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Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 13th Jan 2019, 2:39 am   #1
Argus25
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Default Through Hole PCB repairs with miniature eyelets:

Through hole pcb's are nearly obsolete now with surface mount being king. I only realized this recently, that they are now truly "vintage".

Recently I acquired a North Star S-100 disk controller board, and got that sinking feeling when I discovered that somebody had been attempting repairs in the past, and I discovered track & pad damage. I think we have all been there and had that sinking feeling, at least those who like to do their own board level repairs.

In any case I had also noticed a very impressive pcb repair done at the factory I think, on my SOL-20 computer motherboard where they had a used a miniature brass eyelet to do it. So I had a go at this technique myself to repair the North Star card.

The technique would also be very helpful on damaged phenolic pcb's in vintage transistor radios. It was pretty easy to make the simple tools to do it.

The result is here:

http://worldphaco.com/uploads/PCB-EYELET_REPAIRS.pdf
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Old 13th Jan 2019, 6:58 pm   #2
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Default Re: Through Hole PCB repairs with miniature eyelets:

Thanks - some very interesting ideas!
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Old 13th Jan 2019, 8:02 pm   #3
vidjoman
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Default Re: Through Hole PCB repairs with miniature eyelets:

Philips used a brass eyelet in their early CD players to link the earth plane through the PCBs. Not reliable as the expansion of the brass caused bad joints and many strange faults. We used to drill through them and fit a wire link soldered near the eyelet to cure the problem.
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Old 13th Jan 2019, 8:58 pm   #4
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Default Re: Through Hole PCB repairs with miniature eyelets:

Yes, the brass has to be completely soldered over & through.
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Old 13th Jan 2019, 9:25 pm   #5
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Default Re: Through Hole PCB repairs with miniature eyelets:

"the technique would also be very helpful on damaged phenolic pcb's in vintage transistor radios."

This was the bit that caught my attention - how to provide new component mounting points for components on those old single-sided "track-peels-away-from-board" PCBs when we have to remove parts for testing/repairing.
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Old 14th Jan 2019, 11:18 pm   #6
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Default Re: Through Hole PCB repairs with miniature eyelets:

Technique that was succesfully used with MOD approval on one Radio was to utilise scrap boards, carefully removing the track needed and aralditing it in place on the board under repair. From memory the ends were soldered over . This was for single sided boards, where even the most careful re worker could lift tracks. More so on radios where a "field" repair had been attempted.
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Old 15th Jan 2019, 1:20 am   #7
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Default Re: Through Hole PCB repairs with miniature eyelets:

I have attempted Araldite in the past but the adhesive is not temperature resistant enough to be satisfactory and bubbles up & softens with soldering iron heat, the 24Hr version is better though than the 5 min version, but is still pretty poor. There is a high temperature low vapor resin for the task, but I'm not sure where to get that.
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Old 15th Jan 2019, 2:08 am   #8
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Default Re: Through Hole PCB repairs with miniature eyelets:

Commercially available through pcb hole interconnects are available and known as "via's" and are ideal for the repairs as outlined by Argus25.
They are a neat way of linking double sided board tracks where through hole plating cannot be replicated for any reason.

I have previously transferred reclaimed sections of the old single side copper foil track onto a damaged board as suggested by Oldcodger but have used superglue gel in preference to Epoxy but being careful not to inhale the fumes or allow it into my eyes.
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Old 15th Jan 2019, 3:54 am   #9
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Default Re: Through Hole PCB repairs with miniature eyelets:

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Originally Posted by VT FUSE View Post
Commercially available through pcb hole interconnects are available and known as "via's" and are ideal for the repairs as outlined by Argus25.
They are a neat way of linking double sided board tracks where through hole plating cannot be replicated for any reason.
I have these, made by RS, but unlike an eyelet they only spread over the pad just a little at the hole edges. So they are good if the pads are intact on the board, as they are on an initial home made dual sided pcb, but not any use if the pad has lifted on a damaged pcb.

There are commercial copper copper eyelet kits for pcb repair but they are costly, compared to the brass ones I used and some cheap tools made from pot shafts.

These are some cheap eyelets:

https://www.ebay.com/itm/M0-9-M2-5-C...53.m2749.l2649


This is a commercial pcb repair kit:

http://www.soldertools.net/pcb-repair-kit/

Also, commercial eyelet presses for pcb repair are expensive at $1795.00 and you have to buy the tool for each sized eyelet

http://www.circuitmedic.com/products/110-5202.html

Last edited by Argus25; 15th Jan 2019 at 4:03 am.
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Old 15th Jan 2019, 1:03 pm   #10
Nickthedentist
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Default Re: Through Hole PCB repairs with miniature eyelets:

Quote:
Originally Posted by Argus25 View Post
The technique would also be very helpful on damaged phenolic pcb's in vintage transistor radios. It was pretty easy to make the simple tools to do it.
Something similar was done during the manufacture of early transistor sets, to make it easier for the transistors to be replaced without damaging the board.
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Old 15th Jan 2019, 1:20 pm   #11
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Default Re: Through Hole PCB repairs with miniature eyelets:

Quote:
Originally Posted by Argus25 View Post
Look good. Do these have to have their length trimmed before fitting according to thickness of board?

Someone with a lathe could make a bit of money by running up some of those pot shaft tools and offering to members! We don't all have a lathe.

Mike
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Old 15th Jan 2019, 9:39 pm   #12
Argus25
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Default Re: Through Hole PCB repairs with miniature eyelets:

As noted in the article I posted, I initially used 3mm long eyelets, that required a small trim. The ebay link is to the 2.5 mm ones which are fine as they are and don't require trimming. Eyelets are super easy to trim though, with a simple metal plate and small file.

The main trick to getting it right is to just slightly flare the mouth of the eyelet with a tapered tool, prior to pressing it. I just used a small brass shaft and a couple of very very gentle taps from a small hammer. With copper eyelets, just a little force from the hand & tool is required to flare them, as they are much softer.
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Old 19th Jan 2019, 5:44 pm   #13
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Default Re: Through Hole PCB repairs with miniature eyelets:

Great idea, Hugo. Really practical and ingenious, thanks!
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Old 19th Jan 2019, 6:01 pm   #14
M0FYA Andy
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Default Re: Through Hole PCB repairs with miniature eyelets:

To install some tags recently, a similar task, I started the 'flare' with the point of a scriber tool, followed up with a small centre-punch.
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Old 8th Feb 2019, 2:21 am   #15
VT FUSE
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Default Re: Through Hole PCB repairs with miniature eyelets:

A quick thank you to Argus 25 for suggesting the eBay eyelets,today I took delivery of 200 of each of two sizes and they will be most useful,
A useful hint and also a nod in direction of where to order them.

Mike
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Old 11th Feb 2019, 9:55 am   #16
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Default Re: Through Hole PCB repairs with miniature eyelets:

Delco Radio used "eyelets" or as they called them "Griplets" in their car radios.
What a nightmare to track intermittents down in those sets.
The eyelet would develop a microscopic solder crack between the PC land and the board.
A truly evil production method.
We used to just run a short piece of wire thru the "Griplet" and solder each end to the PC land. It took a lot of time, but no callbacks on intermittents.
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