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Newbie question...

EasyPeasey

Oct 26, 2019
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Oct 26, 2019
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Hi, I'm new(ish) to the world of electronics and have undertaken to restore a non working vintage integrated amplifier, specifically an Alpha FA-400... the power amplifier board is a separate unit and is connected to the pre-amp inputs, outputs and power supply by wires wrapped and then soldered to rectangular profile metal pins that go through the board specially for this purpose. Does anyone know what they are called and if they are still available? It was just about impossible to remove the tangle of multiple wires twisted round some of them and it might be easier to get replacements (long shot but..) than clean them up...
 

davenn

Moderator
Sep 5, 2009
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Have I posted this question in the right place? o_O


Welcome :)

yup OK here
Ummm, I would have called them wire-wrap header pins or similar ... not sure if they have a more correct name
 

duke37

Jan 9, 2011
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Wire wrapping is not normally soldered, they are used in vibrating situations. The wires can be added and disconnected with the appropriate tools (expensive) so can be used as a permanent bread board.
If your wires have been soldered then you have problems to disconnect them. Replace with a loose soldered helix.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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Unfortunately, I have to agree that you have encountered wires soldered to wire-wrap pins. Back in the day, we would sometimes do this to ensure a permanent connection. Wire-wrap connections are intended to be made ONLY with solid wire. The sharp corners of the wire-wrap pins penetrate the surface of the solid wires during the wrapping procedure, thereby creating a gas-tight metal-to-metal connection between the wire and the pin. If your wiring uses stranded copper wire then it MUST be soldered to the pins because it is impossible to make a gas-tight metal-to-metal connection between the pin and the stranded wire.

Your best bet going forward would be to carefully note the color code (if any) of all the wire connections and then carefully map where each wire terminates on each pin. After doing that, you may want to cut the wires close to the pins and replace them with new wires. Or maybe cut them not so close so you can unwrap them more easily from the pins. Either way, forget about re-using the existing wires. Just replace all of them. Make sure you clean up and re-tin the pins before installing replacement wires. Try not to overheat and char the printed circuit board while laboring over the pins.
 

Ylli

Jun 19, 2018
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Jun 19, 2018
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Wire wrapping without solder using stranded wire is quite common. The wire is tinned first so that the wrapping can create that gas-tight connection.

When I have to unwrap one of these I usually re-wrap as neatly as possible - often shortening the stripped length of the wire, and then adding solder on the connection. Without the proper tools, it is not possible to re-wrap and produce a reliable connection.
 
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