Amiga 600 schematics nearly put into Kicad

[squale]

@Stedy

@PurpleMelbourne


Great job guys, will follow it

[katarakt]

@PurpleMelbourne
Please don't forget the bootselector

[Mick]

Originally Posted by Stedy

Changing topic, I have a video bandpass filter working now. I'll try and shrink it down to a small plugin type board. Will play with the delay line if time allows over the next few weekends.

Nice one. If you want if you post/send the schematics I can try putting it into form and test it out for you?

I had a go at doing one myself but it didn't go too well, I think the DL portion is okay (180ns delay between 0-5.5mhz) but anything colour related looked wavy and there were horizontal scrolling lines slowly going up the screen. I don't know if it was noise or what, I used shielded inductors but I assumed the legs for mounting it were acting as antennas for noise and then just gave up, although it may be that I needed bigger ground connections. I tried using the force (and rf-tools.com ) but sometimes you just need expertise in electrical engineering I guess.




Aside from that I'm basically burned out. I have A600 2B done but I'd like a 2D board to do a replica of one of those. A1200 2B finished but I'm waiting on AOTL keyboards to be available to try that and that's been going on for 2 years. CD32 because what the hell about 75% finished just missing some routing and silkscreen (which looks like a PITA due to space). A600 in A1200 form factor finished aside from silkscreen but who knows if that will work. I just find Kicad way more fun than spending money and building boards unfortunately.

[PR77]

Originally Posted by PurpleMelbourne

I'd sure like a peek!
My secret plan has been to upgrade CPU to 030, Fast RAM and add a DSP56002.

I actually have some of these (and the DSP56001 variant) in PGA packages and also considering slapping one of these on my designs. What interface method are you planning to use?

[Cobe]

Originally Posted by squale

How about modifiying the A1200 motherboard to fit into the A600 case ?

[fpmpaolo]

Originally Posted by Mick

If anyone's interested I'm about 150 unrouted on this now (but still unsure about a few things mentioned above).

Hey man what do you mean with 150 unrouted. Are you selling one

[Mick]

Originally Posted by fpmpaolo

Hey man what do you mean with 150 unrouted. Are you selling one

It still only exists in a Kicad project, untested. I have routed it all now though. I'd have loved to have done an a1200 compatible expansion slot so you can use current accelerators but I'd need with that.

I've stripped an a600 rev 2d pcb down in the meantime, scanned it in at high res and done a near replica with thermal reliefs and a couple of fixes (C26 and U33pin 10 aren't connected to VCC like they should be). Cd32 finished too.

[Lemaru]

Originally Posted by Mick

I've stripped an a600 rev 2d pcb down in the meantime, scanned it in at high res and done a near replica with thermal reliefs and a couple of fixes (C26 and U33pin 10 aren't connected to VCC like they should be). Cd32 finished too.

Maybe interested in the 2d replica, as it would be a good base to add some tweaks and extra features too. Would like to keep it as near to original as possible though. Is that one going to get a release?

[trident]

hi is there a bom and were all the part should go on the a600 as i would love to do one for my system but dont want to get the wrong restistor on the board. is there link or download for the list of parts and were they go

[pixie]

Originally Posted by PurpleMelbourne

Already on it ;-)

That's quite a cool idea, that's what A600 should have been, AGA from the start!

[Mick]

Originally Posted by Lemaru

Maybe interested in the 2d replica, as it would be a good base to add some tweaks and extra features too. Would like to keep it as near to original as possible though. Is that one going to get a release?

Hopefully one day if I ever get around to testing it. I'm having to be a bit frugal financially since the government decided to nuke the economy with lock downs.

In the absence of Z221/Z222 replacement parts I've come to the conclusion that installing a CXA1645 or similar is easy enough in a stock board by just putting the capacitor/resistor they need in creative places if you don't need the RF modulator, if you do need the RF modulator then I'm not sure what impact it will have not having the audio buffer for mono out (CXA1145 exclusive feature).

Even a CD32 rev 4 should be easy enough to get working without Z221/Z222 if you use a Rohm BH7236 which retains the C-Sync pass-through.

[trident]

ok will answer my own question i found how to create the bom from schematic Editor
so am now happy on doing my first board when i order the pcb


is there anyone in the uk have the pcb as i only want 1 lol, not 5 from pcbway but if not then i will order 5 so there may be 3/4 left after i done mine

[seb132]

Originally Posted by Mick

Nice one. If you want if you post/send the schematics I can try putting it into form and test it out for you?

I had a go at doing one myself but it didn't go too well, I think the DL portion is okay (180ns delay between 0-5.5mhz) but anything colour related looked wavy and there were horizontal scrolling lines slowly going up the screen. I don't know if it was noise or what, I used shielded inductors but I assumed the legs for mounting it were acting as antennas for noise and then just gave up, although it may be that I needed bigger ground connections. I tried using the force (and rf-tools.com ) but sometimes you just need expertise in electrical engineering I guess.




