1526 printer - repair(able) or not?

From: Ville Laustela <ville.laustela_at_gmail.com>
Date: Sat, 5 Apr 2014 22:29:17 +0300
Message-Id: <C2F84607-D99D-4A65-B651-B751E237099E@gmail.com>

Some years ago I was given a Commodore 1526 matrix printer (like this: http://bilgisayarlarim.com/Commodore/1526/), in a rather sorry state. It's also a 115V version, meaning that I need a step-down converter to use it in here 230V land. I also presume that the ribbon is by far dried and due to replacement.

Powering the unit (with the step-down converter) results in absolutely no signs of life (other than the faint hum from the mains transformer).

Today I had a closer look and found out that:

- fuse is good, and the output from the transformer is good (as per the service manual here: https://archive.org/stream/1526MPS-8024023ServiceManual314003-031985Apr/1526_MPS-802_4023_Service_Manual_314003-03_1985_Apr#page/n9/mode/2up)
- all chips are present and re-seated
- 5V supply is present on all big IC's
- 26V supply seems also to be working
- all IC's get warm (quite warm, but none clearly hotter than others)
- there is no life on the LED (on the paper advance button on the front panel) except that when I disconnect mains, there is a faint flicker
- pressing the paper advance while powering up (to print self-test) gives no reaction at all
- as a test I replaced the 7805 regulator and the electrolytic caps around it, but it made no difference

Also I am wondering that there is a brown cable coming out from the primary side of the mains transformer. It's not connected (the end of the wire is taped and it's hanging loose) to anywhere. Could it be a connection for wiring the transformer for 230V operation? That would ease testing of this a great deal.

There is also a possibility that the unit has been powered from a 230V mains by some previous owner, and nobody knows what damage it might have caused. Even all the big IC's might have been killed by that! If they would be fine, those 6532As and 6522 could be valuable in other repairs.

I have put some pictures of the board here:

Any ideas? I basically would like to have *some* Commodore printer working, preferably an old one. This would do, but it's not giving any sign of life at the moment and even it would get fixed I would still need to worry about getting a new ribbon (and finding wherever I put that one box where I had perforated printer paper...). Also it's a bit yellowed and there is a crack on the top-cover so it's by no means in good condition.


Ville Laustela

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Received on 2014-04-05 20:00:02

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