Hi
I’m in the middle of the daunting task of building an Apple 1 replica from scratch, but I have run into some questions along the way and I can't find the answers anywhere. And I was hoping some of you could help me:)
1: My first question is about the ceramic disc capacitors. I have found some I think should work but I'm not entirely sure. Will these one’s work? I’m mostly concerned about the 0.1 uF one.
0.001uF:
https://www.mouser.dk/ProductDetail/72-VY2102M29Y5US63V7
0.01uF:
0.1uF:
https://www.mouser.dk/ProductDetail/594-S104Z93Z5VL83L0R
2: My second question is about the video potentiometer. Are there any requirements for the power rating? Would this one work?
https://www.mouser.dk/ProductDetail/72-T7RYA-100
3: I live in a PAL region specifically Denmark but the Apple 1 outputs NTSC video i’m guessing. Is there a mod to change it to PAL. I know that on some Commodore computers you can change the crystal to a different value to change it from NTSC to PAL. Will something like that work on the Apple 1 or will it screw the whole clock circuitry up?
5: I’m having a hard time finding a diode to substitute the MR500/A14F since I can’t find either of them anywhere. As far as I can see a 1N5400 should fit, is that right?
https://www.mouser.dk/ProductDetail/863-1N5400G
6: My last question is about the power supply. I live in Denmark which uses 240V but the transformers listed in the BOM I follow are for 120V i’m guessing. Does anyone know what transformers I need to use and what voltages should the transformers output into the computer?
Thank you so much in advance. I hope there aren't any stupid questions :)
Best regards William
... can be answered if you had my "Tips & Tricks" pdf for the builders of my kits.
The kits are long sold out / gone but I still have the pdf to give away for free ;-)
Send me a PM with your email and I will send you the pdf.
- Uncle Bernie
... there is NO way to turn the Apple-1 from 60 Hz field rate to 50 Hz field rate.
(Well I could probably do it but it's not worth the effort (pay me $1 Million and I will waste my time on it, you see, I'm very humble with my hourly rates on custom design work for third parties)
Almost all vintage B&W monitors have a "VHOLD" adjustment knob with enough range to dial them to 60 Hz field rate.
And most more modern LCD based TV can "understand" 60 Hz frame rate. These chip sets were designed for worldwide use.
What you might need to add is my "video fix" and the link is in the "Tips & Tricks" pdf.
- Uncle Bernie
Hi William.
For power supply you can use:
HAMMOND 186D10 for the 10V (10V - No Center Taping needed)
HAMMOND 186D28 for the 28V (14V + 14V - Center Tapping)
They're quite largely available from most retailers (i.e. Mouser).
NTSC and PAL standards refers to color encoding, and Apple-1 is just Black and White, so this question simply does not apply here. :-)
About the 50-60Hz: this won't be an issue: any monitor is potentially perfectly able to lock on the '60Hz' video output.
However, you could experience blank/malformed screen depending on how finicky your monitor is regarding the not-so-well-formed Apple-1 video signal.
To partially fix it, as already mentioned, you can apply a very easy and non-invasive mod to the PCB.
Here's the schematic:
https://www.applefritter.com/files/2021/12/08/A1_VIDEO_FIX.pdf
Good luck with your build!
Regards,
Claudio - P-LAB
Thank you so much Claudio
Mouser-Parts:
Heatsink: 567-680-125A
Edge Connector: 587-305-044-521-201
Trimpot: 652-3329H-1-101LF
Mica: 598-CD15ED470JO3F
The Sprague 39D caps are still available at Mouser.
Some parts are out at the moment, but they will come back in stock...
I use 2x14V and a 8V transformers from Reichelt. If you have a good LM323K 8V AC is enough for about 2 Amps on the 5V line. I measured 8V in the valleys at normal Apple 1 usage with 8k RAM and ACI (about 1,5A). 3V above 5V is more than enough for the regulator (it needs >2V dropout). With my stepper/analyzer card with 6xTIL displays and about 2 amps load at 5V it drops to 7V in the valleys. Thats OK, but the limit with 8V transformer. But the good thing with 8V transformer is that the heatsink doesnt get so hot !
Christian
I have dozens of leftover sinterglass diodes, as I had bought a pack of 50 on eBay for my build. Not sure if it's worth shipping them across the ocean, but I have them.
IMG_1305.jpg
... I have hundreds of them left, the same ones which were used in my kits. I had to buy all of them which the seller had in stock, or get none at all.
If you live in Germany, send me a PM to learn more on how you could get them cheap ...
- Uncle Bernie