Månadsarkiv: oktober 2024

Amiga 4000D front LEDs

Publicerat av
Here is my black Amiga 4000D with a green power LED

I bought a replica Amiga 4000D case off of Amibay earlier this year. One of the joys of building and buying clones and replica hardware is the challenge of finding parts you need. In this case, I needed a front for the A4000D. Thankfully there was 3D model you could download and 3D print that solved the problem, but it did not came with LEDs or the keylock so here came another challenge: find the correct parts for the LED, how to mount them and where to find the keylock.

Amiga 4000D LEDs

Amiga 4000D front panel LED

So the LEDs are standard square, flat 5v LEDs. These can be found in most electronic shops, here is a link to the green ones I bought. I think green looks fine, there was yellow and orange also and probably blue if you look around. I am not that fond of blue leds so green was it.

A4000D uses a two pin Molex connector and a flat LED

The LEDs are mounted to two terminal Molex connector (2.54mm). The Molex connector slips into the opening over the cable sleeves. If I remember correctly this is actually how they are setup on a genuine A4000D. On the picture above you can see the long pins of the LED sticking out through the back of the Molex connector, I cut these off and bent them over the Molex connector afterwards.

There are magnets on the back of the A4000D front that holds it to the chassi.

Here you can see the 2 pin Molex connector placed into the holes for the LED. On an older A4000D I had (a genuine one) I put a dab of hot glue on them to hold them in place, perhaps I will do it on this A4000D replica too in the future, but for the moment they stay fit on the A4000D front with no problem. You can also see the cables, they are soldered to three pin 2.54mm connectors. One pin is left out.

Cables are inserted to the A4000D motherboard

At first the LEDs did not light up, so I just switched positions on the cables and then they worked as they should. If you look at the A4000D motherboard circuit to the pinouts, you can see that the middle pin is unique, but the two outher pins are the same (hooked up together). So if you have the correct polarity you can flip them around and they should work.

Amiga 4000D keylock

Amiga 4000D front with keylock

The Mouser part number for the keylock is, 612-KO132A1501 – here is the page for it on Mouser. If I remember correctly the keylock does not disable the A4000D from working, it just disables the keyboard. And to be totally honest, a keylock in this day and age is kind of pointless, however the A4000D front would not look correct without one, so I ”had” to get one. I just soldered two wires to the terminals of the keylock and hooked it up to the motherboard.

Got my ZZ9000AX Amiga sound card running

Publicerat av
The ZZ9000AX Amiga sound card for the ZZ9000 graphics card

There is a sound card for the ZZ9000 Amiga graphics card called the ZZ9000AX. It is a small soundcard that is attached directly to the graphics card.

I had some problems with the ZZ9000AX

Keep in mind that I am running the card on an unofficial Amiga motherboard so that might be the case (A4000TX) and not the fault of the soundcard.

I got one of the soundcards last year but had massive problems getting it running well. The ZZ9000AX seemed to be picking up noise off the buss and many times had a disturbingly loud background buzz that never stopped. Paula sound is passed through the ZZ9000AX and when Paula output was passed through the ZZ9000AX it just sounded horrible. Sometimes distorted, sometimes just totally wrong, so far from the regular crystal clear Amiga sound output I was used to.

I was sent a replacement card from MNT but it did not fix the problems, just introduced different sounding problems. I am not blaming MNT for these problems – as I was running it in my A4000TX which is a non standard Amiga model (with no public schematics), there might be some kind of difference between an A4000D CR and an A4000TX that introduces these problems into the audio output. Without schematics it is not possible to go further investigating the problem. I am going to test my card on my other Zorro machines in the future to find out if it is the fault of the A4000TX or not (will update this text). But the card was sadly unusable for me in my A4000TX.

Finding a solution

ZZ9000AX with external to internal cable

Playing around with the card I noticed that if I removed the three wire cable that connected Paula audio output into the ZZ9000AX (you can see it attached to the card above) the card was beautifully silent, no bus noise, no irritating static and no weird noises. Playing MP3s worked fine. So I got an idea to remove the three cable wire and route the output from the ZZ9000AX into the Paula input header so the output of the soundcard was mixed into the sound jack of the A4000TX.

Cable in detail, it is just a simple cable, nothing special to be honest

I created this little cable just to prove if it could work. I will make a nicer looking cable in the future. The A4000D and the A4000TX (that is based on the A4000D CR) has a audio in input on the motherboard, likely for CD-ROM input or for AV purposes.

It is connected to line in on the A4000TX motherboard so it gets mixed into the output for the sound socket.

You can see the cable connected to the audio input header on the image above. It is a messy setup, but the system is in a state of work in progress at the moment.

The cable is just a nasty quick hack, I will do something better here in the future

Here is the backside of the A4000TX and how I route the cables to the internal audio input. No doubt I will create a more neat solution in the future, but for now this will do.

Does the fix work?

Yes it does, I have configured AmigaAMP to use the MHI drivers for MP3 playback. Both MHI and AHI works fine. There is no bus noise and no ringing noises in the background. The sound output is dead silent when Paula is not creating sound or an MP3 is not playing, just as I expect it to be. And best of all, playing modules in an module player sounds crystal clear. Playing MP3s on my Amiga sounds just as they do on my PC now!