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Wire Wrapped Connections....?

mustang1102

mustang1102

AK Subscriber
Subscriber
Why did Pioneer (and I assume many other manufacturers) wire wrap all their connections to pins instead of soldering them on....?
If it's necessary to remove any wire wrapped connections when making repairs, is there any reason it is not a good idea just to solder the wire back onto the post when completed..?
 
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ill get lots of flak for this im sure but in my humble opinion it was done for two reasons first it was probably much faster than soldering and time is money,secondly theres a danger of disturbing the pin's solder contact to the board itself when soldering the wire to the pin. certainly a quality assurance issue by itself, it does depend a lot on how this is done and the solders used on the board and pins..lots has been written here by people more knowledgeable than myself that might disagree.but thats the way i see it. i dont see how it can be superior relative to the electronics involved, but again i dont pretend to know everything. from an appearance/extra work point of view i try my level best to leave them intact. there are those that say that a cold weld is produced on the pin corner's on the wrapped connections. i know this is true as ive unpeeled a lot of them on used boards.at the same time ive had even more that unwrapped effortlessly without breaking the wire,apparently all wraps arent done to the same tension.ive worked on some old sets that had the wire wraps soldered as well,particularly on the tuner boards.its impossible to know but on some of these sets i'd swear on a stack of bibles i was the first to be inside the thing but who really knows? if you ever work on a qx949 there are some boards that CANT be accessed without removing wires and or the pins with the wire.as you cant access the pin to desolder it how would you ever re solder it? its been stated here that re wrapping is a no-no as you've lost the sharp edges after the first factory wrap. so i guess the only thing you can do is solder them after a break. and somehow they seem to work just fine. the boards are sensitive to heat and run delamination and they arent all the same from set to set as far as fragility its just the luck of the draw. and board damage trying to remove pins for the sake of a wire wrap seems counter productive to me but thats just my opinion.
 
The wire wraps are noted to be strong, durable and resistant to external processes like humidity, physical shock and heat. In most cases, it is very easy to desolder the pin from the board and continue to work without disturbing the wraps.
 
There are several videos on YouTube showing the old Japanese electronic assembly lines back in the day.
Interesting to see that they all used electric wire wrap guns apparently for speed and ease of assembly.

Bob
 
AT&T Western Electric were the wire wrap kings in the early 1960's into the 90"s They had it perfected on different scales. All the Electronic equiptment was wrapped and so were all the cross connect points. It was fast and solid. So picture yourself inside of a equipment bay where modular boards were swapped whenever needed. On the backsides of these bays were millions of wire wraps. There are many different tools still used today.
if you need to remove a wrap there is a tool that backs up the wrap and it can be lifted right off the pin if there is slack. it can be straightened out and re wrapped when needed. No reason a amp chassis should be different. rarely we would solder over one but could.
 
Champco said:
if you need to remove a wrap there is a tool that backs up the wrap and it can be lifted right off the pin if there is slack. it can be straightened out and re wrapped when needed.
Click to expand...
Try it, you will find the wire is too brittle, too knicked to reliably be used again for re-wrapping, that is why we solder them or leave alone and un-solder the terminals if they need removing.
 
in the 1970s, the emerging mini-computers had a backplane that couple all the horizontal
(or vertical boards) that contained the CPU (not todays cpu on a pluggable set of pins)
and all sorts of boards with various I/O combinations (printer, paper tape reader, ADC,
D2A, etc). the interconnection used wires on the massive array of pins in the backplane.

you could not solder any wire in this dense grid, you could only wirewrap the signals,
the power, grounds, etc.

its use elsewhere predates the high density PCI-e sockets and corresponding traces/lands
of today's motherboards.
 
In the mid 70s I worked on Telecom gear and built many test racks with wire wrap. Usually if I needed to move/remove a wire I replaced the wire because it was nicked and broke too easily to safely reuse. The pin itself was part of a board edge socket mounted in a shelf chassis that would have been difficult to replace. The chance of wrapping a new wire in exactly the same place as the old wire was so small I never considered it a problem, and never had a pin connection failure. These days I would solder a wire that had been unwrapped and re-wrapped, though I try never to unwrap a wire during a repair on vintage audio gear.
 
Don't get me started on this one, people. The "Pioneer Look" is great if you can maintain it but if the wire has to be replaced and you don't have the proper replacement wire and tools to do the job, direct solder wire to board is the way to go (unless you can get the solder to stick to the wire-wrap posts). I have used PCB TB modules, too, as I did in my SPEC 2 restore.
 
Wow, who knew that this simple question would generate such debate. That’s what makes AK great, such a diverse group of people that are so enthusiastic about the preservation and restoration of this equipment. I thank everyone for responding, it has been very enlightening and enjoying reading all your responses. Always willing to learn something new from you guys.
 
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