ACI Kit Arrived

Talk about your replica, what you have done and what you use it for

Re: ACI Kit Arrived

Postby tranter » Oct Wed 03, 2012 8:21 am

I don't know if this is related to any of the issues with the ACI but I thought I would mention it:

I normally power my Replica 1 with a "wall wart" but I did some testing with an ATX power supply. I noticed that when using an ATX supply the -12V line was quite noisy. I added a 100uF capacitor from -12V to ground using the prototype area and that filtered out the noise. Older versions of the Replica 1 had a 100uF cap from the -12V line to ground. the Third Edition omitted this for some reason (it's on the schematic but not the board).
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Re: ACI Kit Arrived

Postby collinp » Apr Wed 24, 2013 5:00 am

I finally got around to building my ACI kit. Contrary to other's experiences here it's actually working fairly well for me. At least as well as I assume the original worked. I definitely get bad loads from time to time but in general I can save to tape and load back from it.

Some observations :

I am running off a 9V wall wart. The card is strapped to wire -12V to ground as appropriate for the wall wart.

I was able to load SW from so the clock skew between the A1 and the R1 doesn't seem to be a deal breaker. I could believe that it messes with load reliability though.

The volume is critical. You must spend a lot of time searching for the sweet spot between too high and too low for each source you are using.

Even at the correct volume setting loading does not always work. I probably get errors about 10% of the time. I found the "Life" program to be useful. If I got the # prompt when I ran it but the program locked up then usually a reload without changing the volume would get it going.

I was able to load aiff files from a 2012 Retina MacBook Pro 15". The output volume was set to the 4th of the 5 tick points on the volume slider in System Preferences / Sound. Note that there appear to be two volume settings tracked : one when the headphone jack is occupied and another when it is empty. That messed me up a few times.

I had a much harder time loading files off my older 2010 MacBook Pro 15". I only got 1 successful load out of about 15 attempts across a range of volumes. If I attach amplified speakers to the older MacBook and crank them I can hear a bit of "digital noise" through the speakers. I don't hear that on my Retina machine. It doesn't seem crazy to think that some digital noise may mess up the ACI.

The most reliable source that I have tried is the Apple recommended Panasonic RQ2012. Though admittedly all my loads from this source were also saved to from the same R1 + ACI and that would eliminate clock skew as a factor. It seems like a volume of about 6 is working pretty well for me.

If you plug powered speakers into the ACI output jack while loading something on the input jack you can hear some of the audio load. There appears to be a volume level below which you suddenly cannot hear the leader or the data section. This is too low of a volume and there appears to be no need to try any volumes less than this.

I tried mono and stereo cables. I couldn't detect a difference. I'm running with mono cables now.

The cassette program doesn't exit when done. Hit ESC to exit.

BASIC and BASIC programs live in the 0xE000 memory range. Since the 0xE000 range is ROM and not RAM you can't load programs into it on the R1. Try Mastermind or Life which are assembly programs in the R1 RAM range.

The cassette program wants you to type all leading zeros. You must type 0280.0900R and not 280.900R.

- Collin
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