Solder pad problem
8 messages · 2008-01-10 → 2008-01-11 · Yahoo Group era · View archive on archive.org
Participants: Adam Trionfo, Bill Dunlop, Rory McMahon, M. Emrah Oral
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. My Attempt at the Composite Upgrade
Adam Trionfo · Thu, 10 Jan 2008 10:51
I attempted the TS 2068 composite upgrade yesterday. My computer is currently NOT in working order (because their is no voltage regulator installed-- more on that later). Here are some things that I DID: avoid them:
1) Do NOT use replacement part NTE966 for the 78M12 voltage regulator. I bought this at a local electronics store. This is electronically the same, but the leg form factor is just too big.
2) No not use lead-free solder.
3) Do not install the voltage regulator backward. (Like I need to tell you this!)
Here are some additional details about my attempt:
Attempt One - Removing the Old and Installing the New Voltage Regulator
After I desoldered the original 78L12 voltage regulator I noticed that the legs on the new voltage regulator (part #NTE966) just would not fit through the holes; they were at LEAST twice as wide as the hole. I decided to use my trusty Dremel to fix this. I ground away at the legs until they fit through the though-holes. I soldered the legs in place using lead-free solder (which turned out to be a mistake), but because I had ground away at the legs and exposed the metal underneath I could not get the solder to flow well (lead-free solder doesn't flow nearly as well as lead solder to begin with). On one leg in particular the solder just would NOT adhere to the regulator's leg. I decided that I would have to replace the voltage regulator, but I first wanted to check to see if the system worked at all with the bad solder joints. It did work, but the video was TERRIBLE (which is to be expected). So, at least I knew this upgrade would work with the correct parts.
Attempt Two - Removing the Previously Installed Voltage Regulator
I removed the NTE966 voltage regulator. It came out cleanly, though it did take some persuasion. What did NOT come out fine was the solder. As I've already stated, lead-free solder does not flow well at all. In the end solder-wick and my de-soldering iron (with the "sucking bulb") could not get the solder removed. I had to resort to scraping it out with a knife (which would come back to haunt me later).
Attempt Three - Installed a REAL 7812
I went out to Radio Shack and bought the 7812 voltage regulator (it's still the same part number as it was twenty years ago: 276-1771). I came home and soldered it into place, this time using non-lead-free solder. It was SO much easier to install with this solder. No problem at all. Then I tried it. I turned it on. Nothing. I took a look and, DAMN!, I inserted the voltage regulator backwards! What a STUPID thing to do!
I removed the 7812, hoping to save it and just turn it around and try again. This time the part just would not come out. Finally, I had to cut the legs and take them out one at a time using needle-nose pliers. This quick upgrade was turning into a nightmare. I was frustrated and mad. I SHOULD have just stopped and called it a night. But NO... I just HAD to finish. My idea at the time was to solder some new legs onto the 7812 and start again. Except in my haste when removing one of the legs I pulled a solder-pad free. BAD, BAD news.
The Aftermath
I'm stuck where I ended yesterday. I have a non-working TS 2068... which I hope I can repair. I have not bought another voltage regulator at Radio Shack because, with the solder-pad gone, there is no way to solder the compoenet to the board.
Your Help Needed
I've never had to fix a solder-pad that has lifted from the main board (or ANY board). I found some information about this on the Internet, but I don't have the parts to do it. I've also found some kits, but they are EXPENSIVE (and don't include the tools needed-- just the parts). My question for all of you is this: how do I fix a solder-pad that has lifted from the board?
Adam
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2. Re: [ts2068] Solder pad problem
Bill Dunlop · Thu, 10 Jan 2008 12:21
--- Adam Trionfo <[email]> wrote:
> Your Help Needed
>
> I've never had to fix a solder-pad that has lifted from the main board (or ANY board).
> I found some information about this on the Internet, but I don't have the parts to do
> it. I've also found some kits, but they are EXPENSIVE (and don't include the tools
> needed-- just the parts). My question for all of you is this: how do I fix a
> solder-pad that has lifted from the board?
