PicoPSU: is it really enough for the CT60?

[mikro]

Rodolphe Czuba says on his website:

CT63 needs a voltage of 3.3V and 8 Amperes at least for the 060, the SDRAM, the 060 BUS port, the logic and the buffers

Yet every PicoPSU I've seen on eBay offers something like max load on 3.3V of 6A, peak load of 8A with strong recommendation not to exceed 60 seconds when on peak load. The 160W model does offer 3.3V of 8A max load but still with recommendation of forced air ventilation.

To me it looks like most CT60 users are really pushing their luck. Also one must be careful with the actual power supply, I bought a 5A model which looks like a really bad choice ($60 AUD thrown away, damn it).

[10p6]

The Falcon with CT60e consumes less than 40 watts. It does not need a large Pico as many are using.

[mikro]

The Falcon with CT60e consumes less than 40 watts. It does not need a large Pico as many are using.

Yes, 3.3 * 8 = 26.4W for CT60. But I'm talking about the load which the PSU should handle. And if it says that it cannot handle more than 6A at given voltage then you're ignoring its specification and risk damaging it, no?

[10p6]

The Falcon with CT60e consumes less than 40 watts. It does not need a large Pico as many are using.

Yes, 3.3 * 8 = 26.4W for CT60. But I'm talking about the load which the PSU should handle. And if it says that it cannot handle more than 6A at given voltage then you're ignoring its specification and risk damaging it, no?

Well if you take 40 watts, and double it for inefficiencies (10 percent) and reserve, then you are still only at 80 watts.

[mikro]

I'm not an expert but I'd say if the manufacturer explicitly says that with this PSU you can have this many amps at this voltage and that many amps at that voltage, it doesn't really matter whether the overall power consumption falls within the limit.

[10p6]

I'm not an expert but I'd say if the manufacturer explicitly says that with this PSU you can have this many amps at this voltage and that many amps at that voltage, it doesn't really matter whether the overall power consumption falls within the limit.

Well Motorola specs list the 68060 at 5 watts max, so another 20+ watts for Ram and logic is a lot.

[mikro]

I didn't make those numbers up. ;-) If Czuba, the CT60 creator, says it needs 8 amps, I certainly dont have a reason not to believe him. Same for the PSU manufacturer.

[10p6]

I didn't make those numbers up. If Czuba, the CT60 creator, says it needs 8 amps, I certainly dont have a reason not to believe him. Same for the PSU manufacturer.

Well you could always just get a watt meter and plug it into the wall and see what it pulls. I already know what the Falcon generally uses, so I take it the CT60 creator listed this out of abundance of caution. 8 amps on the 3.3 rail is still only about 27 watts, so with the 13 or so watts for the Falcon, it is still around 40 watts maximum. If you are running a mechanical HDD then at worst that is going to add about 11 watts, but I imagine you are using an CF or SD which is minimal. Personally I still think an 80 watt PSU would be fine.

http://www.rapidtables.com/calc/electri ... ulator.htm

[mikro]

Do you know the difference between load and power consumption? By your logic having a 12V/1A PSU is the same as having 5V/2.4A PSU, they both produce 12W so what's the deal, we can use either of them, right?

Same for the PicoPSU: if the manufacturer says it can handle peak loads of 3.3V/8A, 5V/8A and 12V/10A for max of 60 seconds, max loads of 3.3V/6A, 5V/6A and 12V/7A with the note forced air ventilation is required unless you de-rate the output by another 20% (that makes 3.3V/4.8A) I think it makes one hell of a difference even if it's officially a 120W PSU.

[wongck]

I do not have a CT60e but this is my experience with the CT63.

I use an full-sized small external PSU for my CT63 and it is rated at 80W output.
I also run the CTPCI with an ATI graphic card and an external 5" HDD as well.
It works very well.

So 120W is plenty.

[mikro]

Guys, you're missing the point. The most important factor is what load it can take. It's cool it works for 10A * 12V = 120W but if 3.3V rating is "6A tops", it absolutely doesn't matter what the sticker says.

