[tomb]

If you want to mess with acid baths and lethal DC rectifier currents, then DIY-anodizing might be a good choice. Otherwise, I'd leave it alone.

Aluminum Anodizing at home - DIY aluminium Anodising

We used to use sulfuric anodizing a lot at Lockheed, but it was not for the faint-hearted. They also invented a resin-coating finish that's used on alloy wheels these days, from what I understand.

 

[aphexii]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif If you want to mess with acid baths and lethal DC rectifier currents, then DIY-anodizing might be a good choice. Otherwise, I'd leave it alone. Aluminum Anodizing at home - DIY aluminium Anodising We used to use sulfuric anodizing a lot at Lockheed, but it was not for the faint-hearted. They also invented a resin-coating finish that's used on alloy wheels these days, from what I understand.

What's a good DIY project if the chance of death isn't involved?

 

[linuxworks]

Quote:

Originally Posted by aphexii /img/forum/go_quote.gif What's a good DIY project if the chance of death isn't involved?

such has been said about deep-frying turkeys.

it sounds good, in theory; but I would not want to do it at home!

 

[linuxworks]

question about the heatsinks and the solder posts, on them.

is it *really* necessary that the heatsinks be soldered? as long as they rest squarely on the pcboard and the leads to the transistors are well soldered - and if the screw holds tight enough on the to-220 tab, then why is that not good enough? the leads from the to-220's go straight down and so they pretty much ensure the HS isn't going anywhere.

I hate the thought of having to unsolder them. perhaps I'll tack-solder them lightly but I'm not sure its such a great idea to douse the holes with solder...

I'm curious why the solder heatsinks were spec'd instead of screw ones? or did I miss the place that talked about the option to choose either? I simply ordered from mouser based on the BOM and didn't really give much thought to the solder-post vs screw type.

the ones with the posts in them, do they come out, easily? maybe I can convert the mouser ones I got into being screw-style if I remove those force-fit solder posts?

 

[rds]

Quote:

I hate the thought of having to unsolder them. perhaps I'll tack-solder them lightly but I'm not sure its such a great idea to douse the holes with solder...

I tack my heatsinks in place like this:

It takes the strain off the to220 part, but the heatsink is still easily removable.
Just heat up that ribbon of solder and use a solder pump to suck it away.

Also, that solder tack is surprising strong. Chances are you'd crack the board before breaking that joint.

 

[linuxworks]

cool. sounds like a plan.

I was going to do it just like you did.

still, I think if I was paying attention, I would have ordered the screw style instead. solder type is more for automated wave-soldering machines, isn't it? diy is not quite the same and so screws would have been a better choice for the 'oops' that often happen on a one-off assembly we do at home.

 

[rds]

Can you link to these screw style ones? I don't think I've seen them before.

 

[linuxworks]

the ones that amb spec's for his b22 are screw-type (as I call it). you either use metal screws or you tap threads in the existing holes. but there are no solder posts on those.

(I'm doing a b22 build almost at the same time as the minimax)

 

[tomb]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif cool. sounds like a plan. I was going to do it just like you did. still, I think if I was paying attention, I would have ordered the screw style instead. solder type is more for automated wave-soldering machines, isn't it? diy is not quite the same and so screws would have been a better choice for the 'oops' that often happen on a one-off assembly we do at home.

Is everything supposed to be for wave-soldering?

I don't think so. Yes, pinned heat sinks are difficult to remove ... but then again, they're not supposed to be removed, anyway. There are issues with tapped heat sinks, too. The pinned heat sinks were chosen on purpose and have served well for several hundred MAXes and MiniMAXes. However, it's DIY and you're welcome to choose the parts you wish at any time, of course.

EDIT: If you go back far enough in the history, the M3 was purposely chosen for pinned heat sinks, too - the non-pinned heat sinks were considered an issue in the early days. Pinned sinks are simpler, require less skill to install properly, are more plentiful, and cheaper.

rds's method seems a simple solution if you're afraid of soldering the heat sinks in permanently.

 

[linuxworks]

I'm curious, what is the drawback with the screw type?

is it the need for tapping or that tapping could be off-center?

I don't have taps/dies but a strong screw seems to be all I need to start some threads, as long as the screw is stronger than the heatsink material. or use sheet metal screws, maybe.

I realize that normally you don't have to remove them once you install them, but what if you blow a part that needs replacing? it just seems from a serviceability POV, the more things you can easily and non-destructively remove - the better.

at the least, I would suggest a note in the bom to give the user a choice. it really is worth mentioning and giving alternate part #'s for the screw type.

 

[linuxworks]

has anyone tried these things? they are called 'slow color change leds':

on ebay, you search for 'slow color change led' and this comes up.

I have one in a usb xmas tree gadget; it cycles between R,G,B and shades between them. slow transition (hence the 'slow color change' name).

I'm thinking of trying it under the tube sockets. is that going too far?

I did place an order so I'll find out anyway. apparently the controllers and 3 separate led's are in the led casing so you only supply 3v or so to them and they cycle on their own between the various colors. kinda neat in a bling kinda way

 

[aphexii]

Interesting, very curious to see how those come out... The only thing that might annoy me is if they change at different speeds so the colors don't match up.

On a side note, is the technology built directly into the LED itself? Or does it use a separate controller to handle the color change?

 

[aphexii]

Almost forgot to mention. Turns out there is a local anodizing shop about 5 minutes from my house. He can do a black anodize for $4.75, but has a minimum order of $125

I asked if he could just maybe throw mine in with someone elses order when they needed a black anodize and he said no.

So it looks like I'm back to FPE only, silver or black.

 

[linuxworks]

I broke a led off my usb xmas tree (lol) and its JUST a single led with 'guts' inside. I'll take a photo later on. you can see the 3 led 'bases' and the controller chip (I think) inside.

its JUST 2 wires and you have no control over timing. most likely they each will have a mind of their own. it may not be what people want..

I might go back to using discrete leds or 4wire leds (3 colors but no 'chip'). that way I really can parallel the 2 leds and have the colors be 100% in sync. problem then is to find a simple/cheap outboard controller to PWM control the voltages (3 of them) to the leds and create a nice pattern

I've seen PIC chip circuits do this but its more effort than I'm onboard for.

 

[aphexii]

So i'm tossing around the idea of making an acrylic sandwich of the faceplate.

Anodized Aluminum with the Logo and Volume Knob cut out ---> Brushed/Frosted acrylic in the middle ---> solid piece of aluminum on the back with holes cut for the LED's to shine though.

Ideally, the strategically placed LED's would light up the Acrylic from the back, and the holes on the front would allow it to glow from behind. Primarily through the logo and around the volume knob.