All the parts on the list I used and they worked fine. Some of the later parts of the numbers have to do with the speed of the parts, package type and temp range. So long as the speed is better than that specified you should be fine. Temperature range is not really relevant in this application. The only issue is that some of the memory and flash parts might be in reverse format where the pins are mirrored to the normal part, this made laying out boards much easier in the day. This projects needs the normal format TSOP package.
I would suggest sanding along the length of the board it could start to delaminate if you tried to go any other way, the OSHPark boards are not of very high quality. You will find once you have passed the thick part and entered the holes it will grind away much quicker just keep checking to make sure you do not pass the guidelines. The first one I did I nearly overshot LOL. Programming in the Model T could cause all sorts of problems the socket on the board is live, not just with +5V, there are quite a few active signal lines that go to the socket. IF the REX board has a short you may end up shorting out the +5V lines themselves which could damage the power supply on the model T. The JTAG lines used to program the Xilinx also appear on the edge of the board which means they could end up driving signal lines on the board and over stressing components when programming. If you have any sort of mishap while programming the board it could translate into a damaged Model T. The Model Ts are pretty well beyond their expected life and in the failure part of the life cycle so any additional stress might just push it over the edge. You will most likely lose all the RAM contents so make sure you have a backup of anything important. If you do go this route you might want to hold the model T in reset so it is not actively running, the +5V will still be present. Rig it so the reset button is pressed & held in while you program. Personally using the model T would be a none starter for me. A cheap alternative might be https://www.jameco.com/z/34020-Solarbotics-5V-Breadboard-Voltage-Regulator- Kit-Unassembled-_2115750.html. This is a +5V power board that does need assembly but think of it as practice for the REX board. You could then rig up a protoboard with the REX and this supply, then play and experiment without worrying about the Model T. Might reduce the stress levels all around :) You also have a +5V supply for the next project that comes along and piques your interest. Before applying power run a quick continuity check on the +5V make sure there a no shorts. Also inspect all the pins and around the capacitor to make sure no solder has shorted out any pins. There are no solder balls or streaks anywhere. I usually ³wash² all my boards with water/alcohol mix and an old toothbrush after assembly and before I very carefully inspect them. You can dry them with a paper towel. If in doubt post the concern/question there are some very knowledgeable folks on this site who can probably address just about all issues related to the Model T. On 21/9/17, 5:03 PM, "M100 on behalf of Jim Anderson" <m100-boun...@lists.bitchin100.com on behalf of jim.ander...@kpu.ca> wrote: >> -----Original Message----- >> >> All the items are available on eBay at much lower prices. >> >> I bought enough parts for 10 Rex units and 5 Quads in May and the total >> cost for the parts was around USD $70. Here are the links (some of the >> prices have increased since I bought), hope you find them useful: > >The link to the Toshiba SRAM was VERY useful, thank you! Part of the >problem I have trying to source this stuff (on ebay or even on other >electronics retailers' sites) without having a BOM in-hand to refer to is >that I don't know which parts are equivalent. The SRAM is *mostly* the >same part number but I have no idea whether the differences in the last >four letters mean there is something different about it that will make it >unsuitable for use in QUAD, you know? > >I didn't end up ordering the Xilinx chips from ebay though because the >per-chip cost after shipping and currency conversion was only slightly >lower than Digikey's price... > >> Some of the items originate from China however they arrived well before >> the boards from OSHpark which took about 14days for my order, however >> YMMV. At least for the US there were no import charges. > >Yeah, that's unlikely for me - most of the stuff I get from China >(especially anything with free shipping) is usually four weeks or more. > >> I would not recommend programming the boards in your beloved Model T so >> many things can go wrong. Just tack on power wires and use a bench >> supply set to 5V. > >I think the suggestion of putting it in the model T to power it was for >those of us who don't have a bench supply. :( What sort of things might >go wrong? > >> The other issue was grinding down the edges of the REX board, watch for >> the through hole plating it has a tendency to fold into the hole and can >> cause problems. I cleaned that out with a small needle file. if you > >Good tip - I wonder if it would work better sanding in a perpendicular >motion rather than along the length of the board edge? I was also >wondering if this could be improved upon (for those who have one) by use >of a finer-grit paper in an orbital pad sander? > >> As they say Slow is Pro! Above all have fun building them, nothing like >> seeing your efforts come alive on the Model T. > >Keeping my fingers crossed. :) > > > > > > > > jim