[Trixster]

I am no expert on psu's and such, but why does the falcon and CT60e require so many amperes?

Amiga 1200s outfitted with 060 accelerator boards and mechanical hdd's work ok with standard 3A and 4.5A stock amiga psu's

http://www.ianstedman.co.uk/Amiga/amiga ... plies.html

[dhedberg]

Guys, you're missing the point. The most important factor is what load it can take. It's cool it works for 10A * 12V = 120W but if 3.3V rating is "6A tops", it absolutely doesn't matter what the sticker says.

I get what you're saying mikro, and I agree with you. But my guess is that the stated 8A on the 3.3 rail is the maximum peak load for the CT63? It seems too high for a continuous load. It would be good if somebody could measure the amps on the 3.3 rail of a CT63/CT60e equipped Falcon.

[joska]

I would be very surprised if the CT60 alone use 25W. That's more than my entire Afterburner/Eclipse/spinning disc equipped Falcon does. I'll measure the amps when I get my CT60e up and running.

[1st1]

I am no expert on psu's and such, but why does the falcon and CT60e require so many amperes?

Amiga 1200s outfitted with 060 accelerator boards and mechanical hdd's work ok with standard 3A and 4.5A stock amiga psu's

http://www.ianstedman.co.uk/Amiga/amiga ... plies.html

It's anyhow different.

The 68060 and I think also those Xilinx FPGA chips are running with 3.3V. (The FPGAs are 5V tolerant to work with signals of the Falcon mainboard)

The PicoPSU is following the ATX stadard and so it directly provides 3.3 Volts. It also provides 5V and from the power inlet it gets already stabilisized 12V from the external power supply.

So the PicoPSU has all voltages to supply processor, falcon mainboard and drives. 3.3V, 5V and 12V. (It also has -5V and -12V but that is not required by Falcon and ct60(e).

You have to understand, it's very important that the power supply has to supply the system with the correct voltages and amperes.

You can have a powersupply with 90 Watts which has 30 Watts on 5V, and 30 Watts on 12V and 30 Watts on 3.3V. Thats 6A on 5V, 2,5A on 12V and 9 A on 3,3V. You also can have 90 Watts as 10W on 5V (2A), 10W on 12V (0,83A) and 70W on 3,3V (21A), and so on, any combination which is together 90W. The first given example would be ok 3,3V and it also has enough on 5V. Because 9A is more than 8A. The second example is fine on 3,3V as it has 21A which is much more than 8A. But the 5V 2A would be too weak to support all the falcon logics. The seocond would not supply stable the whole system.

You see, 90 Watts is not 90 Watts. It must be weighted correctly.

Amiga 1200 power supply is totally different. The original power supply only provides 5V, 12V and -12V. In total it's just 25 Watts. 68060 3.3V 8A maximum would already be more than these 25 Watts, so such turbocards already would run the power supply overspec, so I think they have some undocumented reserves. But these power supplys have no 3.3V which are needed for the 68060. Also the trapdoor connector has no -3.3V. So the turbocard in the trapdoor has to take the 5V or 12V and regulate it down to 3.3V. So they have voltage regultor components, capacitors and so on. But anyhow it looks like the amiga powesupply runs overspec with such a turbo card.

[mikro]

I get what you're saying mikro, and I agree with you. But my guess is that the stated 8A on the 3.3 rail is the maximum peak load for the CT63? It seems too high for a continuous load. It would be good if somebody could measure the amps on the 3.3 rail of a CT63/CT60e equipped Falcon.

Well, that's why I asked. ;-) I'd do it by myself if I had a "proper" ATX PSU but measuring amps on PicoPSU isn't exactly easy. To be honest, I even don't know how would I do that since you basically need broken circuit (PicoPSU's 3V rail -> multimeter -> CT60e) if I'm not mistaken.

[1st1]

I get what you're saying mikro, and I agree with you. But my guess is that the stated 8A on the 3.3 rail is the maximum peak load for the CT63? It seems too high for a continuous load. It would be good if somebody could measure the amps on the 3.3 rail of a CT63/CT60e equipped Falcon.

