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I Think I Just Killed My TI (was Reset Button)

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My TI-99 (a beige non-v2.2 model) has a push button on the side the served as a reset button. This worked really well until I was putting in my F18a and accidentally yanked out one of the two wires going to it. I'd like to wire it back up, but I have no idea where the wires should go (I didn't put in the button, it came with it). Is there an easy place on the TI motherboard to wire up a reset button? I'm not very handy with a soldering iron, but I think I can solder a wire or two.

 

I'll take a look at where the one still attached wire is going tonight.

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My TI-99 (a beige non-v2.2 model) has a push button on the side the served as a reset button. This worked really well until I was putting in my F18a and accidentally yanked out one of the two wires going to it. I'd like to wire it back up, but I have no idea where the wires should go (I didn't put in the button, it came with it). Is there an easy place on the TI motherboard to wire up a reset button? I'm not very handy with a soldering iron, but I think I can solder a wire or two.

 

I'll take a look at where the one still attached wire is going tonight.

 

 

Wire from 9900 pin 6 to switch to gnd

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Well that didn't work. I'm pretty sure I just killed my TI. I think I may have accidentally bridged pins 5 and 6 and then totally screwed it up even further by trying to get that solder out. The TI is not giving me a picture and is making a nasty buzzing/held beep noise and that's it. I'm not sure if it's worth sending it out to be fixed or just getting a new one. Can anyone fix?

 

What I did tonight is a crime against humanity and soldiering.

 

ti99_1.jpg

 

ti99_2.jpg

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A friend is going to take the solder blob out. We'll see if I fried anything or not.

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Use solder wick (desoldering braid) next time to draw out the excess solder. Bridged pins happen all the time, at least when I solder ;) ... it's all about knowing what to do next :) .

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What were you soldering with, a blacksmith's iron? ;-) ;-)

 

Shorting pins 5 and 6 should have no ill effects other than keeping the processor in perpetual reset. Remove the solder blob and all should be well.

 

Another place you could connect the reset button is across capacitor C606, which is the large capacitor near the grey crystal. Far easier to access. See this picture [http://www.avjd51.dsl.pipex.com/ti/images/console_32k_ram_modification_fitted.jpg] and follow the grey cable on the left, which goes to my reset button.

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I have a VERY crappy Radio Shack iron that has a wobbly tip. I really need to invest in some better equipment, that's part of the problem. I never do because I always screw stuff up when I solder so I figure what's the point. It's a self perpetuating cycle of suck.

 

Hopefully I didn't do any damage trying to get the excess solder out. I don't see any traces under where I was scraping. Still, I'm seriously embarrassed at what I did. :skull:

 

What's a good cheap iron with a smallish tip? I guess I'd also need to find a cheap solder wick.

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For the future...

 

I have found that cleaning the through hole out and running the wire next to the pin is a pretty sound method (don't forget to resolder.)

 

There isn't anything wrong with RS equipment although some love to rip on them. A plunger type solder sucker will help you in your endeavors (available from..... wait for it..... RS ;-)...

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I always thought the RS iron had too large of a tip for soldering small wires but that could just be my inexperience. The tip is seriously wobbly though, I need to fix that.

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I always thought the RS iron had too large of a tip for soldering small wires but that could just be my inexperience. The tip is seriously wobbly though, I need to fix that.

 

You can get smaller tips. Is yours a 40 Watt by chance?

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You can get smaller tips. Is yours a 40 Watt by chance?

 

I'm not sure, I'd have to check. It was whatever cheap one they were selling in the store. :)

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What's a good cheap iron with a smallish tip? I guess I'd also need to find a cheap solder wick.

 

Do a search on eBay for "Antex 18W", and see what sort of price they are in your part of the world. That's a pretty decent iron, with power and tip size suited for TI work.

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I usually prefer solder suckers over wick, especially for something like this but either should work. You may have better luck adding a bit more solder to the bridge at first, to get things flowing better.

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Good news/bad news situation. Turns out my system is fine, it's the F18a I fried. I put the F18a in another system and it did the same thing my original did (solid tone and no picture). When I put the old video chip back in I got the standard beep (I assume it's working, but I don't have a non-vga monitor handy to look).

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Good news/bad news situation. Turns out my system is fine, it's the F18a I fried. I put the F18a in another system and it did the same thing my original did (solid tone and no picture). When I put the old video chip back in I got the standard beep (I assume it's working, but I don't have a non-vga monitor handy to look).

 

Dude... the feels...

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Good news/bad news situation. Turns out my system is fine, it's the F18a I fried. I put the F18a in another system and it did the same thing my original did (solid tone and no picture). When I put the old video chip back in I got the standard beep (I assume it's working, but I don't have a non-vga monitor handy to look).

Talk to Matthew, I'm sure he'll help you out!

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Talk to Matthew, I'm sure he'll help you out!

Yeah I sent him a PM. I'm sure he can fix it for me.

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I replied to your PM.

 

As for soldering, having a right sized tip with the proper amount of heat is very important. A certain Wattage does not mean a specific temperature, which is the main problem with the lesser expensive fixed-size irons. For lead-based solder you want a tip temperature of about 625 degrees F. Always use a rosin-core solder and NEVER an acid core. Make sure you don't buy the lead-free solder for working on old lead-solder circuits, lead and lead-free solders do not mix. Also, *clean* joints are critical. Old computers are very dirty and a little cleaning with 99.9% alcohol (not the 91% stuff you get a the store) will go a long way. Nothing replaces practice though.

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I'm not sure what 'technique'some people use, but I've had the best experience with using a toothpick to apply a little flux on the IC chip lead I intend to solder. Prep the wire with solder ahead of time, when ready to solder just press the prepped wire onto the fluxed lead and then apply the iron. After about a second, remove the iron and hold the wire for another second or two. You'll never get a solder bridge.

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I replied to your PM.

 

As for soldering, having a right sized tip with the proper amount of heat is very important. A certain Wattage does not mean a specific temperature, which is the main problem with the lesser expensive fixed-size irons. For lead-based solder you want a tip temperature of about 625 degrees F. Always use a rosin-core solder and NEVER an acid core. Make sure you don't buy the lead-free solder for working on old lead-solder circuits, lead and lead-free solders do not mix. Also, *clean* joints are critical. Old computers are very dirty and a little cleaning with 99.9% alcohol (not the 91% stuff you get a the store) will go a long way. Nothing replaces practice though.

 

I would add that the solder diameter will also make a difference. For most of my chip-work I use a spool that is slightly thicker than thread combined with a relatively small tip. For through-hole work I use a larger diameter. The spools from Radio Shack are probably 2x-3x thicker than necessary, which contributes to the blobbing effect and over-feeding solder into the through-holes (which can create short-circuits under the components or sockets).

 

Also a small toothbrush can aid in cleaning the joints prior to soldering and for cleaning up the leftover flux resin upon completion.

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