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Re: Arcing in Mega STe PSU

Posted: Thu Nov 02, 2017 9:43 pm
by Pacman
I'm sold!
I couldn't find any shops selling sheet bakelite (oddly enough I came across a local companies producing electrical insulation materials, among them bakelite) so if you believe those thin overhead transparency/laser printer sheets are good enough (this is what you're referring to when you talk about Polyester OHP, right?) I think I'll just take the easy route and be done with it. Perhaps two sheets for some added stiffness.
Yes, I'm a little paranoid when it comes to electrical safety, seeing those burn marks shown earlier in this thread ;)

Re: Arcing in Mega STe PSU

Posted: Thu Nov 02, 2017 9:59 pm
by exxos
OHP should be fine as Ingo says. I'm more paranoid ;)

2mm doesn't stand up to 8,000 volts, and 8,000 volts can arc under insulation oil over the top of the insulations sheets for 2 inches.. :roll: :lol: :twisted:

https://www.exxoshost.co.uk/IMPULSE2015 ... ycoil.html

Not sure this is anything to do with your thread though, :lol:

Re: Arcing in Mega STe PSU

Posted: Fri Nov 03, 2017 11:21 am
by IngoQ
Pacman wrote:
Thu Nov 02, 2017 9:43 pm
those thin overhead transparency/laser printer sheets are good enough (this is what you're referring to when you talk about Polyester OHP, right?)
Yep, exactly. Just make sure, they are really polyester and 0.13mm or thicker.

Re: Arcing in Mega STe PSU

Posted: Fri Nov 03, 2017 11:23 am
by IngoQ
exxos wrote:
Thu Nov 02, 2017 9:59 pm
2mm doesn't stand up to 8,000 volts, and 8,000 volts can arc under insulation oil over the top of the insulations sheets for 2 inches.. :roll: :lol: :twisted:
Yeah, high frequency AND high voltages is a whole different thing, as Tesla discovered ;)

Re: Arcing in Mega STe PSU

Posted: Fri Nov 03, 2017 11:59 am
by Pacman
IngoQ wrote:
Fri Nov 03, 2017 11:21 am
Pacman wrote:
Thu Nov 02, 2017 9:43 pm
those thin overhead transparency/laser printer sheets are good enough (this is what you're referring to when you talk about Polyester OHP, right?)
Yep, exactly. Just make sure, they are really polyester and 0.13mm or thicker.
I tried to find out but can't find the specifications. The exact one I have is Nobo OHP transparency film -laser printer film (33633740). I also found them at Amazon and there it says they weight 100g (though I'm not sure how many sheets that refers to...).

I originally bought them for printing PCB layouts with my laser printer for making my own PCBs from old magazine layouts.

Re: Arcing in Mega STe PSU

Posted: Fri Nov 03, 2017 12:09 pm
by IngoQ
Pacman wrote:
Fri Nov 03, 2017 11:59 am
I tried to find out but can't find the specifications.
It's a little gamble. My guess is, that all OHP sheets are Polyester, but I don't know that for certain. If they are intended for a laser printer, they obviously are heat proof to a certain degree.

If you want to be on the safe side, order sheets with a clear specification. That said, I am sure, your sheets will improve the insulation over air in any case, just how much is the question.

In addition, I would cut the pins on the lower side of the PCB as short as possible, to not have these long electrodes as you appearantly had before.

Re: Arcing in Mega STe PSU

Posted: Sun Nov 12, 2017 4:37 pm
by Sausageinabun
I completed the recap on my STE PSU this afternoon, and mine, Mitsumi SR98, does have a plastic insulation sheet.

I bought one of Chris's recap kits, and it all went as smooth as silk. Even drilling out the rectifier holes a tad only cost me the one drill bit ;)

I've run the it for several hours now and it is showing none of the earlier sysmptoms I had noticed. I also carried out the Video Fix, and the slight ghosting I had beforehand is now gone.

So all done and dusted, and I am a very happy camper :D

Re: Arcing in Mega STe PSU

Posted: Sun Nov 12, 2017 9:39 pm
by exxos
Sausageinabun wrote:
Sun Nov 12, 2017 4:37 pm
I've run the it for several hours now and it is showing none of the earlier symptoms I had noticed. I also carried out the Video Fix, and the slight ghosting I had beforehand is now gone.

So all done and dusted, and I am a very happy camper :D
Nice one! Thanks for keeping us updates! :cheers: