What on earth is this?
What on earth is this?
So I recapped the TT PSU, was waiting only for PC111 opto to make the job complete. Arrived today, so hooray to desolder the old one... I swear to all Gods of Electronics, I didn't do anything else than hot-aired the PCB:
It can't be scrubbed off by isoprohyl alcohol, it seems to be possible only to melt (?) it. It really behaves like some kind of tough chocolate but looks like something burned at the same time. I didn't noticed anything falling off (the pad really looks like it did but I don't think so) so I'm left with mouth wide open wondering what the hell just happened there?Re: What on earth is this?
probably just red hot flux which "exploded" during manufacture would be my first guess. Some flux sets like epoxy!
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: What on earth is this?
Perhaps I should have specified that this happened out of the blue, i.e. the PCB had nothing even remotely similar there before. I simply started desoldering and it appeared like a plague.
Bad news - the pad is indeed gone.
Good news - fortunately that pin is not connected.
Still, never seen anything like this. What could cause it? Air too hot?
Bad news - the pad is indeed gone.
Good news - fortunately that pin is not connected.
Still, never seen anything like this. What could cause it? Air too hot?
Re: What on earth is this?
ITS A Spider!! Nope, look up and right a little bit is the missing pad from the OPTO where the spider is setting. Looks like what ever happened is involved with the desolder since the pad is decoupled.mikro wrote: ↑Thu Nov 15, 2018 1:44 pm So I recapped the TT PSU, was waiting only for PC111 opto to make the job complete. Arrived today, so hooray to desolder the old one... I swear to all Gods of Electronics, I didn't do anything else than hot-aired the PCB:
IMG_20181115_143749.jpg
It can't be scrubbed off by isoprohyl alcohol, it seems to be possible only to melt (?) it. It really behaves like some kind of tough chocolate but looks like something burned at the same time. I didn't noticed anything falling off (the pad really looks like it did but I don't think so) so I'm left with mouth wide open wondering what the hell just happened there?
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Re: What on earth is this?
It looks like hot air scorching. My experience with hot air and these old fibreglass boards is that they de-laminate very easily, and are very prone to scorching. Looks like maybe too hot plus some flux going nuclear and setting like stone. Lucky that pad isn't in use.
Personally I much prefer wick to hot air for these old boards.
Personally I much prefer wick to hot air for these old boards.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
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800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: What on earth is this?
Very true as well!rubber_jonnie wrote: ↑Thu Nov 15, 2018 2:14 pm It looks like hot air scorching. My experience with hot air and these old fibreglass boards is that they de-laminate very easily, and are very prone to scorching.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: What on earth is this?
Lesson learned. I just wish it wasn't exactly this way but could have been worse.
Re: What on earth is this?
Note that burnt FR4 (PCB material) can get conductive. Since the black spot is also between two pads of the opto-coupler that are used, make sure it doesn't impact the regulation of the PSU.