Adam>
Adam
Only one time (in my wild impetuous youth) have I tried to fix a pad on a board. I had
some success using a hypodermic syringe (from a relative with diabetes) and a carefully
placed drop of "super-glue" under then a wait of about two days. In my case the traces
were OK but you should check carefully first.
Remember: YMMV and no guarantees so, good luck. Hope this helps.
Bill
3. Re: [ts2068] Solder pad problem
Rory McMahon · Thu, 10 Jan 2008 15:43
Adam,
Bill's hint will probably work on most simple boards.
For pads connected to other layers, it won't. You will probably need a
schematic and a multimeter to make sure all connections are made. Use
small wire (wirewrap) to make the necessary missing connections.
Rory
--- Bill Dunlop <[email]> wrote:
>
> --- Adam Trionfo <[email]> wrote:
>
>
> > Your Help Needed
> >
> > I've never had to fix a solder-pad that has lifted from the main
> board (or ANY board).
> how do I fix a solder-pad that has lifted from the board?
> Adam>
>
>
> Adam
>
> Only one time (in my wild impetuous youth) have I tried to fix a pad
> on a board. I had
> some success using a hypodermic syringe (from a relative with
> diabetes) and a carefully
> placed drop of "super-glue" under then a wait of about two days. In
> my case the traces
> were OK but you should check carefully first.
>
> Remember: YMMV and no guarantees so, good luck. Hope this helps.
> Bill
>
4. Re: [ts2068] Solder pad problem
Rory McMahon · Thu, 10 Jan 2008 15:49
Ok,
Did see the whole post for this...
For power connections you will need thicker wire than wirewrap.
Thanks.
Rory
--- Rory McMahon <[email]> wrote:
> Adam,
>
> Bill's hint will probably work on most simple boards.
>
> For pads connected to other layers, it won't. You will probably need
> a
> schematic and a multimeter to make sure all connections are made. Use
> small wire (wirewrap) to make the necessary missing connections.
>
> Rory
>
> --- Bill Dunlop <[email]> wrote:
>
> >
> > --- Adam Trionfo <[email]> wrote:
> >
> >
> > > Your Help Needed
> > >
> > > I've never had to fix a solder-pad that has lifted from the main
> > board (or ANY board).
> > how do I fix a solder-pad that has lifted from the board?
> > Adam>
> >
> >
> > Adam
> >
> > Only one time (in my wild impetuous youth) have I tried to fix a
> pad
> > on a board. I had
> > some success using a hypodermic syringe (from a relative with
> > diabetes) and a carefully
> > placed drop of "super-glue" under then a wait of about two days. In
> > my case the traces
> > were OK but you should check carefully first.
> >
> > Remember: YMMV and no guarantees so, good luck. Hope this helps.
> > Bill
> >
>
>
5. Re: [ts2068] Solder pad problem
M. Emrah Oral · Thu, 10 Jan 2008 16:24
My hint is : be *VERY* careful IF you MUST use super glue. I messed up manyu things (not just PCBs) with super glue.
---------------------------------
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6. Re: [ts2068] Solder pad problem
Bill Dunlop · Thu, 10 Jan 2008 16:56
Yeah, I agree, the stuff likes skin better than almost anything else.
Solvent used by Dr.s is acetone in very small, frequent, amounts, don't ask how I found
out!
BTW my "pad" fix was on a simple pcb, anything more complex would have been way beyond
me.
Bill
--- "M. Emrah Oral" <[email]> wrote:
> My hint is : be *VERY* careful IF you MUST use super glue. I messed up manyu things
> (not just PCBs) with super glue.
>
>
> ---------------------------------
> Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
7. RE: Solder pad problem
Adam Trionfo · Thu, 10 Jan 2008 21:27
>>
For pads connected to other layers, it won't.
>>
Let me just clear something up here. The TS 2068 is a two-sided board only. Right?
Adam
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8. RE: Solder pad problem
Adam Trionfo · Thu, 10 Jan 2008 21:30
>>
for power connections you will need thicker wire than wirewrap.
>>
Yes, I know. I actually should ask about this. What is a good gauge to use?
Adam
_________________________________________________________________
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Video upgrades (composite, RGB, HDMI) · Repair & restoration