PbF and eyelets

8 of 9 eyelets stayed on the component on desoldering, the duff one stayed in the pcb, its pin neatly sliding out of the eyelet.

I will render an opinion here based on my experiences with conventional lea d-containing solder of differing natures.

a) Non-Eutectic solders will solidify in a non-linear fashion as it cools. b) My experience with 60/40 and 50/50 solders with wires is that the coolin g is often based on the wire as it is a heat-sink. c) Dynaco equipment uses a lot of eyelets set in circuit boards. d) Using solders as described above, on more than one occasion I have gotte n visually excellent connections that simply twirl in the eyelet, as the so lder cooled (dumped heat into the wire) so fast that the shrinkage pulled i t away from the eyelet before it was actually solid.

This is purely anecdotal.

Today, I use only truly eutectic solders on my electronics (37/63 lead/tin) - with a very few exceptions, when for one reason or another I need to use silver bearing solder. In those cases, I use 96/4 tin/silver, and great ca re not to move anything as it cools.

Peter Wieck Melrose Park, PA

I had an eyelet problem 30 years ago on my Philips CD player. I couldn't fix it, so I sent it to Philips Repair. I worked at an authorized service center at the time. The sent it back saying they could not fix it. I mentioned it to a fellow tech and he said, "let me look at it". He put a wire through each eyelet and soldered both sides. That corrected the problem. Mikek

a via ?

Well, it's been over 30 years so it could have been vias, but I recall it as eyelets. I still have it I guess I could open it up. Naw, to much trouble to get it out of the closet. Mikek

I suppose part of the problem, the pins are square cross-section , not round. Then localised stressing edges for tinpest to develop. Remedial action will start by grinding back to an axial surface on all such pot pins, on the solder side of the pcb before resoldering. Then what other components will be eyeleted as well will need such attention, the main electros yes, minor electros will they be eyeleted , 1W and above Rs also, difficult to visually tell. I suppose the rule is anything big is likely to be eyeleted, plus any component resource with smaller pins.

If you can thread wire through, I'd call those vias.

en

lead-containing solder of differing natures.

ls.

oling is often based on the wire as it is a heat-sink.

otten visually excellent connections that simply twirl in the eyelet, as th e solder cooled (dumped heat into the wire) so fast that the shrinkage pull ed it away from the eyelet before it was actually solid.

tin) - with a very few exceptions, when for one reason or another I need to use silver bearing solder. In those cases, I use 96/4 tin/silver, and grea t care not to move anything as it cools.

Motorola had their "famous" Placir printed circuits in the 60s, and they we re notorious for connection problems between the top and bottom layers. Th e only solution to permanently repair these was to hard wire the top to bot tom.

GE in the 70s had a line of TVs that used double sided boards with hollow g riplets crimped through the board and covered with a thin layer of solder, and these would develop a dozen or more gimpy connections. Flexing the mai n board would cause all sorts of color, sync, brightness, video, sound issu es etc. Resoldering them was difficult because the boards would out-gas bad ly when the griplets were heated causing cold joints. Instead of hand wiri ng the 50 or more griplets, I solder one side thoroughly feeding in lots of solder, turn the board over and remove the excess solder that came through , resolder that side thoroughly, and turn it over again and reflow a third time. The outgassing usually stopped by the second pass. They never came ba ck after that.

He put a wire through each eyelet and soldered both sides. "

I am not straight on this eyelet thing. Does that mean the plated through h oles ? If it is like a rivet type thing they used to be called griplets.

They used them in some TVs with two sided boards that were not plated throu gh holes. They used to break free and wreak havoc.

Then we got the plated through holes without anything in them. What your bu ddy did might be called "pinning". Turns out some of the Dolby boards on th e Sansui 9090DB went bad this way some audiophiles consider this pinning to be an essential part of the restoration process.

It seems that on some boards the eyelets or griplets simply forestall the p roblem, not prevent it.

A good dialect word for the appearance of PbF - claggy, a conflation of clumpy and slaggy

We learned to cookem. Seriously, lay the iron on it and watch it bubble for a while. Some of them eventually stopped bubbling but some didn't. Those that didn't were usually sufficiently cooked to work.

I remember those AB chassis'. Now, they wouldn't even be considered for repair or anything like them. Even a flat screen that size today, if it is not fixed in five minutes it goes into the dumpster.

But that was then.

Some boards from the 70s used eyelets for their vias. They would be pressed into place, and over the years corrode enough to become intermittent.

Speaking of vias: the first coin operated video game - Computer Space - had a buss style motherboard (with sub-boards that held the logic) that was double-sided but they didn't plate the holes through so they put in tiny wires and soldered those top and bottom! I've also seen other early game boards that had plated through vias, but the holes were offset top/bottom and sometimes there was just a tiny bit of copper actually carrying the signal/current. Those were fun to troubleshoot when the copper corroded and several connections were lost.

John :-#)#

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Eyelets are a PITA whatever solder you use.

A couple of monitor manufacturers used them for the flyback transformer pins to prevent dodgy soldering resulting in a fierce arc that burns a hole in the board.

Solder wetting round the edges of the eyelets was often worse than the dodgy soldering, and tended to cause the very problem it was supposed to prevent.