Commodore Amiga A500 Single Power - Build & Quick Review
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- čas přidán 9. 09. 2024
- Build and test of one of these:- github.com/Mas...
Massive thanks to Barry (sparxUK) for sending me this!
Github Project - github.com/Mas...
#commodore #amiga #retrocomputing
Github Project - github.com/MastaTabs/a500spwr
(@ 10:00 or so) Instead of trying to put them on in a weird angle like that, put a small blob of solder on both pads, then mount each component sticking straight up on the pad like a skyscraper. Once you have them, both on, join the tops with a small bodge wire. 😊
Also, try fitting a few 0.01 uF decoupling caps from ground to each of the +5, +12, and -12 rails right there on the top of the pins sticking through the PCB on the new board; that might help with the high-frequency switching noise. 😊
I am sure that wouldnt help here - it needs some filtering tailored to the specific frequencies. There are many many 100nF caps on the mobo, and right next to the power connections! From experience, this is the sort of thing that would benefit from the choke being in place - but we had to remove that to fit the new PSU PCB =/
I/P usually* denotes "Industrial" temperature rating
I'm quite a fan of RECOM tbh, very nice stuff! They do TO-220 7805 style replacements switchers as well
I often wondered if there was issues using switchers, you just confirmed my hunch...
I think I'd probably go the other way around and have 5V the primary supply, generating the +12 and -12. You'd expect their current draw to be minimal and their impact on audio and video out to be less severe. That said, hanging a spinning rust SCSI disc off the side might well suck more than a simple boost converter can supply to the 12V line, so I may be talking cobblers.
It is impressive, nevertheless. I think it will work fine on an A500 with an internal Gotek, maybe some RAM expansion, and a Compact Flash as a HDD, nothing to load the circuit much. But noise in the sound output is a showstopper for me, I may be wrong but AFAIK, -12V is also used by the opamps in the sound circuits of the A500.
Yes, you are correct - the opamp on these uses both +12v and -12v! I didnt hear any issues with sound though, it just seemed to be video!
Nice video and great job. Greetings from Steven from the Netherlands
Thank you very much!
The switch mode noise would be coming from that 12v psu you’re using to power the adaptor module with. Unfortunately most use a low switching frequency and that’s what causes the noise.
If you get a good quality 12v supply you probably won’t get any switching noise.
Regardless I’d probably just use the original Amiga power supply and just refurbish it
It probably is from the PSU used to power the module, I did (off camera) try a few different PSUs from different sources and still go noise =/ It's a problem with many of these new PSUs that are on eBay.
Great job soldering that PCB. I wouldn't even attempt it. Ha ha.
Thanks 👍
Howdy!😁
Hey again =D Thanks ever so much for everything you do for the channel!!!
@@GadgetUK164 More than welcome! I've learnt so much for you and the discord guys, it's only correct to 'pay it back'
It’s basically a poor solution for a problem that doesn’t exist when you consider the cost of a good aftermarket or refurbished original PSU.
I agree but from memory the one thing in it's defense is that it was designed _before_ new square din plugs became readily available so it was useful if you had a faulty plug or socket and were looking for a replacement that used widely available parts.