Using a picoPSU: tired of the problems. Please help.

[Amiga1992]

The AC adapter came with the thing. It's some generic AC adapter, says it outputs 12-14V, 5.00-4.28A (TYP 12V 5.0A).
EPS Inc. Model: F10603-C. 60W AC Adapter

The picoPSU is a 120W model, both of them are. The only thing common to all this setup is the AC Adapter. Now I feel scared something might have broke into my two Amigas, but I have no regular power supply to test them with Will have to try and nab one on eBay or something. I wish I knew someone locally with an Amiga!

[voyager]

Again, try to put some load on the 3,3 volt line, I think it wil turn on.

[Amiga1992]

I am using Stedy's picoPSU adpater. I should NOT need anything else, everybody has been using these.

Perhaps Stedy the man can give me a help here.

[edit] I measured the AC adapter's voltage. It's giving out 12.48V. What I can't seem to measure is the amps.
I am totally stumped. I just won an A500 PSU on ebay. Wasted 10 pounds on it. really pises me off but I need to check my Amigas are A-OK.

[voyager]

Not all psu wil act the same.

[Amiga1992]

What does that mean?
I meant that now I am using an approved, working adapter used by many, also with a psu that is being used by many with that same adapter. It HAS to work and Stedy's adapter is made FOR picoPSUs.

[Stedy]

Hi

I have only experienced issues with late 90's model ATX psus if there was no load on the +5V supply. I use a 90W picoPSU supply with my A600/A500 or A1200. Now onto fault finding.

Akira can you measure the power supply outputs without the amiga connected and with it connected? Use the screw terminals to measure the supplies.

Next test is to unplug the picoPSU but plug the adaptor into the Amiga. Again using the screw terminals and a multimeter, measure the resistance between the +5V supply and ground it should be greater than 10 ohms. Repeat this measurement for the +/-12V supplies.

To check the picoPSU can you plug it into a low power PC?

Let me know the results and we will proceed from there.

Ian

[Amiga1992]

OK I did the tests, here are the results

picoPSU 1 on its own:
+5v -> 5.00V
+12V -> 12.48V
-12V -> -13.50V

picoPSU 2 on its own:
+5V -> 5.00V
+12V -> 12.48V
-12V -> -13.50V

AMIGA 600:
When picoPSU is plugged, readings:
+5V -> 0V
+12V -> 0~0.02V
-12V -> 0~-0.04V

Resistance value: 106~110 ohm on +5V. I am getting no reading connecting +/-12V
(I set the multimerter on 200 ohm scale, I hope that is correct, it was the lower reading. I never did this one)

AMIGA 1200:
When picoPSU is plugged, readings:
+5V -> 0V
+12V -> 0~0.02V
-12V -> 0~-0.04V (or similar, it fluctuated a bit, but similar readings to the A600 ones)

Resistance value: 130~136 ohm on +5V. I am getting no reading connecting +/-12V


Now I went and did an extra measure, I measured the current with the Amiga on. What I did was turn the picoPSU on with the switch and then plug it into the A600. As I said before ,this makes the A600 seem to boot up, but I get no video on screen.
Readings:

+5V -> 5.00V
+12V -> 12.39V
-12V -> -10.99V


Did some more, changed the multimeter to 2000 scale, and got readings of resistance on the 12V lines

A600:
-12V and Gnd: 1335
+12V and Gnd: 1355
+12V and -12V: 662/663

A1200:

-12V and Gnd: 1242
+12V and Gnd: 1013
+12V and -12V: 634/635/637
Any idea of what is going on?


I was thinking, in all the setups, the Amigas are different, the picoPSUs are different and even the ATX adapters are different. The only common factor to any setup is the AC Adapter AND the Amiga PSU cable. Could it be that either of those is faulty? Maybe the Amiga PSU cable? I took it from a working german 220V Amiga PSU.

any help really apreciated.
I cant connect the picoPSU to a PC because I have none

[roy bates]

what switch are you using with stedys power adaptor,because it has to be a momentary action push to make switch(just like a reset button)not on off type.

have you wired the amiga lead properly(sounds silly but sometimes the colour codes are different on each lead.(test the voltage on the amiga cable end to see.)

[_psy]

try to plug the power adapter to another power socket in the house and even try to power the thing up on another house and remove the switch roy is right that's all i can think of

[Amiga1992]

Originally Posted by roy bates

what switch are you using with stedys power adaptor,because it has to be a momentary action push to make switch(just like a reset button)not on off type.

Nope, the board has a JUMPER to change between momentary and rocker. I set the jumper to rocker, because that is what I have.

have you wired the amiga lead properly(sounds silly but sometimes the colour codes are different on each lead.(test the voltage on the amiga cable end to see.)

