Newbie replacing a video DAC chip! Save the 1200

[AmigaDunc]

WooHooo

Finally got lucky and found a VP101-3BA 44PLCC video DAC at AnalogicComputers in Surrey, UK.

Awesome, just got to figure out how to remove the old one and install the replacement without destroying anything.

Dont even own a soldering iron!

[Daedalus]

Yikes. If you're planning to do it yourself and haven't done this sort of work before, get plenty of practice in on less precious boards than the A1200. Try removing and replacing the chips on an old network card, modem or similar. With the right tools and technique it's a relatively straightforward job, but there's a high risk of significant damage to the board if it's not done correctly. You'll need a hot air rework station, and ideally a suitably-sized PLCC nozzle at the minimum. For fitting the replacement chip, I prefer to use solder paste and a suitable stencil and hot air, but I know other people prefer to drag-solder with plenty of flux.

But if this isn't something you're competent with and you don't plan to get the correct tools and experience to be able to do it, I'd suggest bringing the board and chip to someone with the necessary gear and skills.

[Snoopy1234]

Retropassion UK do repair work if you're unable to. I know soldering doesn't always go smoothly for novices. To do it properly you need the right gear; solder wick, heat gun, flux, solder and that paste stuff if it's a SMD IC. Keen eyesight and steady hands too.

[Jope]

Whoa. Definitely don't do this on the A1200 on your first try.

But if you are going to attempt it anyway and don't have experience of PLCC rework, then you should not attempt to get the old chip off intact. Especially if your tools are a soldering iron and solder wick. Removal of old surface mount parts is where PCBs usually get ruined when beginners try.

Instead of an intact removal, I recommend getting the tiniest pair of diagonal cutters, cutting each leg off the bad chip right next to the chip package, ever so gently so that they don't twist to the side at all, and then remove the legs one by one by heating with your soldering iron and swiping them off. Hardly any force is to be used, if the leg isn't moving, the solder is still solid and you might end up cracking a trace/pad off the board instead.

Then the rest is as "normal", wick up the old solder, add flux, dab solder on your iron tip and drag solder the new chip in. Which is also easier said than done if you've never done it before or your tip shape is not that well suited to drag soldering.

Manually soldering PLCC pin-by-pin is also doable for a patient person, but you'll end up with a ton of solder bridges and some pins will inevitably not make contact and you will have to redo them. :-)

[AmigaDunc]

Haha thanks guys for your comments.
Yep having got the motherboard out for a closer look, I had not appreciated the madness on the underside and the proximity of the chip legs to one another. I've done basic electronics and soldering but this is definately beyond my rookie capabilities.

Open to anyone who has adequate experience and would be willing to undertake the work? for a price ofcourse

I am in West Sussex but happy to send it anywhere in UK?

Thanks

[qz3fwd]

Send it to Dr Chris Edwards from YouTube fame. He does free repairs but it might take months….

[amigakit.com]

@AmigaDunc

Welcome!

We sell the chip here: https://www.amigakit.com/video-adv10...t-p-12665.html

We can also replace it with our in house repair service.

Hope this helps!

[AJCopland]

AmigaDunc

try asking
https://www.retropassion.co.uk/
or as they've already said
https://www.amigakit.com/

both do repair work, especially if you've already got the replacement chip

[offog]

Analogic themselves also still do repairs, according to their web site. I appreciate this testimonial is a bit out of date, but they replaced the video DAC in my A1200 in 1996 and it's still working fine!