Replica 1 SE improvements

[vbriel]

I'm planning on standard green with white letters. I added the resistor values again to the board to make assembly easier.

Cheese - I know of some people who just use the Hyperterminal as their display! Just a thought.

[cheese1113]

I was actually referring to the color of the power led.

[vbriel]

Oh, duh, my bad. I was going to go with boring red since the Altair project uses red and I like using parts from other projects. I have a funny story about using parts from other projects. I designed the 4meg RAM card (RAM4GS) for Bill Garber a while back and when I did, I used a 74LS138 3-8 decoder instead of the 74LS139. They both work the same except the 139 only has 4 outputs instead of 8. I only needed the 4 but I had 138's laying around for the replica 1. To this day, Bill is still using the 138 on the boards because why change what works?

Back to the LED issue. Should we take a poll on the color LED to use?

Vince

[cheese1113]

LOL, great story!
I think a poll is an excellent idea.

[vbriel]

Well, the prototype boards came a day early so I dug right in. I've built everything except the voltage regulator section. Everything is working perfect. Usually there's one or two bugs somewhere but not so far. Next is to install the voltage regulator and try it with a wall wort power supply.

http://www.brielcomputers.com/files/SE1.JPG

http://www.brielcomputers.com/files/SE2.JPG

The USB adapter comes with the removable posts and I installed it on the prototype but I don't like it that way. I think it will be just fine mounted directly to the board.

Let me know what you guys think.

[cheese1113]

Looks awesome Vince!
If I were to get a tooth knocked out, and the tooth fairy gave me $159 I'd buy me this version.

[AutoMusic]

Vince,
Would you consider selling just the replica 1 SE pc board to owners of the original Replica 1 so we could upgrade? I would imagine most of the chips are the same. Maybe offer an upgrade kit with just the extra parts needed to convert a Replica 1 to SE? The SE looks great!

Steve Walker (AutoMusic)

[vbriel]

Interesting idea. I sure can. I'm working out the details with the board house now on board blanks. What you would need to convert is the new parts such as ATX connector, switch DC power connector, 7805 voltage regulator, resistors, 1mhz osc, switches, stuff like that. The keyboard adapter is different so you need the new version (atmega8 now instead of 8515). After I get rolling on production I'll work out an upgrade package.

Vince

[FunnymanSE30]

looks kind of wierd without the prototyping section

[vbriel]

I agree. Unfortunately it was dead space. I only personally know of 1 person who used it. What I'm going to do instead is offer a board that will give 3 Apple 1 slots and a 40 pin dip connector and cable that will go to a breadboard. This will make it easy for everybody to do solderless breadboard experiments.

The USB seems to work great, error free so far. ATX is perfect, the switch and LED are a nice feature.

Vince

[foresmac]

Here are my comments about the board:

I don't see any holes for wiring in external clear and reset switches.

Also, it looks like the USB port is far from the edge of the board, making it look difficult to have the ports flush with the case when you install it is one.

And maybe it'd be nice to have some extra +5V and GND holes for wiring in something like an LCD screen or something. I used holes for the AT connecter I left off to wire in my power LED.

Here's my total hack job wiring to maybe slightly illustrate:


I just butt the back of the baord up to the back of the case where I drilled some holes for the video and PS/2 connectors. I then drilled holes for a DC in jack and a power switch. It looks as though the USB connector would be too far in, but maybe the is just hte angle of the picture.

[cheese1113]

I agree with foresmac, I think there probably should be holes for the switches.

[vbriel]

I agree. I'm going to make a silkscreen adjustment and I don't want to be charged tooling for changing everything so I'll do a last prototype run with the additions for the clear screen contacts, reset contacts and 5V and GND.

I finally dug up a 7805 and tested the DC connector. 6V 300mA ran perfect and the 7805 never got even warm. This is the ideal voltage, less power draw to convert to 5V. I'll make the changes this week and get right in on a new board.

Vince

[foresmac]

Vince, I wonder if you were also able to enlarge the holes at the corners to work with standard PC mobo offsets, or if you know if something standard that works wit hte size holes that are on there.

I ended up using tiny wooden spools as stand-offs and #4 woodscrews to attach the board to them. It's not perfect, and the spools were drilled larger than the #4 screws, but it stays together fine as long as it is not turned upside-down.

[vbriel]

Yes, as a matter of fact, I'm using standoffs now on the SE, just installed them.