Checking hard wired fuses

[Mopar Freak]

Hey folks, How do you people check hard wired fuses, like on the power supply of a KM 3035? I was told to check for 24 volts on either side of the fuse. (I did not get a chance to check this yet). Someone checked it the old way for continuity with the power off and it checked bad. Another company said the board was fine. Was the fuse checked wrong? I hate looking stupid! I have never checked a hard wired fuse. Thanks

[blackcat4866]

Canon is well known for hiding inline fuses in a harnass, but not Kyocera. I haven't worked on many of these, but I have not yet run into inline fuses on Kyocera.

Ain't it a treat ripping apart a harnass for a fuse your not even sure exists?

=^..^=

[Mopar Freak]

Black Cat, Let me make sure I am describing this right. These fuses are out in the open on the power supply board. they are not in a bracket where u can pop them out and check for continuity. they are soldiered into the board. Thanks

[bsm2]

check for 120 volts into board
check out should be 5v 24v and gnd lines

I am guessing you have no power?
If you have a fax board on it or finisher or feeder you can unplug them and see if you get power to come back on

see if you can flash machine with a bufflo cf card thats the only one that works on that model ,other cf cards will hose it up and you will have a dead machine

[Mopar Freak]

It has power, one main motor wouldn't fire. The tech that checked it said the 2 fuses on the power supply were bad by checking them for continuity with the power off? Again soldiered to the board?

[bsm2]

any c codes?

[blackcat4866]

If this sounds confusing, it's because it makes no sense to me. I have attached the same diagram, so feel free to become equally confused.

F1 & F2 fuse the hot & neutral legs of the AC input.
but neither of these are marked on the PCB diagram (attached).

F101, 102, 103, & 104 are marked on the diagram but their purpose is not defined.

There is no reason that you cannot meter ohms across these fuses with power off/disconnected, or meter volts with power live using a frame ground.

Since this doesn't seem to be terribly useful, I'll throw in another possibility: A bad main board can cause the power supply to turn itself off, seeming like a bad DC PS.

Hopefully you can use this information, somehow.....

[bsm2]

you can check fuses power off and ohm them out

can power board fail sure, not clear as to what problem is with machine always think simple things before you brake out meter and start tracing circuits and trons.

I have seen good techs bypass the easy stuff and spend hours on something simple

so do we have panel lights? codes?
dead machine? any fans?

email me direct if you wish
bsm2@netzero.nethttp://www.copytechn...s/rolleyes.gif

[Mopar Freak]

It had a C2000 code. Fans would start and one main motor would start, then C2000. Supposedly the pwr supply was fine and just needed a main motor. So these fuses can be checked with or without power? I just figured you could get a false reading because they were soldiered into the board, rather then popped out and checked seperate from the board. Like in the old days!

[blackcat4866]

Personally, I prefer to check those fuses live, metering voltage at both sides of the fuse to frame ground. If the fuse is open or even partly open there will be a voltage difference.

The ohm meter doesn't draw much, and if there is a poor connection it may not show up on the ohmmeter, but will definitely show up at full current draw.

One of my instructors would take a power supply mini-fuse and wrap one end with two wraps of scotch tape to bug a machine. You could take that fuse out and it would always test fine. Put it back and still no voltage? The tape was nearly invisible. I won't ever get tricked by that again.