tvtext pin assignment
sharpie
Posts: 150
I have a question since I made a mistake and broke a pin(13) off the chip(Q44) as I was soldering the last one before testing.....· Is there a way to tell the tvtext object that the starting pin is 12, the next is 11 and the last is 14?· the line below 'tv_pins :=' and so on... I'm not sure I'm grasping how that works entirely...· Is there a way I can add a couple variables for the other two pins?
PUB start(basepin) : okay '' Start terminal - starts a cog '' returns false if no cog available setcolors(@palette) out(0) longmove(@tv_status, @tv_params, tv_count) tv_pins := (basepin & $38) << 1 | (basepin & 4 == 4) & %0101 tv_screen := @screen tv_colors := @colors okay := tv.start(@tv_status)
Comments
How is your prop mounted? Is is soldered right to the board, or in a socket?
This is goofy, but I've had to do it in the past. When you break a pin off, there is some metal still exposed, but nearly flush with the packaging. Take a sharp box knife, or something similar, and scrape away the packaging to expose some of the metal stub. Take some flux and rub it on that area, being sure to get the metal bit covered. A light scrape or two with some sand paper before applying the flux helps.
Then comes the potatohead solder blob method. With your iron warm, apply solder and flux until you get a nice blob on the end. If you need to, insert some material between the board and the chip, that can be removed. Then brush the blob by the broken area of the chip. Wait to cool, then do it again. You will build up a small protrusion of solder that can then have something attached to it. I use a fine strand of wire. After the first coupla passes, it helps to blow lightly while brushing the blob by. You want some of the solder in the blob to stick, but not heat the solder attached to what's left of the pin.
If you need a smaller blob to work with, wrap some fine wire around the tip of your iron, while cool, and cut it to a length that makes sense. Use fine grit sandpaper to prep the wire, heat the iron, then tin the wire, just as you would a new soldering iron tip. Then build up a blob on that to work with, and use it like a solder paint brush.
From there it's fairly easy to bring that fine bit of wire down to the board or socket and make the connection.
If it's a socket, one can insert a pin or piece of wire from something else, into the socket. Do the scrape to expose some of remaining pin stub. Bend the wire, so that it contacts that stub and the small spring force left in the wire holds it there. Apply flux, then brush the blob past to make a better connection. This works with a board too. Just insert the wire, have it protrude through the board, to a height that makes sense where getting contact at the pin stub makes sense, and solder.
I'm almost reluctant to post this here among so many veterans, but surely somebody has broken a pin or two right? What did you pros do, besides suck it up and repurpose remaining pins, or get another chip?
Post Edited (potatohead) : 6/17/2007 7:42:06 PM GMT
Potatohead, thanks for the suggestion but I was soldering to the QFP packaged pchip. Getting in there with solder, wire and an iron was hard enough.. I mounted the chip to the board with a drop of superglue. and used wire wrap wire to do the dirty work. I'm not really concerned with peoples opinions of me after breaking a pin, it happens.. especially when trying something as nutty as this at 3 or 4 am.. I just hate to trash the board, chip and everything else because I knocked off a single pin
(I'm not particularly worried either. Stuff happens!)