----- Original Message ----- From: "John Gardner" <[email protected]> To: <[email protected]> Sent: Wednesday, August 23, 2017 8:52 PM Subject: Re: [M100] Figtronix Main ROM adapter
> ...You could make a board where the chip is soldered on, and that > would fit in the original socket. The problem then is, that chip > would not be re-programmable very easily, because the combined > chip-on-adapter creates a non-standard pinout that a programmer > doesn't support... > > A pgming adapter sounds doable - And cheap... ----------- The price of an IC socket; same board... It's been quite a while; between Steve and myself we managed to lose some notes and it's not well documented, but one of the four jumper positions is to allow (re)programming; there's a default trace for 'normal' operation without jumpers that has to be cut. I'll have to revisit it one of these days... I thought about redoing it with larger holes that would take machined socket pins for a lower profile socket but it didn't seem worth while. And of course there's this version: http://www.club100.org/memfiles/index.php?action=downloadfile&filename=m100y2k.pdf&directory=Steve%20Adolph&; m ===================================> > > On 8/23/17, Brian White <[email protected]> wrote: >> The problem is that the new adapter is too tall for the available space, if >> it's plugged in to the original socket. >> >> The reason it's too tall is because of the plcc socket. Through-hole style >> plcc sockets are pretty tall. >> >> The way that adapter works, you lose the ability to plug the original rom >> back in, but but the new rom is removable and rewriteable without any >> further special adapters. You just pop the bare chip out and it pops into a >> standard reader, with an adapter too, but a standard one that comes with >> the reader just to adapte the physical form, notrearrange pins into a >> special pinout. >> >> There are lots of possible work-arounds, but they all have some kind of >> down-side just like desoldering the original socket is a down-side. >> >> You could make a board where the chip is soldered on, and that would fit in >> the original socket. >> >> The problem then is, that chip would not be re-programmable very easily, >> because the combined chip-on-adapter creates a non-standard pinout that a >> programmer doesn't support. >> >> You would have to make a "reverse adapter" to ever reprogram later, or get >> a test-clip that clips righ onto the chip on the board. >> >> I *think* it should bebpossible to make an adapter that plugs in to the >> original dip socket and still has a plcc socket itself, by using a surface >> mount plcc socket instead of a throu-hole one. There is a figtronix option >> rom board that uses that. I have made a few and they work. But the >> down-side in *that* case is that a low profile surface mount plcc socket >> can only be soldered with an oven or hot air and paste. It's MUCH simpler >> to solder the through-hole kind for the average hobbyist. I have managed >> it, and did it using a cheap $20 hot air gun instead of a $60-$500 "real" >> hot air soldering station, but it was tricky and finnicky and not reliably >> reproduceable. I also botched it several times and had to keep starting >> over. (heat it all up enough to come off, clean off all solder, and start >> over very carefully applying new paste and flux and trying lay the socket >> in exactly the right position...) >> >> No mmatter which way you turn, there is either one problem, or some other >> problem. >> >> Mike Stein has a board that uses a full dip chip, and can plug in to the >> original socket, but I don't think it can accomodate a socket to make the >> new, standard 27C256 removable for reprogramming and still all fit in the >> case. If it can, that would be the way to go. Otherwise it's just one of >> many equally good-with-a-problem options. >> >> Remember, this is all only for M100's that have the original non-standard >> pinout main rom. Some late M100's and all T102's don't have any problem and >> don't need any adapter. >> >> -- >> bkw >> >> On Aug 23, 2017 5:18 PM, "Gary Weber" <[email protected]> wrote: >> >>> Hello all, >>> >>> I have a question for anyone out there who has created a main ROM adapter >>> for their Model 100, using these parts and following these instructions: >>> http://tandy.wiki/FigTronix#Model_100_Main_ROM_27C256_PLCC_Adapter >>> >>> My question has to do with this statement: >>> "Unfortunately, using this adapter requires desoldering the original >>> socket from the motherboard. It IS possible to do this, without damaging >>> either the motherboard or even the old socket, with flux, solder wick, >>> and >>> patience." >>> >>> I'm a little confused as to why the original socket would have to be >>> de-soldered. Can't this adapter just be plugged into an empty CPU >>> socket? >>> Or is it the case that the M100 case can't close again because of >>> something >>> so high in that socket pressing against the keyboard circuit-board? >>> >>> Thanks for the info! >>> >>> >>> -- >>> Gary Weber >>> [email protected] >>> >>
