MPC2800/3300 display dead mc tries to start (SC202) - SOLVED!

[Gift]

@Polarbear:

Thanks for sharing this information - now I can't wait for the next BICU to blow up

Is there any SMD resistor type to recommend - I found several types (wattage ratings/dimensions) with zero ohm - not shure what to pick

[Polarbear]

@Polarbear:

Thanks for sharing this information - now I can't wait for the next BICU to blow up

Is there any SMD resistor type to recommend - I found several types (wattage ratings/dimensions) with zero ohm - not shure what to pick

@Gift

I just looked for a device with similar "ballpark" values as the ones surrounding the faulty one. Even at this stage, that repair is still working!
Seems like these resistors are used as fuses, to protect the input side of the circuit.

If memory serves, the replacement came off a bicu board of something like a mp2352 or thereabouts, as they share similar components and seem to have been designed in the same era (components wise).

[Gift]

thx for the update,

had a chance to get into this, too - I simply replaced the polygonmotor first and after the OP didn't came up I knew I had a faulty BICU. I simply placed "some amount" of solder over the faulty resistor to bridge that thing and voila - all fine. I'm aware that this means there is no fuse-like protection of the affected part of the circuit but with a new polygon motor I'm willing to take that risk (unlikely it will blew again considering the expected, remaining lifetimes of the machines in the field).

[Polarbear]

thx for the update,

had a chance to get into this, too - I simply replaced the polygonmotor first and after the OP didn't came up I knew I had a faulty BICU. I simply placed "some amount" of solder over the faulty resistor to bridge that thing and voila - all fine. I'm aware that this means there is no fuse-like protection of the affected part of the circuit but with a new polygon motor I'm willing to take that risk (unlikely it will blew again considering the expected, remaining lifetimes of the machines in the field).

Gift, did you order the modified polygon with the new part number? Then you should not see this problem return. Ricoh maintains that the mod solved the issue.

[Richariri]

We found a tiny resistor (close to the lower right power connector [they all have a "o" printed on them in white] was burnt so that the "o" was not visible. Replaced the resistor and started the machine, and all is well.

you sir are my hero, I have been waiting for someone to identify the resistor and confirm that replacing it works.

I had to replace the entire polygon mirror and BICU in one go and would love to salvage the BICU.

Thank You

[Gift]

Gift, did you order the modified polygon with the new part number? Then you should not see this problem return. Ricoh maintains that the mod solved the issue.

Yeah I saw the bulletin and have a modified motor in stock since we still have some first/second-gen MPCs in the field.

[iluxa]

Excellent! Has worked, many thanks!

[iluxa]

@ Polarbear
Excellent! Has worked with MP C4000, many thanks!

[fshead]

Sorry for the low res cellphone photo. Look for the black resistors between the large white power connector and the row of capacitors. They are black surface mount devices with a white "0" printed on them.

I am not sure about the value, but if you measure all of them with a DMM, you will find that the one (which is normally discoloured as well) will have a vastly different value than all the others around it.

That one you will have to desolder and replace with another good one. It is normally a good idea to change the polygon motor assembly as well as this causes the fault - and Ricoh has brought out a modified motor that is redesigned to prevent this failure in future.

Hope this helps.

I JUST did this repair on a unit that went bad 2 years ago.
didnt use a new poly but cked the solder joints on it b4 insttalling it."Resistor SMD code" from a bad mpc3501 bicu brd.
there are 20 spares on them but a pain to desolder cause they fly away wth any force and one can not see where..

[Oze]

Bugger doing component level fixes on an MPC2800..!!!
The machine is now on the "not supported" list from Ricoh and getting parts is going to be difficult shortly so I CAN understand the need for soldering and the like but I'd have sold them a new machine.
And damn this is an old post