Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will need only two, three centimeters to cover.

By the way, mobo and hard disk bought! The exact one in the photo linked from search engine but I still can't find any specs or manual of it even on the classic website where I usually find easily every jumper configs of these mobo. Few info about it even if it seems it was a usa company with a well specified brand/model of it. But anyway I've seen from an high resolution mainboard image there're not many jumpers anyway but the cache ones.. I suppose it may or not be able to automatically switch to the socket cpu. In an older thread in this forum someone had this mobo but from that thread images it had no cpu soldered so it is not clear how will work if a cpu will be inserted.
I'm not going to risk desoldering the on board 386 even if sure it'd seems to be easier than soldering it of course.

The only photo of the same mainboard on a web page found is here http://redhill.net.au/b/b-93.html looking for "38606".

It's the only page found with a photo of the mainboard and some info. The socket 386 has in the center hole pcb some passive yellow components installed so i'd suppose it's prepared for a cpu to be installed.
And the words on the pcb are MG-38606 Rev: 2.0 MG Technologies USA.

386SX wrote on 2020-06-08, 08:53:

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will […]
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Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will need only two, three centimeters to cover.

By the way, mobo and hard disk bought! The exact one in the photo linked from search engine but I still can't find any specs or manual of it even on the classic website where I usually find easily every jumper configs of these mobo. Few info about it even if it seems it was a usa company with a well specified brand/model of it. But anyway I've seen from an high resolution mainboard image there're not many jumpers anyway but the cache ones.. I suppose it may or not be able to automatically switch to the socket cpu. In an older thread in this forum someone had this mobo but from that thread images it had no cpu soldered so it is not clear how will work if a cpu will be inserted.
I'm not going to risk desoldering the on board 386 even if sure it'd seems to be easier than soldering it of course.

I link to whole mainboard photo found online because it's exactly like it. The socket 386 has in the center hole pcb some passive yellow components installed so i'd suppose it's prepared for a cpu to be installed.
And the words on the pcb are MG-38606 Rev: 2.0 MG Technologies USA.

For some reason the link to the pic wouldn't load for me, even after a bit of url hacking.
I presume it's the board on this page then CTRL+F "MG 38606", is this correct?

Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

Tetrium wrote on 2020-06-08, 12:14:

386SX wrote on 2020-06-08, 08:53:

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will […]
Show full quote

Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will need only two, three centimeters to cover.

By the way, mobo and hard disk bought! The exact one in the photo linked from search engine but I still can't find any specs or manual of it even on the classic website where I usually find easily every jumper configs of these mobo. Few info about it even if it seems it was a usa company with a well specified brand/model of it. But anyway I've seen from an high resolution mainboard image there're not many jumpers anyway but the cache ones.. I suppose it may or not be able to automatically switch to the socket cpu. In an older thread in this forum someone had this mobo but from that thread images it had no cpu soldered so it is not clear how will work if a cpu will be inserted.
I'm not going to risk desoldering the on board 386 even if sure it'd seems to be easier than soldering it of course.

I link to whole mainboard photo found online because it's exactly like it. The socket 386 has in the center hole pcb some passive yellow components installed so i'd suppose it's prepared for a cpu to be installed.
And the words on the pcb are MG-38606 Rev: 2.0 MG Technologies USA.

For some reason the link to the pic wouldn't load for me, even after a bit of url hacking.
I presume it's the board on this page then CTRL+F "MG 38606", is this correct?

I don't know why yes that's it, I've edited the post and linked directly the only site found with the search engine having the only identical image and some info of the mainboard I'll receive.

Tetrium wrote on 2020-06-08, 12:16:

Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

I think it is because I've seen on other mobo how easily those traces can really detach from the mobo if a layer doesn't "push" them on the pcb. And they are thin also and the possibility of humidity and short circuit when working on the mobo is too high imho. If I'm correct the green mask layer has more than one reason to be there for protection of the trace and everything that can get in touch with its metal if uncovered.

386SX wrote on 2020-06-08, 12:33:

Tetrium wrote on 2020-06-08, 12:16:

Anonymous Coward wrote on 2020-06-08, 07:45:

From what I have heard, you can use clear nail polish to cover up exposed PCB traces.

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

I think it is because I've seen on other mobo how easily those traces can really detach from the mobo if a layer doesn't "push" them on the pcb. And they are thin also and the possibility of humidity and short circuit when working on the mobo is too high imho. If I'm correct the green mask layer has more than one reason to be there for protection of the trace and everything that can get in touch with its metal if uncovered.

Good call. I will keep this in mind when I'm gonna browse through my old parts again and keep an eye out for these issues more.

386SX wrote on 2020-06-08, 12:29:

Tetrium wrote on 2020-06-08, 12:14:

386SX wrote on 2020-06-08, 08:53:

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will […]
Show full quote

Really isn't it conductive in some way? I've seen that there're those green mask uv solder paint but not really cheap and I will need only two, three centimeters to cover.

