it is buried in the middle of the printer with almost no way to get a meter test probe in.
Diagnosing power supply issues can sometimes be easy; the printer just won't power up. Check the power leads to make sure they can provide power for something else before concluding the printer is dead. An issue with the electrostatic components might be more difficult; they might have to be inferred from behaviour - solid white or black pages tend to imply a voltage down. Check the connection springs before concluding the power supply itself is bad.
Caution is advised when having any dealings with a power supply because it carries voltages and current that can kill. It is conceivable that the board can hurt out of the printer because there are two large reservoir capacitors in the "PRIMARY" section. Reservoir capacitors should be discharged when power is off but may not be; many engineers have experience of this. Nevertheless the board can sometimes be fixed. Most of the components are "discrete" and can be bought. Look at a suspect board for signs of leaky capacitors, burned resistors. There are two fuses - one for the low voltage supply and another for the fuser and they can blow because of a surge without implying any other damage. Replacement costs pence. However you may not be so lucky, some of the components are not easily obtainable and untestable
As suggested already, everything in the printer depends on the PSU. Erratic problems that seem electronic in nature - print jobs stopping at random, memory, EIO and other communication issues might prove to be power supply related.
Do make sure the printer is plugged directly into a wall socket and not a UPS, mains filter or even a shared extension cable. The power pulses drawn by the fuser can drag down the voltage sufficiently that the printer crashes itself. This would look like a power supply fault.
To see RM1-4578 in context in the engineering diagrams click here.
HP Information
A wildcard query to HP Partsurfer elicited the following in July 2013:
HWP-RM1-4578-000CN Power Supply Assy 220-240V
RM1-4578-000CN AC Power supply assembly (electrical components) - For 220 VAC 240 VAC
RM1-4578-050CN ELECTRICAL COMP ASSY (220V)
RM1-4578-190CN ELECTRICAL COMPONENTS ASSY.A A
Enquiry on RM1-4578-190CN just gives:
RM1-4578-190CN ELECTRICAL COMPONENTS ASSY.
Since this part has a 110V sibling we checked that as well. Wildcard gave
HWP-RM1-4549-000CN Power Supply Assy 110-127V HWP-RM1-4549-030CN Power Supply Assy 110-127V RM1-4549-000CN AC Power supply assembly (electrical components) - For 110 VAC 127 VAC RM1-4549-030CN AC Power supply assembly - For 110 VAC 127 VAC RM1-4549-190CN ELECTRICAL COMPONENTS ASSY.A A
and HWP-RM1-4549-000CN Power Supply Assy 110-127V
RM1-4549-000CN AC Power supply assembly (electrical components) - For 110 VAC 127 VAC
and then:
RM1-4549-190CN ELECTRICAL COMPONENTS ASSY
The RM1-4578 / RM1-4549 is compatible with all ten printers in the series; the HP LaserJet P4014, P4014N, P4014DN, P4015N, P4015DN, P4015X, P4515N, P4515TN, P4515X and P4515XM.
The RM1-4578 might also be known by the successive variant numbers RM1-4578-000CN, RM1-4578-050CN and RM1-4578-190CN. The RM1-4549 has a similar progression.
The GTIN (EAN/UPC) for RM1-4578-190CN is 5711045564543 according to Icecat
Notice that HP don't necessarily call it a power supply; sometimes its the less specific electrical components assembly
.
Web Research
A Google Query on 26th July 2013 using the product code RM1-4578 suggested About 12,300 results
.
The number one listing in Google was an Amazon entry by Zar Systems at £508.00 saying "Usually dispatched within 2 to 3 weeks." perhaps they make them by hand in gold? They were also offering a refurbished one for £145.00. Chiltern were at £346.39 and theconsumablesdepot at £235, LambdaTek at £284.90 ukcomputers at £373.57 and hp-web at £359.52 but no stock. However stjohnsuk on eBay had a bid starting at £0.99 but with £29.99 postage.
We found no information using a search on the product code that did more than confirm the existence of the part by reiterating the HP partsurfer description or distributor lists. We looked at 20 pages and found nothing but list-driven web-vendors.
A search on laserjet P4014 power supply
gave About 936,000 results
; it too was dominated by vendors selling second-hand boards at high prices. Many of them seem to be including the paper-feed assembly because they don't know it isn't part of the power supply.
This search gave slightly better information
- Light Print on fixyourownprinter.com fix is to put conductive grease on the HV contacts.
- arbikas.com offering a PDF of the service manual - which is certainly one of the best sources of information.
Supply Situation
The P4014 printer series is no longer manufactured and the RM1-4578 power supply is not compatible with anything else. The M601 RM1-8393 supply makes the same voltages but the pinouts are different. This is the case with most printers - they all use 3.3V and 24V but there is no way to swap the circuit boards. The printers were made uniquely by HP (or should we say for HP) so they seem likely to be the only source of new, original RM1-4578 boards
We note a couple of Chinese manufacturers claiming to be original manufacturers of new parts but the worldwide demand for this part will be trivial so it stretches credibility that anyone would make them. We think what is offered are clean pulls or what the industry prefers to call "refurbished" parts.
Refurbishing doesn't mean anything much with electronic circuitry. Other than checking that it works and is physically clean there isn't a great deal that can be done. The bulk of the circuitry on these is an ordinary pulse-mode supply so they can be repaired but that would be regarded with reduced confidence.
HP and their distributors do supply original parts but we found no UK vendor offering them for less than £235 and since that is lower than the cost from distributors we think they have failed to update prices. We think original RM1-4578 PSUS will not be offered for less than £300. Anything else is a "refurb". The price of refurbs is arbitrary but we can find them for £41;.
The part is listed by a couple of UK distributors and one holds stock of 2 new boards. A distributor that stripped half a dozen decomissioned printers has four boards in stock, so only a couple have sold. Demand for the part appears to be low.
In the P4014 series the RM1-4578 is deep inside the machine and quite difficult to get at. If a power supply board fails it could damage other electronics and it won't be easy to change without stripping a significant part of the machine. The balance of probabilities is that people will risk refurb boards, but will scrap the machine rather than buy a new one. From HP and their distributors point of view the PSU board is a complicated spare to have carried so the price of new stock may be justified.
We can provide these parts when required. The price is about £300 for new and about £50 for "refurb" which largely reflects the logistic costs of obtaining one.
These are guidelines, our prices change with distribution lists - see the catalog. Stock numbers indicate there is not much call for the part. It is offered as a convenience rather than because it will solve many problems.
Copyright G & J Huskinson & MindMachine Associates Ltd 2013, 2015, 2016. Some pictures derived from HP User and Service guides. These technical pages do not constitute an offer for sale; just our knowledge at the time of writing. See the catalog. Sales pages on this Web site use cookies to store user information. We also use Google Analytics to track site usage patterns.