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sd cartridge for 7800?


metzger130

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Is removing the POKEY from Ballblazer typically a challenge?

 

 

You have to de-solder 40 pins.

Desoldering is not for the inexperienced. I bought a desolder gun a couple years back and used it a couple different times, adding a DSP-1 chip to a super Everdrive, removing the NES CPU to install a CopyNES, and transplanting mask ROMs from a dead Panic Restaurant to a Home Alone 2 donor. It requires extreme patience. If you rip out a pin, and the chip needs this pin to function, then it is pretty much toast.

 

There's also a really guetto way to do it. Some people use a gas stove top to heat up the underside of a board until the solder melts, then flip it over and the through hole chips fall out.

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Trivia: A lot of copies of 2600 Elevator Action are no longer functioning, because Sean used a blow-torch to remove the SARA chips from Dig Dug carts.

 

If you want to remove a chip, fine, but do not rely on it working afterwards.

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Desoldering is not for the inexperienced. I bought a desolder gun a couple years back and used it a couple different times, adding a DSP-1 chip to a super Everdrive, removing the NES CPU to install a CopyNES, and transplanting mask ROMs from a dead Panic Restaurant to a Home Alone 2 donor. It requires extreme patience. If you rip out a pin, and the chip needs this pin to function, then it is pretty much toast.

 

There's also a really guetto way to do it. Some people use a gas stove top to heat up the underside of a board until the solder melts, then flip it over and the through hole chips fall out.

 

With a hakko desoldering pump you are golden. But not everyone wants to spend $200 on one. The stove method is for sad times.

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The heat from the torch destroys the chips. Thats only if you want to replace the chips and throw them in the garbage.

I have 8 ram chips to replace on a colecovision.

What if I cut the legs off the ram chips with a pair of sidecuts then heated the remainder of the legs one by one with a soldering iron and needle nose pliers to pull them out?

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The heat from the torch destroys the chips. Thats only if you want to replace the chips and throw them in the garbage.

I have 8 ram chips to replace on a colecovision.

What if I cut the legs off the ram chips with a pair of sidecuts then heated the remainder of the legs one by one with a soldering iron and needle nose pliers to pull them out?

I've done that before. It works fine and you don't risk damaging the board.

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That's got to be the stupidest thing I've ever seen. :lolblue:

Agreed, that guy is a very lazy ghetto idiot mf'er. Heat kills electronics, he's reducing the life of his chips, scorching his board, cooking the green coat, charing any smaller components. I would expect that pcb to not last long. I would never do that.

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With a hakko desoldering pump you are golden. But not everyone wants to spend $200 on one. The stove method is for sad times.

The $200 option must be nice. I think I spent ~$20 on mine at Radio Shack. It's just a bulb sucker built into the iron. Stick the eyelet over the hole to heat the joint and release the bulb. It helps to apply fresh flux to the contacts before sucking.

 

I've tried using manual pumps and braid and while good for cleanup or removing excess solder / bridges, both are pretty much useless for completely removing through hole chips with more than 2 or 3 leads.

 

Trivia: A lot of copies of 2600 Elevator Action are no longer functioning, because Sean used a blow-torch to remove the SARA chips from Dig Dug carts.

 

If you want to remove a chip, fine, but do not rely on it working afterwards.

I got lazy and used a butane soldering iron (remove the tip to access torch mode) to remove the DSP1 from a second SNES cart when I got my Super Everdrive v2. I think I used Indy racing. The torch caused the two layer PCB to delaminate, but the DSP1 chip worked just fine afterwords. I will probably not use the torch method again.

 

Not sure the exact temperature that silicon breaks down, but water boils at 100C, solder melts at 200C, and I think the silicon survives up to around 300C or so. So there is a safety margin, but the torch method is ill advised because parts of the PCB may likely reach much hotter than the 200C melting point due to uneven heating.

 

So for instance using a toaster oven to heat the entire PCB evenly to 200C ballpark (about 375F for lead solder, 400-425F for newer ROHS compliant boards) until the chip drops out probably will not kill it. Best to remove any electrolytic caps first as they may explode.

 

Even Krikzz uses a toaster oven for applying SMT components, as some parts are no longer manufactured as through hole. I would not recommend using the same oven that you use to cook with however due to lead contamination.

 

I recently toured a PCB fab facility during a field trip for my community college, and they do run the entire PCB through an oven. The pick and place robot pulls the SMT components from a ribbon and applies solder paste and sticks them on the board. It consists of solder metal ground to a powder and mixed with flux as a binder, as opposed to the rosin solder wire normally used for hand work. The paste acts as a weak adhesive while the board moves down the conveyor before it enters the oven. Otherwise the pieces would slide off with the slightest vibration. The oven heats the PCB evenly and the solder paste melts underneath the components, so obviously heating the entire chip to the melting point of solder does not incur damage.

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I believe the blue flames are over 1500C, so the guy using the stove can expect to cook the board traces pretty good. I'm guessing chip packaging and board might actually insulate the silcon ok. There could be damage from the extreme temps the pins will reach. Maybe the connections to the internal wires fail?

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The problem is the insulation doesn't do anything for conduction of heat through the leads, and he holds it on that flame for a good long time. Bonus points awarded for doing it with a coin cell that might have easily exploded in his face.

 

The usual el-cheapo method to depopulate ICs is to use a hardware-store heat gun. At least with that method you can actually see when the solder has become shiny and liquid, but its still not recommended if you care about the parts you're trying to remove.

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That video is really old, the gun has been discontinued, I think I paid $170 for that one.

 

I use this one now: http://www.hakkousa.com/detail.asp?PID=5247&Page=1

That's nice, but expensive. I just got a cheap Radio Shack brand 40w iron with the sucker bulb built in. It works well enough but occasionally the bulb does not completely suck the entire solder out and I have to reapply flux and try again or attempt to loosen the leads with a needle nose pliers.

 

That's awesome! Things like this are why I can't wait for the Concerto. :D

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