By the way, mobo and hard disk bought! The exact one in the photo linked from search engine but I still can't find any specs or manual of it even on the classic website where I usually find easily every jumper configs of these mobo. Few info about it even if it seems it was a usa company with a well specified brand/model of it. But anyway I've seen from an high resolution mainboard image there're not many jumpers anyway but the cache ones.. I suppose it may or not be able to automatically switch to the socket cpu. In an older thread in this forum someone had this mobo but from that thread images it had no cpu soldered so it is not clear how will work if a cpu will be inserted.
I'm not going to risk desoldering the on board 386 even if sure it'd seems to be easier than soldering it of course.

I link to whole mainboard photo found online because it's exactly like it. The socket 386 has in the center hole pcb some passive yellow components installed so i'd suppose it's prepared for a cpu to be installed.
And the words on the pcb are MG-38606 Rev: 2.0 MG Technologies USA.

For some reason the link to the pic wouldn't load for me, even after a bit of url hacking.
I presume it's the board on this page then CTRL+F "MG 38606", is this correct?

I don't know why yes that's it, I've edited the post and linked directly the only site found with the search engine having the only identical image and some info of the mainboard I'll receive.

My guess is that it was done by disabling hotlinking in order to save bandwidth.

Tetrium wrote on 2020-06-08, 12:44:

386SX wrote on 2020-06-08, 12:33:

Tetrium wrote on 2020-06-08, 12:16:

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

I think it is because I've seen on other mobo how easily those traces can really detach from the mobo if a layer doesn't "push" them on the pcb. And they are thin also and the possibility of humidity and short circuit when working on the mobo is too high imho. If I'm correct the green mask layer has more than one reason to be there for protection of the trace and everything that can get in touch with its metal if uncovered.

Good call. I will keep this in mind when I'm gonna browse through my old parts again and keep an eye out for these issues more.

Meanwhile I've already bought one of those uv green mask pcb paint tube that should be enough for more applications cause only a few amount should be needed to make a thin flat layer. I've seen some youtube video how they use it with new PCB and it's impressive how good the result is.

Example: https://www.youtube.com/watch?v=Vj_cdBZO1Tk

Tetrium wrote on 2020-06-08, 12:16:

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

Mostly to prevent corrosion (especially if you live anywhere near salt water bodies) and any accidental shorts. Nail polish (doesn't have to be clear one) is ususally fine, even the modern nail-friendly ones are. A piece of good sticky tape will also do fine but many of those will peel off due to heat, leaving behind sticky residue. It really needs to be quality tape to last.

Deunan wrote on 2020-06-08, 13:13:

Tetrium wrote on 2020-06-08, 12:16:

Just out of curiosity (and maybe it's a stupid question), but is it actually necessary to cover up exposed PCB traces?

Mostly to prevent corrosion (especially if you live anywhere near salt water bodies) and any accidental shorts. Nail polish (doesn't have to be clear one) is ususally fine, even the modern nail-friendly ones are. A piece of good sticky tape will also do fine but many of those will peel off due to heat, leaving behind sticky residue. It really needs to be quality tape to last.

I'd not use tape on those because if eventually the glue is too strong and it's needed to take the tape off for some work (change the battery for example), traces themself might come off too depending on how much exposed they are. There's the specific uncovering liquid for it I think.
I was wondering if the nail polish actually protect for conduction or short circuit. I understand it sure make a layer on them but what about conduction?

copper oxidizes, you need to prevent that by not exposing it to air

same reason we plate contacts in tin, gold, etc.

386SX wrote on 2020-06-08, 13:26:

I was wondering if the nail polish actually protect for conduction or short circuit. I understand it sure make a layer on them but what about conduction?

I've yet to find one that would be conductive - but if you want to be sure, just paint a bit of wood, let it dry, than measure yourself.
BTW drying takes a lot of time on PCB because there isn't any easy way for the volatile part to evaporate. It's best to leave it be for a day or two at room temperature. I don't recommend heating to make it dry faster, tends to have a weaker bite and can even peel off on it's own.

Deunan wrote on 2020-06-08, 14:52:

386SX wrote on 2020-06-08, 13:26:

I was wondering if the nail polish actually protect for conduction or short circuit. I understand it sure make a layer on them but what about conduction?

I've yet to find one that would be conductive - but if you want to be sure, just paint a bit of wood, let it dry, than measure yourself.
BTW drying takes a lot of time on PCB because there isn't any easy way for the volatile part to evaporate. It's best to leave it be for a day or two at room temperature. I don't recommend heating to make it dry faster, tends to have a weaker bite and can even peel off on it's own.

That's why considering the price of the specific paint liquid fixable by UV rays, I think I'll use this one because it seems under the sun it takes only minutes (at least looking at the video linked above) to fix on the pcb. I am sure the nail polish will cost just as much. 😁

Interesting, I found that someone here had a board having a pcb layout that looks identical to the one I'll receive soon even if a different brand/model and it's this one:

Re: Tex's ultimate 386 project!

The QD-U386DX as far as I can tell is identical! Finally some more possible info to look for. Even if the modern battery should be a later mod cause from other images it had the usual Ni-Cd one.