- ADM-3A Wonky Until Warm - 6 Updates
- Devices to fool the Power Meter - 1 Update
- Panasonic microwave, blown inverter board transformer - 1 Update
| Tom Lake <tomlake07@gmail.com>: Jun 19 12:02AM -0700 I have an ADM-3A dumb terminal and when I first turn it on the display is squashed and the top line is mangled. After five minutes or so the display looks OK but is a little jumpy. After a few more minutes, the display is rock-solid and stays that way until the next time I turn it on cold. If I turn it off back on, the display is still fine as long as I don't let the ADM cool off first. Does anyone know what the problem might be? What to look for? |
| Andy Burns <usenet@andyburns.uk>: Jun 19 08:18AM +0100 Tom Lake wrote: > minutes, the display is rock-solid and stays that way until the next > time I turn it on cold. If I turn it off back on, the display is > still fine as long as I don't let the ADM cool off first. Sounds like the sort of issue you could track down by a can of freezer spray (or inverted can of air duster) |
| Sjouke Burry <burrynulnulfour@ppllaanneett.nnll>: Jun 19 10:04AM +0200 On 19.06.20 9:02, Tom Lake wrote: > I have an ADM-3A dumb terminal and when I first turn it on the display is squashed and the top line is mangled. After five minutes or so the display looks OK but is a little jumpy. After a few more minutes, the display is rock-solid and stays that way until the next time I turn it on cold. If I turn it off back on, the display is still fine as long as I don't let the ADM cool off first. Does anyone know what the problem might be? What to look for? Check for bulging caps. they are failing, and work best at a bit higher temperature. |
| mjb@signal11.invalid (Mike): Jun 19 11:18AM +0100 In article <faf31817-c4a8-45c6-9ee1-be492f434cf4o@googlegroups.com>, > it off back on, the display is still fine as long as I don't let the ADM c= >ool off first. Does anyone know what the problem might be? What to look for= >? A can of freeze-it spray, a plastic/otherwise completely insulated poking device, and a very old soldered joint/failed component in the vertical deflection section. Including inductors that may not quite be making contact between the enamelled copper wire and its pins, capacitors/resistors with hairline cracks in. Once it's warmed up and "just about" working, cautiously poke, tap, or zap with cold-spray and see if it fails. Any sight/sound of arcing/sparking when it goes from working to not? If so, observe it in low light conditions and keep your eyes open. Better still, aim a camera at the board to see where it sparked, in case you miss it. -- --------------------------------------+------------------------------------ Mike Brown: mjb[-at-]signal11.org.uk | http://www.signal11.org.uk |
| Ralph Mowery <rmowery28146@earthlink.net>: Jun 19 10:19AM -0400 In article <5eec71a2$0$1239$e4fe514c@textnews.kpn.nl>, burrynulnulfour@ppllaanneett.nnll says... > On 19.06.20 9:02, Tom Lake wrote: > > I have an ADM-3A dumb terminal and when I first turn it on the display is squashed and the top line is mangled. After five minutes or so the display looks OK but is a little jumpy. After a few more minutes, the display is rock-solid and stays that way until the next time I turn it on cold. If I turn it off back on, the display is still fine as long as I don't let the ADM cool off first. Does anyone know what the problem might be? What to look for? > Check for bulging caps. they are failing, and work best at a bit higher > temperature. I would also check for bad capacitors. Instead of the freeze spray, try heat. I have a hot air rework station and the heat wand has a very small nozzle where I can heat a small portion at a time. The heated capacitors usually make the problem go away very quickly when the device is first turned on. |
| Rob <nomail@example.com>: Jun 19 04:38PM > small nozzle where I can heat a small portion at a time. > The heated capacitors usually make the problem go away very quickly when > the device is first turned on. In a device of that age, start by replacing all larger caps (physical size of 12mm/.5" in diameter and larger) and re-solder all largish pins in the circuit boards (inductors, transformers, connectors). When there still is a problem after that you can use heat/cold to hunt for a smaller failed component. |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jun 18 12:20PM -0700 Power utilities are not unsophisticated, at least around here. We installed mini-splits in early January covering two floors of a 3-story, 5,000 s.f. center-hall colonial build in 1890, and substantially enlarged in 1928. In mid-May, the utility (PECO) sent a gentleman around to check both our electric and our gas meters. Our electric bills had dropped by a few percent, but still dropped, and our gas consumption had dropped by 2/3. The gentleman took one look at the outside compressors, and made an 'all-is-well' notation. It is now mid-June, has been quite hot, but our electric bill is now the one down by 2/3 from last year, with our gas being nearly the same as we still cook, use hot water and dry clothes. Moral of the story - if your established (11 years for us) use pattern changes suddenly and significantly, the Utility *will* notice. Peter Wieck Melrose Park, PA |
| Jeff Liebermann <jeffl@cruzio.com>: Jun 18 10:10AM -0700 On Thu, 18 Jun 2020 23:22:57 +1000, Clifford Heath >So presence of vapor is a good indicator of the outside temperature of >your food, even before the water starts to boil. >CH Yep, but there's a little more to it. The 1978 Panasonic patent agrees that it's the surface temperature that's important. "Apparatus for controlling heating time utilizing humidity sensing" <https://patents.google.com/patent/US4097707> See "Description" section: ...it has been known to sense the temperature of the food or degree of heating by measuring the change of humidity which takes place as the food is heated. For example, in most foods, water included therein abruptly evaporates when the temperature of the food reaches 100° C and a large amount of water vapor appears in the oven. By detecting such change of humidity by a humidity sensor, the time at which the humidity abruptly changes can be related to the time at which the food has reached 100° C. Further down the "Description" section, the patent explains how the cooking time is extrapolated from the 100° C point and the target temperature. Apparently, the humidity sensor is only interested in a single point, where the air abruptly transitions from low humidity to high humidity at 100° C. Everything else is done by temperature curve extrapolation. Crude, but effective. -- 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 |
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