Video instructions and help with filling out and completing Where Form 8815 Affordable

Instructions and Help about Where Form 8815 Affordable

Music hello and welcome to this review of my leading edge 88 15 K I've been looking forward to showing you one of these for a long time as it uses the top of switch that's extremely rare and unusual the only other example I know of it is an NCR keyboard that ex mitt restored a long time ago but then this leading edge model showed up on desk Authority new old stock even and I offered to buy it that said after a lot of digging this board turned out to have a ton of history behind it leading-edge hardware products were an American company most well known in the community for the DC 2014 keyboard which is a common target for blue helps harvesting hopefully I'll get one of those someday to review as well as that's also a pretty interesting keyboard the 88 15 K appears to be the keyboard that came with a very first computer leading edge ever made the ironically named mobile em after Mitsubishi who supplied their parts this computer was released in late 1982 for $2,000 originally but it wasn't a huge success and what few pictures I could find of it which are on service manuals actually show it with the keyboard of its later brother the 1985 model D computer named after Daewoo who supplied their parts at that time and who contracted Alps to make the now well-known DC 2014 keyboard for it that said when leading edge couldn't supply the Mitsubishi dealers with their hardware they sued and leading-edge went bankrupt I was subsequently acquired by de woo as early as 1989 despite the huge success of the Model D computer that sent the 88 15 K itself are actually the model M keyboard as it should be known is much more of an enigma I can't find anything about the keyboard or even any picture of another one so far it appears to me unicorn the back label shows the FCC ID which is linked to an American company from Norcross jar-jar called key tech Inc of which the 88 15 K appears to be the only thing they filed FCC IDs for key tech was either dissolved or incorporated as early as 1983 and the FCC ID for the keyboard was transferred to leading edges own thx code shortly after so maybe key tech were acquired by them regardless key tech are also a dead end the only thing I have to go on are the switches which are a bit of a mystery themselves the switches on this leading edge appear to be almost identical to the ones on X MIT's NCR board but there are subtle differences for example the NCI is MX mount while the leading edge is not and this board has a small cutout in the bottom lip of the switches while the NCR doesn't they also have different manufacturers the NCR was made by Oak industries and Adi while the leading edge was made by key tech alone it seems Oak Industries was part of a mining and smelting conglomerate named Oak Mitsui and they were a major supplier of ultra-thin copper traces so they likely supplied just a PCB ad I on the other hand were a keyboard manufacturer so I think it's likely that they made the switches assembly and possibly the case as well the ADI switches appear to be clones of this key tech version or the other way around this one is from 1983 and although I don't know what year the NCR was built that one uses a 101 key layout and it's MX compatible so I'm pretty sure it's younger than the leading edge that's little to go on for a definitive conclusion I know but for the moment at least I'd say it's plausible that the key tech switches are the older of the two regardless these inductive switches are a very interesting design although the switch tops may not look very exotic if you take a look at the PCB you'll quickly realize there's some strange going on here the biggest giveaway are these circular holes in the PCB with circular tracers going around the edges which are typical for inductive switches it has these circular traces on both sides of the PCB except on one side is just the columns and on the other side it's just rows inductive switches are closely related to magnetic valve switches which by themselves are one of the most esoteric designs are now off but instead of using a magnet to regulate electron flow it uses only induction by way of this little ferrite bead riveted to the slider here ferrite is a type of composite material with iron filings which means it can be easily magnetized it's often found on cables of all sorts of electronic devices including keyboards and acts as a low pass frequency filter to prevent electromagnetic interference to and from other devices however it can also be used to carry a magnetic field so to speak as the keyboard scans for key presses it sends a pulse it down the column traces which as we saw earlier are shaped like a loop recall that electricity going around in a loop generates a magnetic field when the user presses a key down far enough the ferrite bead comes down through the hole and at some point the column tracers will be inductively coupled to the road tracers on the other side through the magnetization of the ferrite bead all the Tassili then on the row side is listen for a current now because the current induced into the rows is very weak at first has to be amplified because otherwise is simply too small to work with so every row has this little toroidal core which is basically a very simple transformer with one loop going in and about twenty coming out so it implies Dad going voltage

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