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| Cursitor Doom <curd@notformail.com>: Feb 09 11:23AM Hi all, Anyone got any tips on how to avoid the unpleasant situation where you try to de-solder a part on an elderly board and end up removing more than just component leads? Most of the stuff I work on is at *least* 25 years old and things start to get fragile. thanks |
| John-Del <ohger1s@aol.com>: Feb 09 04:14AM -0800 On Tuesday, February 9, 2016 at 6:26:21 AM UTC-5, Cursitor Doom wrote: > just component leads? Most of the stuff I work on is at *least* 25 years > old and things start to get fragile. > thanks Preheat the board before desoldering and apply some liquid flux. Make sure to use *enough* heat as too low is just as bad as too much. You want to reduce the time it takes to finish the process more than anything. |
| Adrian Caspersz <email@here.invalid>: Feb 09 12:14PM On 09/02/16 11:23, Cursitor Doom wrote: > try to de-solder a part on an elderly board and end up removing more than > just component leads? Most of the stuff I work on is at *least* 25 years > old and things start to get fragile. Tip on a more powerful iron? -- Adrian C |
| Chuck <chuck@mydeja.net>: Feb 09 07:48AM -0600 On Tue, 9 Feb 2016 12:14:32 +0000, Adrian Caspersz >> just component leads? Most of the stuff I work on is at *least* 25 years >> old and things start to get fragile. >Tip on a more powerful iron? Been using this one professionally for years. http://www.mcmelectronics.com/product/TENMA-21-147-/21-147 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
| Geo <nhhu-o3hu@dea.spamcon.org>: Feb 09 03:21PM On Tue, 9 Feb 2016 11:23:24 -0000 (UTC), Cursitor Doom >try to de-solder a part on an elderly board and end up removing more than >just component leads? Most of the stuff I work on is at *least* 25 years >old and things start to get fragile. I used to service scopes and DVMs and other testgear in the service department of the manufacturer. At the time they did not use surface mount so any duff IC, transistor, diode etc had all its pins cut on the top of the board then each pin removed individually (using spring loaded solder sucker or vacuum device depending if in field or not). |
| N_Cook <diverse@tcp.co.uk>: Feb 09 03:24PM On 09/02/2016 11:23, Cursitor Doom wrote: > just component leads? Most of the stuff I work on is at *least* 25 years > old and things start to get fragile. > thanks At least you don't need fume extraction as no throat-grabbing noxious PbF stuff. Go around each blob with fresh multicore solder, heating just enough to introduce some new solder, but no great depth. Then long nose pliers on the other side of the board and as much tug as you can give, while reheating the solder. Repeat for each pad. |
| N_Cook <diverse@tcp.co.uk>: Feb 09 03:30PM On 09/02/2016 15:24, N_Cook wrote: > introduce some new solder, but no great depth. > Then long nose pliers on the other side of the board and as much tug as > you can give, while reheating the solder. Repeat for each pad. Then when finished, a needlepoint (steel ,not S/S needle set in a pencil or something as a handle) set point in the hole , heating the needle with soldering iron while pushing through pcb and waggling , to give good clean h |
| Cydrome Leader <presence@MUNGEpanix.com>: Feb 09 04:21PM > try to de-solder a part on an elderly board and end up removing more than > just component leads? Most of the stuff I work on is at *least* 25 years > old and things start to get fragile. Add fresh solder and liquid flux, then solder suck or use braid. old solder has oxides and crap on it and is a poor heat conductor, so you you can end up burning the pads off the board if you fight with it too long. Cutting Leads off the part can help too if they were wedged into the holes. |
| stratus46@yahoo.com: Feb 08 08:06PM -0800 On Wednesday, February 3, 2016 at 10:14:36 PM UTC-8, David Farber wrote: > -- > David Farber > Los Osos, CA CAPS |
| Jeff Liebermann <jeffl@cruzio.com>: Feb 08 08:24PM -0800 On Wed, 3 Feb 2016 22:14:12 -0800, "David Farber" >inspected the caps and they don't look or test bad. The CPU and motherboard >temps are normal. Has anyone experienced this type of problem before? >Thanks for your replies. Your description sounds exactly like the usual bulging capacitor problem on the motherboard or in the power supply. You said that you checked (tested?) the motherboard caps, but did you check the power supply caps? The hardware monitor is more commonly called the "power good" line on an ATX power supply. It's suppose to be near +5V so your +1.5v indicates that the power supply is not happy. <https://en.wikipedia.org/wiki/Power_good_signal> Incidentally, what's happening is that when cold, the ESR (equivalent series resistance) of the electrolytic capacitors is rather high, resulting in lots of ripple, lousy regulation, bad breath, circuit malfunction, and other undesirable things. However, as the capacitor gets warmed up by the ripple current or nearby hot components, the ESR goes down allowing the sick capacitor to act like a good capacitor. The computah will probably work reasonably well, as long as it stays warm, but will revert to simulating a stubborn mule when it cools down. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| Adrian Caspersz <email@here.invalid>: Feb 09 10:17AM On 09/02/16 04:24, Jeff Liebermann wrote: > good" line on an ATX power supply. It's suppose to be near +5V so > your +1.5v indicates that the power supply is not happy. > <https://en.wikipedia.org/wiki/Power_good_signal> Agree with the caps diagnosis, I'd also follow the +5V standby supply into the board with a meter while changing power state. However, the +1.5V line, is that the CPU voltage voltage? 1.298V looks in the ballpark for the CPU in that unit. -- Adrian C |
| William Cox <bill.tsec@gmail.com>: Feb 08 03:33PM -0800 Hi: Am trying to fix a Tek 2215A with the delayed sweep not functioning properly. I am able to see both A and B sweeps but am unable to use the B Time delay position. Anyone have an idea? Thanks |
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