Arcing in Mega STe PSU

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Pacman
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Re: Arcing in Mega STe PSU

Post by Pacman » Thu Nov 02, 2017 9:43 pm

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 ;)
Mega STe | MonSTer with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESSC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

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exxos
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Re: Arcing in Mega STe PSU

Post by exxos » Thu Nov 02, 2017 9:59 pm

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:
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IngoQ
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Re: Arcing in Mega STe PSU

Post by IngoQ » 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.
Ingo :geek:

“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” - Antoine de Saint-Exupéry

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IngoQ
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Re: Arcing in Mega STe PSU

Post by IngoQ » Fri Nov 03, 2017 11:23 am

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 ;)
Ingo :geek:

“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” - Antoine de Saint-Exupéry

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Pacman
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Re: Arcing in Mega STe PSU

Post by Pacman » Fri Nov 03, 2017 11:59 am

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.
Mega STe | MonSTer with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESSC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

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IngoQ
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Re: Arcing in Mega STe PSU

Post by IngoQ » Fri Nov 03, 2017 12:09 pm

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.
Ingo :geek:

“Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” - Antoine de Saint-Exupéry

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Sausageinabun
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Re: Arcing in Mega STe PSU

Post by Sausageinabun » Sun Nov 12, 2017 4:37 pm

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
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exxos
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Re: Arcing in Mega STe PSU

Post by exxos » Sun Nov 12, 2017 9:39 pm

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:
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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