I have checked this a million times, I said it already. The pins are correct.

Plugging the power adapter to other socket? Another house?? Seriously? come on.

Awaiting Stedy's input on the matter...

[roy bates]

i know this sort of thing will make you angry,but im only trying to help i cant tell how you have wired it from the picture you posted,obviosly you are getting power from it with no load,but it wont turn on with it connected to the amiga.so im thinking.....

have you tried it with a standard amiga power supply to check your amiga actaully works?


best of luck.

[Amiga1992]

I'm not angry at anything but this issue, but if you would actually read the thread -through-, you will understand my answer to the latest suggestions.
No beef mate, just trying to steer this through to solving it.

Waiting for Stedy's input...

[roy bates]

Originally Posted by Akira

I'm not angry at anything but this issue, but if you would actually read the thread -through-, you will understand my answer to the latest suggestions.
No beef mate, just trying to steer this through to solving it.

Waiting for Stedy's input...

no probs,have you tried the picu under load?(without the amiga)

wire 12 volt bulb's to the output of the power lines and see if it powers up.


plus if your using a 120 watt picu you need a 90 watt 12 volt source to power it.minimum

[thgill]

Originally Posted by roy bates

plus if your using a 120 watt picu you need a 90 watt 12 volt source to power it.minimum

Are you familiar with pico psu at all or used one? I ask because what you said is wrong. The 120 watt pico is commonly sold and used with the 60 watt brick. Obviously that lowers it's max wattage output, but it works fine. Even the manual says its minimum input is 12v at 2 amps.

Mini box even sells it with a 60 watt brick for lower power requirement projects.

The brick could be defective but otherwise will power the 120 watt pico just fine.

[roy bates]

Originally Posted by thgill

Are you familiar with pico psu at all or used one? I ask because what you said is wrong. The 120 watt pico is commonly sold and used with the 60 watt brick. Obviously that lowers it's max wattage output, but it works fine. Even the manual says its minimum input is 12v at 2 amps.

Mini box even sells it with a 60 watt brick for lower power requirement projects.

The brick could be defective but otherwise will power the 120 watt pico just fine.

yes i am,i said that because if you use a 60 watt 12 volt supply the output will probably be 60 watts not 120.

to be perfectly honest with you, whats the point of a 120 watt supply if its not 120 watts but 90 or 60,the only way this will put out more is to use a 12 volt 10 amp supply,or plug it into a cigerete lighter in your car.

[_psy]

yes the most possible thing if wires are alright is that the brick is defective and under load can't deliver that's why you get readings without load and 0 when you connect the amiga.

[roy bates]

Originally Posted by _psy

yes the most possible thing if wires are alright is that the brick is defective and under load can't deliver that's why you get readings without load and 0 when you connect the amiga.

what im thinking is there might be a short in the wiring at the amiga end that makes the psu crowbar protection kick in.or........

to eleminate that im asking for it to be tested without the amiga on the other end of it and it be "under load",witch would eliminate that from the equation.


to be honest 60-90 watts is more than enough for a 1200 anyway.

[_psy]

yes something with 12v input like a car stereo (and as already suggested a lamp is the best tester )

[Stedy]

Hi,

Reading through the resistance measurements, the A600/A1200 does not have a short on any power supply. That's a good start.

Have you checked that the correct voltages are on the correct pins of the Amiga power plug? The diagram was posted earlier by _psy.

It appears that the picoPSU is shutting down when plugged into the Amiga.

I have a 90W picoPSU with a 60W mains adaptor and that easily powers an A1200 + Apollo 1240 + CDROM + Scandoubler. This should not be the problem.

As roy bates suggested, can you connect a 21W car stoplight bulb to the +12V and then the +5V outputs of the picoPSU (use my adaptor to get access to the power if necessary)?

The pcioPSU manuals do not specify any minimum loads, it is actually quite rare for a modern buck converter to need a minimum load to be stable. picoPSU manuals available here: http://www.mini-box.com/picoPSU-90

Do you have a friend with a PC who would let you test your Amiga using their ATX PSU?
Could you obtain a cheap 2nd user ATX PSU for testing?

The fact that you mentioned you wired the +5V and +5VSB signals together does worry me, you may have irreprably damaged the picoPSU.

Ian

[roy bates]

if i can possibly make one more suggestion,if you try a freinds atx supply please please dont try this on a "dell" atx supply there not wired to atx standards.(they power up the same way ps-on to ground or low signal, but some of the other power rails are wired differently 12 volts on the 3.3 volt line etc)so agian please be aware of this if you try it.