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Modding Colecovision is a pain in the butt


7800fan
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I don't know if it's my specifc system or if it's common but I originally planned to use the hot air to loosen and remove chips (it worked for Atari computer as seen on that youtube video) but for some idiotic reason Coleco employees thought to bend every single pins of every chips to make sure it didn't move during wave soldering.

 

I tried to how air but I needed brute force to unbend 16 pins at once, and I risk bending or breaking the PCB while it's hot. So I had to do the old snip pins and desolder one at a time.

 

The connector was also in rather tight. I was able to remove the 2 rivets completely but again hot air didn't work. I ended up dremeling half of the connector off (parallel to the board) so I could pry the rest of the plastic out, then desolder and remove one pin at a time.

 

These needless difficultities resulted in 3 lifted pads requiring me to repair with jumper, and some more troubleshooting to resolve black screen of death, somehow Data D6 was cut somewhere. CPU and cart connector were connected. The BIOS, 2 ram chips, and video chip all still had D6 but somewhere between that 2 sets the data line was cut. Took me a while of probing to find out which line got broke and jumpered it.

 

I also cleaned the power switch until it was shiny and put it back together.

 

Finally got my Colecovision working again, and no more fuzzy screen Still to do: the annoying 14 seconds bios wait and the AV mod. I looked, the original BIOS is also soldered in with bent pins so I'd have to snip those out as well.

 

What idiot bends all the IC pins? Just 2 on opposite corners would have been enough!!

 

PS my Atarimax SD cart showed up today along with the new connector so I can load controller test ROM and go through 20 or so controllers I've been finding in the last decades to see what works and what needs works.

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I have done a few Colecos and yes the sheer amount of chip legs is awful. I use a temperature controlled soldering iron and a spring activated metal solder pump. Its a simple device that works really good for this application. I use flush side cutters and cut the legs off of the chips first and then solder off the legs.

 

That is what works best for me.

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I was able to remove the BIOS safely. I used the iron to melt solder and bent each pins straight. Then I used the hot air to remove the entire chip. My hot air is one of those Hakko clone with variable temp and variable nozzle and is perfect for making small SMD project, removing a lot of components at once, or when dealing with huge heat sinks like braid soldered to thick RF shield.

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Oh yeah forgot to mention, soldered in 28 pin sockets and bios back in, it still works. I have not changed the jumper as I don't have EPROM yet.

 

I checked the controllers I had laying around, only 2 works 100% (on both controller ports). I know CV ports are not the problem. The other 7 controllers I found (and I have more somewhere) has various issues. All of them either has missing direction and/or fire button. All of the keypad are 100% working. So need to open the non-working controllers, check the contacts, clean em, whatever else I need to do, then hope it works.

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The heating element of bulb type desoldering iron isn't really designed for continuous air flow, is there something to boost the heat to compensate for constant cooler air flowing in the tip?

 

I have an older Radio Shack bulb tool that's been sitting getting dusty because it sucks badly compared to either hot air station or plunger sucker.

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