Changing heatsinks

[Karlos]

Hi,

I'm currently dragging an old Apollo 040 card out of retirement for my A1200. It's in a bad way but I reckon it could be made to live and breath again.

One of the nuisance factors is the old fan/heatsink. The old fan sounds like a motorcross bike and the heatsink is bonded to the chip.

I have a very low profile, (and quiet) 5V fan/heatsink  I'd like to install in its place, only marginally taller than the original heatsink.

Does anybody know a 'safe' way to remove the old heatsink? I'd rather not take a chisel to it :-)

[Doobrey]

Hi Karlos,
  I asked the same question a couple of weeks back on the Amiga hardware hacks Yahoo group.
 The only reply I got, was to put the Apollo in a plastic bag , suck all the air out, seal the bag up and put it in the freezer for 20 mins. :-o

 I haven`t worked up the courage to do it yet...I might forget about it in the freezer, and have it turn up as a pizza topping..
I know what you mean about the fan..that poxy heatsink is too small to properly take the screws to hold the fan firmly without vibrating..

[lorddef]

Superglue fails at extreme tempretures so as Doobrey says, freezing it should loosen the glue.  I used to superglue the tyres to the wheels of my radio controlled cars when I used to race them and the only way to remove them was to boil them up in a pan of water, thought I doubt doing the same would be good for your accelerator   :-P

You probably would be best to just use brute force though, if it's stuck with superglue it shouldn't be bonded too fast to it.

[Karlos]

Brute force, eh? I do have some scary visions of shattering the ceramic of the CPU however ;-)

I was thinking that I might be able to wedge it off...

[Karlos]

Hey, I got it off!!! :-D

@ Doobrey

I just got the heatsink off no problem. I simply prised it off with a pair of narrow tip pliers. Just gently ease the end vanes of the heatsink and voila :-)

-edit-

The only downside is that the nasty blue coloured glue stuff is still stuck to the CPU. I guess it's thermally conductive though, so I'm not too worried

-edit #2-

Now I just need to find a nice +5VDC line on the card I can tap for the fan. Either that or power it from a connector somewhere...

[lorddef]

how do you intend to affix the new heatsink now?

[Karlos]

With some thermal grease and a pair of small plastic clips ;-)

[Turambar]

Alchohol and cotton buds should remove the previous adhesive. And as for damaging the ceramic its pretty unlikely, i once took a drill to a dx33 and did nothing but blunt the drill bit :/

[lorddef]

Why cant you use the source that the old fan was wired to? is it 12v?

You would probably be best to just take the power from a molex connector on the psu if its in a tower, or from the floppy power connector if its a desktop.

[Karlos]

Yeah, the old fan was +12VDC. The card is going into a desktop 1200 (I already have a towered 1200 with BlizzPPC).

The fan I have is +5VDC, covers the whole CPU area and is much lower noise :-)

I am thinking to source a pair of connectors so that I can remove the card and simply 'unplug' the fan from wherever I choose to draw power (probably the floppy).

My old desktop (pre tower) had a pair of power connectors that fed power seperately to the motherboard and to the drives via a molex connector I fitted to the back of the case. The whole system was thus powered via two power cables from a 200W PSU. I might do something similar again :-)

[lorddef]

Just out of curiosity, is this the 040 board that you were going to sell on a while back?

[Karlos]

Indeed it is. I sent it to Vincent who had it for a bit but it tuned out to be wrecked and he returned it a while ago.

I wasnt able to test it myself since I had no desire to rip my 1200t apart for it so it sat idle for a bit.

I went home last week to visit the folks and grabbed a bunch of a1200 bits I had lying around to build myself a 1200 wedge again and thought I'd try the 040 card.

It is wrecked, but I think I know what is wrong with it (the cards boot ROM is physically damaged) so I'm trying to fix it...

-edit-

Incidentally, that's a good memory you have there matey ;-)

[lorddef]

You could stepdown the voltage from the onboard 12v source to 5v for your fan with a resistor, just use voltage/current = resistance.  It'll waste a little power, but not too much.

[Karlos]

Yeah, I guess, but I dont mind sourcing a 5VDC line from somewhere. A power regulator to step the voltage down might be a bit better, but I'm not sure what the waste is like. Probably more than the resistor...

[lorddef]

Most people say I have a photographic memory, it would help if I could have remembered the useless crap that I needed for some of my final exams, but I think beer deleted all that, oh well.