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That awful "yellow glue" - How to remove it?

Sunnysky

Jul 15, 2016
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Since seeing the photos, there is no exposed copper , you can get away with any clear silicone sealant. So RTV is no longer necessary, just use that after testing no more arcs.

Solder mask is an epoxy based insulator on bottom side but surface contaminants must be removed as much as possible.
 

Brenda S

Aug 7, 2016
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@Sunnysky: So, if I understand you correctly, you're saying any clear silicone sealant has a much higher impedance than the yellow/tan glue that began to conduct (and won't break down over time the way the glue does), so it will be safe to use any clear silicone sealant to moisture-seal the grooves I cut into the glue? Also, only "electronics grade" silicone RTV will be safe in places where it would touch multiple exposed conductors (component leads, exposed copper traces, etc.) that aren't already wired together?

Regarding the "long shelf life" of RTV that you mentioned in a previous post, were you referring to the life of unopened tubes of RTV? I was wondering how long the unused portion of the RTV will be useable, after I open the tube to use a little on this project. (In some other contexts, I've seen the phrase "shelf life" used to mean the life of unopened products.)

Is there any reason not to trust the cheapest "electronics" grade RTV advertised at Amazon? The cheapest I've found so far is $10.19 for 3 oz of GC Electronic Grade Silicone Sealant / Adhesive 19-155:
https://www.amazon.com/GC-Electronic-Silicone-Sealant-Adhesive/dp/B004SPJN6K
One of the reviewers wrote: "The only issue I have is that the cap does not prevent the tube from drying out very quickly and it is best if used within a few days."

Another brand is MG Chemicals Non Corrosive Translucent 1-Part RTV Silicone Adhesive Sealant, 85 ml Tube for $12.76.
https://www.amazon.com/MG-Chemicals-Corrosive-Translucent-Silicone/dp/B005T8R6LY
The two products are hard to compare pricewise because one lists its volume (85 ml) and the other lists its weight (3 oz). However, the shipping weight of the 85 ml tube is listed as 3.2 oz, placing an upper limit on the weight of the 85 ml of RTV.
 

Brenda S

Aug 7, 2016
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Aug 7, 2016
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Many thanks, Sunnysky and KJ6EAD, I think you've given me enough to decide how to proceed (unless someone speaks up quickly with a contrary opinion):
1. Use isopropyl alcohol to clean dust & debris off the power supply board; let dry.
2. Verify still no arcs and that the board produces voltages.
3. Use electronics grade silicone RTV to moisture-seal the grooves & scratches I made in the glue; allow time to set.
4. Verify still no arcs and that the board produces voltages.
5. Reassemble monitor.
 

Brenda S

Aug 7, 2016
13
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Aug 7, 2016
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Update: I ordered the electronics grade Silicone RTV sealant made by MG Chemicals from Amazon, which arrived 8 days ago. I followed the steps outlined in message #24 above, and my monitor has been working fine ever since. The label on the Silicone RTV has some scary health warnings, though: "Suspected of damaging fertility in the unborn child. May cause an allergic skin reaction. Obtain special instructions before use. Do not handle until all safety precautions have been read and understood. Avoid breathing vapors/mist. Contaminated work clothing should not be allowed out of the workplace. Wear protective gloves/eye protection..." Etc. I'm unsure whether I'd have bought it if I'd known. Certainly not without additional research.
 

bigone5500

Apr 9, 2014
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Update: I ordered the electronics grade Silicone RTV sealant made by MG Chemicals from Amazon, which arrived 8 days ago. I followed the steps outlined in message #24 above, and my monitor has been working fine ever since. The label on the Silicone RTV has some scary health warnings, though: "Suspected of damaging fertility in the unborn child. May cause an allergic skin reaction. Obtain special instructions before use. Do not handle until all safety precautions have been read and understood. Avoid breathing vapors/mist. Contaminated work clothing should not be allowed out of the workplace. Wear protective gloves/eye protection..." Etc. I'm unsure whether I'd have bought it if I'd known. Certainly not without additional research.

I think that is so they don't get sued...
 

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