Aside from that I'm basically burned out. I have A600 2B done but I'd like a 2D board to do a replica of one of those. A1200 2B finished but I'm waiting on AOTL keyboards to be available to try that and that's been going on for 2 years. CD32 because what the hell about 75% finished just missing some routing and silkscreen (which looks like a PITA due to space). A600 in A1200 form factor finished aside from silkscreen but who knows if that will work. I just find Kicad way more fun than spending money and building boards unfortunately.

A1200 in A600 form factor would be fun.

[kipper2k]

Originally Posted by trident

ok will answer my own question i found how to create the bom from schematic Editor
so am now happy on doing my first board when i order the pcb


is there anyone in the uk have the pcb as i only want 1 lol, not 5 from pcbway but if not then i will order 5 so there may be 3/4 left after i done mine

I would not order from PCBway, before you commit, check price of JLCPCB.com, they are far cheaper and their speed/quality is on par. For assembly you just need to create the BOM and CPL files. Kicad can generate these files for you and you will probably need to do a little editing. I wouldn't personally build the a600 board without all of the small caps/resistors being preassembled

[trident]

thanks for that i used jlcpcb a lot for my joystick pcb project so happy to order from them. used there editor (easyeda) a lot more then Kicad.
yes i had got the bom so pricing up the stuff i need and i have two old broken a600 as well for me been able to check if i done right. but thought i ask if any one in the uk had a spare board i would buy from them, but if no then ok i will order and if someone else like a pcb i may have spares lol any way thanks

[Mick]

I tried to order some A600 boards from PCBWay a bit back with a view to hopefully (once tested) selling some to help fund A1200 2B etc but for some reason they were adding £100-200 on top of the estimate, when I asked why they just said the system is not always accurate so I don't know what's going on there. I was still waiting for a Kipper2K keyboard from AOTL so never even did a A1200 for myself so that's not tested either.

I basically got carried away doing "other" stuff more recently which has helped me to practice copper fills better which means A600 is also improved, whereas before I just had a single copper slapped over the whole board which is a bit messy I guess.

I have to reiterate KiCad is more fun than most PS5 games these days, it's also even easier now you add a scan as background in KiCad 7, spending money on pcb's/parts and soldering not so much unfortunately. I feel like I'm letting people down but yeah not really completed anything unlike chucky whose brought about 10 boards to completion.

[SteveMoody]

I find PCBWay quite expensive on times, have a look on JLCPcb as well, I've used them for a few big boards and they all have been good so far.

I quite enjoy soldering but some of the surface mount parts on there could be a challange

[alenppc]

Originally Posted by SteveMoody

I find PCBWay quite expensive on times, have a look on JLCPcb as well, I've used them for a few big boards and they all have been good so far.

I quite enjoy soldering but some of the surface mount parts on there could be a challange

Not only that but the quality your receive from PCBWay is beyond dreadful. We got a lot of completely defective boards from them, they literally had shorted traces in random spots. Go with JLCPCB, at least you will get consistent quality.

[Mick]

I'm hoping to start doing something in the next month or two. It's just a case of overcoming the feeling of dread.

I'm thinking of doing MD2 first though as I've spent the most time on that and it should be easier and cheaper and I've actually made some improvements (while trying to keep it as original as possible):

General

> Modified some of the footprints for currently available parts (ie. d-subs, heatsink, power/reset buttons)
> Added solder jumpers for region and PAL/NTSC selection.
> Added an IC for the power on reset circuit instead of using the op amp as a comparator.
> I've implemented AVCC and VVCC properly, that is to say the VCC for audio and video components is fenced off behind an LC filter as was intended before what I presume was rampant cost cutting.

Video

> Added a capacitor to pin 9 of the encoder for CXA1645 support.
> Added two smaller bypass capacitors at each of the encoders VCC inputs as per datasheets.

Audio

> Added 75 ohm resistors to 32X inputs (missing on VA0 for some reason), from what I gather they're to reduce noise.
> Added footprints for a clean reference voltage near to the op amps instead of taking the noisy output from the RGB encoder.
> Removed the passive low pass filter on MCD output and added capacitors to mixing stage instead.

I think that's everything. I've been playing around with an old board and just replacing the op amps with something decent and giving them a clean VREF improves sound dramatically.

[pandy71]

Originally Posted by Mick

I think that's everything. I've been playing around with an old board and just replacing the op amps with something decent and giving them a clean VREF improves sound dramatically.

Go for very fast OPAMP - it should reduce distortions due Paula PWM volume control - typical OPAMP's are usually too slow to properly deal with 3.58MHz high level signals - personally i have plan to use buffers as I/V converter.