Printer help?

From: Dwight K. Elvey <>
Date: Thu Sep 9 15:16:17 2004

>From: "der Mouse" <>
>> I think most of the error messages are listed but sometime it just
>> says something like "replace the xxx board under the main board". If
>> you know what I mean.
>Yeah - but even if it does, it would be reassuring to know that the
>selftest agreed with me about what's at fault here. Or it could say
>something like "such-and-such sensor switch is stuck open", in which
>case I know I probably need to replace a cover or plug something in or
>some such. (There are two sockets with no cables to plug into them as
>far as I can tell; I don't _think_ I have any cable ends hiding,

 Might be for the duplex or some other option.
>> Look at the board carfully. It sounds like you had a small
>> electrical fire. Remove any charred PC board and look to see if
>> traces are burnt through.
>It's not clear whether there is any charred PC board. There certainly
>is _missing_ PC board, but it's not clear whether the black substance
>is charred board or just gunk from the capacitor that I haven't
>scrubbed away yet.
>There is at least one via that is damaged; I can see the little copper
>cylinder sticking up every so slightly from the damaged board around
>it. It's connected to a power wire on the foil side, though, so it's
>not clear whether it's essential or whether perhaps the capacitor
>lead's hole substitutes acceptably.
>It's not that easy to look very closely at the damaged area; it's
>surrounded on three sides by components tall enough to get in the way
>of things like cleaning efforts. I may remove the cap I added and see
>if that lets me scrub it any cleaner.
>> Missing solder mask is not an issue but missing copper is.
>Obviously - though if there's any copper missing on the top layer, it
>appears to be part of a high-area fill, probably ground, and thus
>relatively inessential.
>> I'll look for my manual to see what it says( not here so will report
>> back tomorrow ).
>That would be appreciated. No hurry, though; I'm about to take off
>tomorrow and won't be near the printer for a week or two if I can't get
>it fixed pretty early tomorrow morning.
>> This sounds like a PS board.
>It's not. The caps are right next to the only heavy wires that connect
>to it; I'm sure they're incomng power (the board they connect to _does_
>look like a power supply board) and the caps are just for local
>Also, with the replaced cap, as I said, there are no more pyrotechnics
>and the main power supply does not go into its overload failure mode,
>so there doesn't seem to be anything still shoretd out. The flashes of
>light, though, indicate _something_ was shorting; the one after I
>replaced the cap leads me to fear that there was a short and some
>conductor acted as a fuse. I may get out a voltmeter to see if the
>various chips are getting power (some of them are stock 7400-series
>logic, so finding ground and +5, at least, will be easy).

 Sounds like a good plan of attack. I'm relatively sure that
you have had some electrical fire. The black stuff may be tar.
If so, things like lighter fluid or kerosene should dissolve it.
Received on Thu Sep 09 2004 - 15:16:17 BST

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