Garbz
Headphoneus Supremus
- Joined
- May 19, 2004
- Posts
- 3,573
- Likes
- 15
Well Duh. Of course it's important to think ahead. I had no idea what I was thinking or why I wasn't thinking when building my new Gilmore PSU, as this has been the biggest headace of the past week.
The idea was simple. Put all active components on the side of the board and bolt them all to the same heatsink. Easy yes? NO!
- I finished designing the board put all the components on and was very happy with myself. Ordered my heatsink and ... All of a sudden I was left with a big heavy heatsink in one hand and nothing to mount it on. Great I can bolt it onto the components, but then the entire kilo of heatsink would be supported by 20 IC pins. Bad idea.
- I pondered over this and though easy. I'll take a right angle bracket and mount the components onto it, then i'll mount it onto the heatsink. Since there's no where above the pcb to mount it i'll mount the PCB with legs onto the bracket. That worked initially. I put down my latest creation and ... wobble!!!! Now one side of the board was 2mm higher then the other.
- Easy solution for this one cut a small section of metal drill a hole and use it as a washer. No problem there. But there was a problem just as I started feeling prowd of myself. Out of all the active components one of the opamps was right in the centre of one of the heatsink fins.
- Ok use the sandwhich method. drilled 3 holes either side of the components and one in the middle. Since the drill travels alot and since I had no more sharp bits I used a 5mm bit for the corresponding holes in the heatsink. That worked reasonably well, so I went back to the 3.5mm bit and drilled three holes into a the final layer of the sandwhich. DOH!
- The holes were no loner aligned since I measured the hole without the parts on and forgot to take into account the actual package of the regulator and opamp. So now the holes were about 1 mm off and I can't bolt my sandwhich together. Finally I decided to simply whip out the dremel and replace my carefuly mismeasured holes with slots so I could mount it whatever way I wanted to. Worked.
- Back to the heatsink now thoes holes didn't line up. At this stage I whipped the drill out and moved the holes a bit. Since they were large to begin with it was only off by half a mm.
- So on to mounting it all together I can't get my screw driver in behind the caps. Ok easy just put the bolt in the other side and the nut on the board side. <language is getting more colourful now> The bolt fell straight through the heatsink. The nut is larger then 5mm but the head of the bolt is just slightly smaller. So i put a horribly bent and hackedup washer on the other side and finally get it in.
- Now I'm sitting there really happy with myself, I look over and see an empty pack of silicon washers and plastic screw spacers. DOH. There's a giant metal piece across all active componets now shorting various things together. The silicon washers are on the bottomside of the parts where they belong.
- So off to dismantling the sandwhich and I decided to put the plastic spacers in but wait. They are of course deeper then the active components, and the components would no longer make a solid conneciton with the bracket.
- I whipped out my knife and begin halfing the spacers so I can use them as an extra layer. Slipped.
I cut my finger!!!!!!!!!.
- With language that could easily sware people out of christianity I finally re-assemble the sandwhich. Grabbed a coffe and started writing this.
God this thing looks nasty:
People think ahead before you do something stupid!!!
The idea was simple. Put all active components on the side of the board and bolt them all to the same heatsink. Easy yes? NO!
- I finished designing the board put all the components on and was very happy with myself. Ordered my heatsink and ... All of a sudden I was left with a big heavy heatsink in one hand and nothing to mount it on. Great I can bolt it onto the components, but then the entire kilo of heatsink would be supported by 20 IC pins. Bad idea.
- I pondered over this and though easy. I'll take a right angle bracket and mount the components onto it, then i'll mount it onto the heatsink. Since there's no where above the pcb to mount it i'll mount the PCB with legs onto the bracket. That worked initially. I put down my latest creation and ... wobble!!!! Now one side of the board was 2mm higher then the other.
- Easy solution for this one cut a small section of metal drill a hole and use it as a washer. No problem there. But there was a problem just as I started feeling prowd of myself. Out of all the active components one of the opamps was right in the centre of one of the heatsink fins.
- Ok use the sandwhich method. drilled 3 holes either side of the components and one in the middle. Since the drill travels alot and since I had no more sharp bits I used a 5mm bit for the corresponding holes in the heatsink. That worked reasonably well, so I went back to the 3.5mm bit and drilled three holes into a the final layer of the sandwhich. DOH!
- The holes were no loner aligned since I measured the hole without the parts on and forgot to take into account the actual package of the regulator and opamp. So now the holes were about 1 mm off and I can't bolt my sandwhich together. Finally I decided to simply whip out the dremel and replace my carefuly mismeasured holes with slots so I could mount it whatever way I wanted to. Worked.
- Back to the heatsink now thoes holes didn't line up. At this stage I whipped the drill out and moved the holes a bit. Since they were large to begin with it was only off by half a mm.
- So on to mounting it all together I can't get my screw driver in behind the caps. Ok easy just put the bolt in the other side and the nut on the board side. <language is getting more colourful now> The bolt fell straight through the heatsink. The nut is larger then 5mm but the head of the bolt is just slightly smaller. So i put a horribly bent and hackedup washer on the other side and finally get it in.
- Now I'm sitting there really happy with myself, I look over and see an empty pack of silicon washers and plastic screw spacers. DOH. There's a giant metal piece across all active componets now shorting various things together. The silicon washers are on the bottomside of the parts where they belong.
- So off to dismantling the sandwhich and I decided to put the plastic spacers in but wait. They are of course deeper then the active components, and the components would no longer make a solid conneciton with the bracket.
- I whipped out my knife and begin halfing the spacers so I can use them as an extra layer. Slipped.
- With language that could easily sware people out of christianity I finally re-assemble the sandwhich. Grabbed a coffe and started writing this.
God this thing looks nasty:
People think ahead before you do something stupid!!!
