Hi. I had one of these and the insulation on the transformer windings later break down so I was thinking to pot it or enclose the transformer completely in resin. May I ask what value of the resistor you use for the feedback to the transformer and how many volts is your power supply? Thanks for the nice video.
Pretty helpful actually. For anybody preparing to buy one, stop. Buy three or 10 or something so when you screw up the first one, you can start over. :) I got a bag of these for $0.77/ea from Aliexpress. Armed with this video, you might get it working on the first try. I came here after screwing up two of them. :) - The filing of the enamel was a really good tip, helped me. The sandpaper just wasn't cutting it and you can't burn this crap off apparently. - Mr. Magoo magnifying glasses help. Definitely better to mount it with the wires coming from the top vs the bottom, as they give you a long length. Don't try to shorten the transformer wires, just file the enamel off the ends and solder the ends. Or you'll never solder it. Even with flux. - Resistor tied to pins is a good idea, just make sure you get a good solder there. I had to jiggle it so cold solder joint there somewhere. - Mine kind of whistles if I move it or blow air across the arc. I used dielectric tape (some green stuff) to hold the HV lines about a centimeter apart. - That transistor heat sink gets hot. Honestly might have been easier without the PCB.
The pads are for three things: 1. if the package is a glass fiber reinforced one 2. if the board is rated for vibration 3. if the board is rated for water incursion. Otherwise, you can get away with metal to metal just fine.
That's just not true... The sil pad is there to ensure good contact with the heat sink while providing electrical isolation between the heat sink and the transistor package. It is not uncommon to see the metal tab being connected to the emitter of the transistor. While the emitter often goes to ground {comma} it is not necessarily the case and thus you may end up with differing potentials between the emitter and the heat sink.
Hi. I had one of these and the insulation on the transformer windings later break down so I was thinking to pot it or enclose the transformer completely in resin. May I ask what value of the resistor you use for the feedback to the transformer and how many volts is your power supply? Thanks for the nice video.
Pretty helpful actually. For anybody preparing to buy one, stop. Buy three or 10 or something so when you screw up the first one, you can start over. :)
I got a bag of these for $0.77/ea from Aliexpress.
Armed with this video, you might get it working on the first try. I came here after screwing up two of them. :)
- The filing of the enamel was a really good tip, helped me. The sandpaper just wasn't cutting it and you can't burn this crap off apparently.
- Mr. Magoo magnifying glasses help. Definitely better to mount it with the wires coming from the top vs the bottom, as they give you a long length. Don't try to shorten the transformer wires, just file the enamel off the ends and solder the ends. Or you'll never solder it. Even with flux.
- Resistor tied to pins is a good idea, just make sure you get a good solder there. I had to jiggle it so cold solder joint there somewhere.
- Mine kind of whistles if I move it or blow air across the arc. I used dielectric tape (some green stuff) to hold the HV lines about a centimeter apart.
- That transistor heat sink gets hot.
Honestly might have been easier without the PCB.
The pads are for three things:
1. if the package is a glass fiber reinforced one
2. if the board is rated for vibration
3. if the board is rated for water incursion.
Otherwise, you can get away with metal to metal just fine.
That's just not true... The sil pad is there to ensure good contact with the heat sink while providing electrical isolation between the heat sink and the transistor package.
It is not uncommon to see the metal tab being connected to the emitter of the transistor. While the emitter often goes to ground {comma} it is not necessarily the case and thus you may end up with differing potentials between the emitter and the heat sink.
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Nichtmal annähernd ^^
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