working wtih those little wrapped lead connections?

[sydsfloyd67]

Are there any tips to disconnecting and reconecting the little wrapped lead connection one finds in these vintage recievers? Should I try to "unwrap", or just pull them off and push back on? (Why did they do this rather than solder, and was it done by hand or machine?) Thanks, -sf

 

[crooner]

It's better to unwrap it and then do a couple of turns and solder the connection.

The reason it was done was economies of scale. Given the large production numbers the Japanese (specially Pioneer) were turning out, it was a natural choice.

The wirewrapping was done by an operator using a specialized machine which saved time during production.

It was also claimed that wirewrap would make a more reliable unit since the possibility of a cold solder joint was eliminated. This is debatable though.

Pioneer ended up soldering many critical wirewraps during production, as I have seen in many of their 1970s offerings.

Wirewrap was first used in consumer electronics by H.H. Scott. It was touted as "aerospace" or "space age" technology.

My guess is that this technology found its way into Japanese electronics after H.H. Scott folded in the early 1970s.

 

[SansuiSamRI]

Wirewrapping been used in electronic equipment for many years, not specially audio products. Its commonly used for prototyping, but can be used for production units. It can be done with a specialized tool that looks like a drill. The tool has two holes in the end - one for the pin and one for the wire. The gun turns the wire around the pin. They also make a very inexpensive hand tool for doing wirewrap. Like Crooner said, a couple turns and solder should be fine, but the hand tool is available.

Here's a cheap one http://www.elexp.com/pro_3wte.htm

 

[markthefixer]

Wirewrapping depended on those very square sharp corners for the connections. The theory was that the sharp edges would cut into the wire and make a Gas-tight connection(i.e - corrosion resistant, what we use deoxit to eliminate). with 4 connections per wrap and 10 turns they had 40 chances to get it right... was primarily for solid 30 gauge wire on .100 center ic pins.

The sharp corners nick the wire and when unwrapped it tends to break, so get at least 1 turn of GOOD UN-NICKED wire around the post before soldering it to the pin- to avoid a very frustrating breakage.......
(some insulation stripping is in order, approximently 1/4 inch or so.

Try working with pins on .156 inch centers across a 2 foot by 3 foot area
with 30 gauge wire all the SAME color..... (PDP-8i computer backplane)
That was fun when the wires broke....
:cry:

 

[jayceem]

I have been satisfied by merely using deoxit on all wire wraps, not soldering. If you feel you must solder then no need to go to extreme trouble of unwinding on all those posts either. Just apply enough heat at the top of the post for the solder to seal the first wrap, that's all the need rather than having too much heat and the unfortunate consequences. :yes:
But remember solder has it's own sound too. :yuck:

 

[kcollins4]

Haven't heard any solder lately.