This has to be one of the greatest blogs out there. Please, keep it up. And thanks for all your awesome posts!

Cheers!

Amazing ! Any good online seller of this T-40B shipping worldwide ?

@ qdx

good online seller is mouser.com

Just in case any one is interest the T-40B has been retired and replaced by the RT-50 now.

http://www.sunpower-uk.com/products/50W-Triple-Output-AC-DC-Enclosed-Power-Supply/RT-50-Series/default.htm

I have just completed this mod with the above PSU.

@Rave

Hi,

Which model RT-50 did you use? Can it also be use on the A1200 model?

Thanks

Howard

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Why use a power supply that is weaker than a A500 psu originally was.. +5v was 4.5amp on A500psu and +5v is what is important. You are in effect making it as weak as A600/1200 psu. While it will work for most machines, heavily expanded ones may have problems.

Another thing to consider is many of these caged psu’s were designed to be in a fanned enclosure,and although the 500 might only push the specs,this should be considered. The data sheet should indicate if a fan is needed.

Mean well makes some terrible psu’s(not all). Many have high ripple and some come with poor quality caps. As usual check the datasheet.

I hope this doesn’t come off as negative,i just want to point out the facts to users.

Ma saresti in grado di farne uno per un A1200 che monta PPC e Bvision?

Esiste qualche dettaglio in più di questo progetto?

A bit late to the party… I have RT-50B that I’m trying to use in a project with one loose A500 motherboard. It works and powers it up fine, but I have slight waves going across my monitor that I don’t have when using normal Amiga PSU, aka noise. Is it possible to get rid of it, or that’s just how it goes when using these kinds of PSUs?

Excellent job with the pictures. One question though, what did you do with the large black cable (in IMG_1402 & 1406?) I.e, the one which comes out together with the five connectors on the left/DC-side (and was soldered onto the other side on the original PSU)? I can’t see where it goes, and it’s not hooked up to any of the terminals on the new PSU, AFAIKT. (It disappears in the rightmost corner of pic IMG_1402 – http://www.nightfallcrew.com/wp-content/gallery/commodore-amiga-500-replacement-power-supply/thumbs/thumbs_IMG_1402.jpg

Thanks again for documenting this. Guessing a lot of Amiga owners are going to replace their ailing with a new Meanwell PSU.

Thanks for clarifying that @Dave. I guess I’ll just cut off (& terminate) that cable then. I was thinking of hooking it up to ground (based on suggestions from others), but not sure if there’s any real benefit in this.

btw-it’s funny how all the pics and the videos (that I’ve seen so far) omit this little information as that cable is quite prominent. :)

Cheers,

Martin

Just for info, I’d recommend the MeanWell RPT-75B because it has superior specs (6A on the 5V rail), and fits the case good enough. You will however have to make your own mounting plate to accommodate for the new hole pattern of the PSU. I will post such an adapter on GrabCAD for those who have a 3D printer nearby. So far I have converted 3 of mine PSUs, and they can power any hungry accelerator, disk or memory expansion without breaking a sweat… :-)
Link: https://www2.mouser.com/ProductDetail/MEAN-WELL/RPT-75B?qs=%2fha2pyFaduj89TKwmmRVV00hY%2fzVMNOqNSgmhXyUhX0%3d

Mean Wells RT-50B is plenty powerful enough with its max 5A rating on 5V line. Keep in mind it requires minimum 0.2A load on +12V for stable operation, so a power resistor (39 Ohm, 5-10W) should hjelp. You can do the same for the -12V with 82 Ohm 3W if you want. My A500 psu was fine, so I just recapped it.

Anyone know if the RPT-75B also has the 0.2A minimum requirement on the +12V line?
(Yes, I still haven’t mounted my RT-50B yet – way too many projects in the air)

Contrary to other claims about being a drop-in replacement, the RT-50B also does not fit in the case via any mounting holes so either drilling or making a simple adapter plate is required. Its size was the main reason I got it (and the reduced hassle of having to modify the chassis, which turned out one still had to do!) :)

Well, to answer my own question :p it appears this is indeed the case according to the datasheet for the RPT-75B – 0.2A minimum on the +12V line & 0.1A on -12V (& 0.6A on 5V)

So on paper, it does not seem to be much of a difference (although 0.6A on 5V might actually be a drawback)

In this regard the RT-65B is probably better, with min req of 0.5A on the 5V line, 0.2A on 12V (same for all) and 0A on -12V.

Sorry for the extra noise. But if anyone has encountered any practical differences/benefits it would be useful to know.

its very nice and helpful blog about electronic thanks for sharing

@Mech
Yep! I am late here, but this may be of interest for future readers.
Thanks @xAD/nIGHTFALL for the article, and thanks @Mech for the technical insight.

My original A500 PSU (“Power supply A 500 P/NO 312503-03″) just failed and I am about to follow this mod.
@Mech, to answer your concerns:

1) About power: my original A500 PSU is +5V 2.5A, +12V 1A and -12V 0.1A. So this T-40B matches with some security margin (I have no other mods but a Gotek).
2) About cooling: I found the datasheet (Google: “Mean Well t-40b pdf”) and it states “cooling by free air convection”. So it should be fine… provided the vents on the Commodore box allow enough air flow.

About the cooling, feedback from the people who did the mod a few years ago would be nice.