Well, that's why I asked. I'd do it by myself if I had a "proper" ATX PSU but measuring amps on PicoPSU isn't exactly easy. To be honest, I even don't know how would I do that since you basically need broken circuit (PicoPSU's 3V rail -> multimeter -> CT60e) if I'm not mistaken.

Yes, you are reight, you need to put your amperemeter between the connector of the picopsu and the board.

There are cables which can extend the length of an atx psu cable, like this: http://www.ebay.de/itm/Stromkabel-24Pin ... SwA3dYZnG0

3.3V is using the pins 1,2 and 11 of the ATX connector. You need to cut all of them and put the amperemeter in between. Or cut only one, put the amperemeter in between and multiply the value with three. It should be enough exact.

[mikro]

There are cables which can extend the length of an atx psu cable, like this: http://www.ebay.de/itm/Stromkabel-24Pin ... SwA3dYZnG0

3.3V is using the pins 1,2 and 11 of the ATX connector. You need to cut all of them and put the amperemeter in between. Or cut only one, put the amperemeter in between and multiply the value with three. It should be enough exact.

Ordered but it will take a while to arrive from Hong Kong so if anyone has a real ATX PSU and/or possibility to purchase it sooner, feel free to try it out.

[Ektus]

Some numbers from my fully equipped CT63 Falcon with CTPCI and a couple hard drives:
Total consumption during power-up: around 100W
Total consumption when sitting idle: 75W
The above measured from the wall socket.

Amperage on 3,3V line to CTPCI: approx. 2,3A (7,6W)
This is with four cards: graphics, network, firewire and usb
Amperage on 3,3V line to CT63: approx. 1.9A (6,3W) (three orange lines)
Amperage on 5V lines to CT63: approx. 2.3A (11,5W) (four red lines)

Measured with a clamp meter, make EXTECH, distributed by Conrad Electronics, model EX730. Thus, I had no need to cut any lines, just some zip ties to separate the lines

The numbers are when sitting idle, don't know how much it would be when running under load. CPU frequency is at 95MHz.

Regards
Ektus.

[troed]

Thanks! Then I don't think regular CT60e users need to worry about picoPSU at 60-80W

"a couple hard drives"

[Ektus]

156.3GB IDE Hard Disk (ExcelStor J81)
4.28GB SCSI Hard Disk (Conner CFP4207S)
100MB SCSI ZIP
IDE DVD drive
SCSI card reader
Floppy
There's room to spare in the tower case (currently occupied by some older, smaller hard drives that are not connected)

I don't know the efficiency of the power supply, though. I believe it may be 10 years old or more, it's a PowerMan FSP300-60BTV (PF) rated 28A at 3.3V, 30A at 5V and 15A at 12V.

[1st1]

That power supply seems not to run effektive. 100 Watts Input and only about 40 Watts out (on 12 maybe another 20 Watts estimated) Looks like the PSV Produces a lot of Heat for nothing. You should consider a more effektive one.

[Ektus]

I didn't measure the power usage of the drives, but you're right, it might be better to replace it with a more modern one. The data sheet (http://www.fspgroup.com/Catalog_PDF%5CA ... -60BTV.pdf) says something about minimum 65% efficiency, but it may be not the exact same model (no PFC, the picture doesn't show the power switch my unit has).

[joska]

Rodolphe Czuba says on his website:

CT63 needs a voltage of 3.3V and 8 Amperes at least for the 060, the SDRAM, the 060 BUS port, the logic and the buffers

From https://mikrosk.github.io/ct60tos/ctpci/CTHG.pdf (also from Rodolphe):

ct60 power consumption.png

Quite a bit less than 8A I think

Maybe the power-up problem some people have with certain PSU's is that 1.3A is too little for the PSU to start up? Most PC's draws a lot more current at 3.3V than this.

[mikro]

Jo, that's a great find! I had no idea this kind of data is there. I really wonder where he got that 8A from then.