Wednesday, January 27, 2010
I've received quite a few emails on where to find the A14F rectifier diode, and my answer has always been: http://www.talonix.com/shop/item.aspx?itemid=8334
It turns out talonix.com doesn't have them and I do not know where to find them -- if anyone does, please let me know. (I obtained my A14F in a trade for a 2519N with an Apple 1 owner who has long since, sold his board, and I have lost contact with him, so I'm not sure of the source).
Posted by John at 11:30 PM
Wednesday, January 13, 2010
If you are interested in obtaining your own Apple 1 reproduction kit, you might want to check out willegal.net to see Mike's progress on the Apple 1 he is reproducing. Hopefully we'll all be able to purchase boards and kits soon!
I was also informed today that Cameron C. is starting a new community for Apple 1 enthusiasts : www.apple-1.org Cameron is still working on the site but stay tuned.
There are 2 guys working on wire wrapped Apple 1s.
I am working on short videos of my progress -- although my camera sucks, I'll see what I can make available (probably on youtube because of blogger's video size limit).
Posted by John at 6:36 PM
Mike Willegal had posted a question on applefritter.com awhile ago for someone to check/verify that pin 12 of the Address Decoder / 74154 was connected to ground. From the scans he was working with, he found that pin 12 was not grounded. I checked the board that came with the kit and could see visually, that pin 12 was grounded. At the time I assumed there was nothing wrong with the non-kit board I have, but I assumed wrong. Earlier this week I removed the DIP socket where the 74154 resides, because I wanted to check for solder-bridges under the DIP. I then placed multimeter leads (set to Ohms) from pin 12 to ground and verified that pin 12 is not connected to anything.
I resoldered a new DIP socket, and added a jumper from pin 12 to the ground side of the closest ceramic capacitor. Unfortunately, I am still picking up a 1+ volt signal on ground... more to come on this when I know more.
BTW, it appears at quick glance that the schematics omitted showing GND on each component.
Posted by John at 6:21 PM
Friday, January 1, 2010
For all of those who purchased an Obtronix board (not the kit) on ebay several years ago, there is a bug on this board. I can't say we all have the same board, but the board I have is missing a trace on D7 (74161) from pin 7 to pin 10. This bug was causing characters to repeat after a reset. I soldered a jumper wire across these pins, and the repeating chars stopped. This bug was found by Mike Willegal (willegal.net). I verified these pins were not connected by using a multimeter.
Posted by John at 11:10 AM