I am trying to remove the white silicone sealant around the two large caps in attached photo. It's still rock-hard after trying the following:
1. 2-hour soak of IPA. (Not really effective, because the IPA quickly evaporates.)
2. Nail varnish remover.
3. Lighter fluid.
4. De-Solv-it (for silicone).
Apart from grinding it off, which would be difficult, does anybody have another proven solution, please?
Many thanks.
1. 2-hour soak of IPA. (Not really effective, because the IPA quickly evaporates.)
2. Nail varnish remover.
3. Lighter fluid.
4. De-Solv-it (for silicone).
Apart from grinding it off, which would be difficult, does anybody have another proven solution, please?
Many thanks.
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I think you mean 'silicone' sealant, but anyway....
Are you sure it's silicone? 'Rock hard' would suggest some other type of adhesive.
Possibilities could include a hot-melt type glue, or perhaps a polyurethane or epoxy- based product. Good luck in getting any of those loosened with chemicals - you'll need to cut them somehow.
Those caps 'look' to be OK. Is there a reason to remove/replace them?
Hi, VG.
Thanks for the feedback.
This Nakamichi amp is 27 years old. I popped a couple of the smaller caps and they measured 1/2 of rated capacitance. I checked Nelson Pass' post at the following thread and decided to replace all the Nichicon capacitors with Panasonic.
http://www.diyaudio.com/forums/pass-labs/218270-nakamichi-pa-5-upgrades.html
Have a great day.
It looks like an awkward place to get tools into, to cut that adhesive.
Good luck! Please let us all know what works - it's a bit easier if you don't mind destroying the old caps, I suppose.
Good luck! Please let us all know what works - it's a bit easier if you don't mind destroying the old caps, I suppose.
It might be worth trying a penetrating lubricant, or even baby oil (messy!) , around the edges of the sealant, where it meets the board .
Keep in mind that some lubricants can damage plastic , contact/ lock/ gun cleaner or such usually won't .
Use very sparingly, let it soak a while and test it in one spot first .
Keep in mind that some lubricants can damage plastic , contact/ lock/ gun cleaner or such usually won't .
Use very sparingly, let it soak a while and test it in one spot first .
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Thanks everyone for your kind help.
I already desoldered the capacitor poles, but can't remove the capacitor without breaking the PCB. (The sealant is glued to the capacitor case.)
Heated the sealant with an old 60W soldering iron. It made a furrow in the sealant but it quickly hardened again.
I'll try Horst's idea tonight and if that doesn't work, I'll Dremel it tomorrow. (Can't buy C4 in Japan...)
Cheers!
I already desoldered the capacitor poles, but can't remove the capacitor without breaking the PCB. (The sealant is glued to the capacitor case.)
Heated the sealant with an old 60W soldering iron. It made a furrow in the sealant but it quickly hardened again.
I'll try Horst's idea tonight and if that doesn't work, I'll Dremel it tomorrow. (Can't buy C4 in Japan...)
Cheers!
Can you cut down the sides of the plastic sleeve to expose the metal casing? Maybe most of the glue is gripping the bottom of the sleeve and you can at least remove the cap first. If that works than you only have the plastic and glue to clean up.
Good luck and keep us posted.
BillWojo
Good luck and keep us posted.
BillWojo
Heated the sealant with an old 60W soldering iron. It made a furrow in the sealant but it quickly hardened again.
Try a hot air gun. Heat the board from the bottom. The "glue" will soften before the solder melts..
Try a hot air gun. Heat the board from the bottom. The "glue" will soften before the solder melts..
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Chisel is the operative word. A small wood chisel might work wonders, especially if you don't care about the caps you're removing - why should you?
Success..
Succeeded using BillWojo's suggestion. I completely removed all the old solder with a good solder sucker and desoldering braid, but I had to use a 60W iron to dislodge the caps.
The residue sliced off with a thin razor blade.
Thanks everyone for all your help.
Succeeded using BillWojo's suggestion. I completely removed all the old solder with a good solder sucker and desoldering braid, but I had to use a 60W iron to dislodge the caps.
The residue sliced off with a thin razor blade.
Thanks everyone for all your help.
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Heat gun.. will soften, even melt potting goops.
Try not to burn the rest of the bits on the PCB though.
Try not to burn the rest of the bits on the PCB though.
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