Open Wirebond Display Protection?

[Chris S.]

Sorry if this has been discussed before. I'm sure I read something a while back but can't find it now.

Is there anything out there that can be used to protect the open wirebonded led displays which over time can become detached from the pcb tracks either due to age or vibration. Any information would be greatfully received.

[retroleds]

I would suggest clear-ish epoxy. 24 hr. type is best for this, as there is the most time for bubbles to work themselves out of the epoxy -unless you have a vacuum chamber and pump to de-gass the epoxy. Mix the epoxy, wait an hour or two and look for any larger bubbles, which you may be able to drag out of the mix(and swirl gently whilst mixing the epoxy in the first place). Then drip gently onto each digit - slightly to the side of the digit, tipping to let it flow through the wire bonds, which will avoid air being trapped there. Larger air bubbles are distracting if they end up over a display segment but I would say think twice about digging a bubble out, as wet epoxy, like water, refracts/bends the visuals and could cause you to do irrepairable damage.

Do not use nail-polish: it is solvent based, which means it will attack the circuit board and components while wet, and will shrink as the solvent dries off, frequently leading to dead segements; presumably, due to wire bonds being pulled from their [tiny] connection points.

Do not power up until epoxy is thoroughly dry - it conducts electricity to some degree while uncured.

Thank you for thinking about protecting another vintage display.

[Chris S.]

Thanks Ed.

Are there any specific products you would recommend or steer clear of fo that matter?

[retroleds]

I like Devcon brand, but mainly just for the tip, whick seems to keep the part A & B separated better on a long term basis. That and I found a place that sells for about 1/2 or retail if you buy 12 packs in one shot....that's about 1 years supply for me, at most.

[Chris S.]

Sorry, been away for a while. Thanks again I'll look into the brands you mentioned (probably have to source an equivalent in the UK).

Seems to me you're doing an awful lot of preserving there. Do you automatically seal any open wirebonds during your repairs or only when requested?

[funkyguy]

hi retroleds..
which of theses products would you reccomend?
cheers.
FG
http://www.lawson-his.co.uk/scripts/det ... duct=30035

[retroleds]

hi retroleds..
which of theses products would you reccomend?
cheers.
FG
http://www.lawson-his.co.uk/scripts/det ... duct=30035

None of those....get 24 hr. hardening, or at LEAST the one hour. 5 minute stuff will end up with many bubbles trapped in it that would have risen and popped in even the first 1/2 hr. of the 1 hour stuff's hardening time.