| ??? 05/20/05 16:40 Modified: 05/20/05 16:40 Read: times |
#93656 - Re: has happened Responding to: ???'s previous message |
Erik said:
This has happened to me too, but I would hold the likelyhood of that being the cause of the OPs problem at or below 1%. Of course, if the board was machine soldered. But I assumed that James had soldered his board by hands, with a solder iron. When I soldered SMD parts for the first time, I damaged terribly many of those 1206 ceramics! They all became much too hot. I didn't know that heat is an enemy of SMDs. But I learned it quickly: One of those ceramics showed a very very narrow break in the body, just where the ceramics touches the metal cap. So, they just break, when being heated up unsymmetrically. That's why soldering by hand can result in disaster, but mechanical reflow soldering will work. When that short was removed a 74HC14 which during the testing was driving DIRECTLY into the short to Vcc still worked. I experienced the same. These 74HCMOS-chips are nearly undestroyable! Kai |
| Topic | Author | Date |
| Temperature and 89C2051 | 01/01/70 00:00 | |
| Chip Grade? | 01/01/70 00:00 | |
| A bit vague | 01/01/70 00:00 | |
| oscillator? | 01/01/70 00:00 | |
| Built-in Pierce oscillators ARE reliable | 01/01/70 00:00 | |
| Freeze spray | 01/01/70 00:00 | |
| Overheated parts, too hot soldering? | 01/01/70 00:00 | |
| I have my doubts | 01/01/70 00:00 | |
| What about this? | 01/01/70 00:00 | |
| has happened | 01/01/70 00:00 | |
| Re: has happened | 01/01/70 00:00 | |
| Microwave oven | 01/01/70 00:00 | |
| not microwave, but toaster oven | 01/01/70 00:00 | |
| Thanks for replies | 01/01/70 00:00 | |
| How about this | 01/01/70 00:00 | |
| Wait a minute... | 01/01/70 00:00 | |
| Improvements | 01/01/70 00:00 | |
| resist | 01/01/70 00:00 | |
| Quartzes, etch resist | 01/01/70 00:00 | |
| Quartz Crystals | 01/01/70 00:00 | |
| Quartz crystals | 01/01/70 00:00 | |
no problem | 01/01/70 00:00 | |
| Maybe! | 01/01/70 00:00 | |
| Maybe! | 01/01/70 00:00 | |
| LED temperature rating? | 01/01/70 00:00 |