Issues with ACA620 and Gotek

[Amiga1992]

As discussed in the FlashFloppy thread, I am having issues with my ACA620 and my Gotek emulator.

I have only noticed it so far on one game, but I wonder what it is and if I should be worried.

Description of the issue, with photos, here:
http://eab.abime.net/showthread.php?...34#post1180134
http://eab.abime.net/showthread.php?...68#post1180568

As said over there, problem goes away as soon as I boot with the ACA620 disabled (by jumper).

Anybody else can replicate this problem, or anybody knows what it could be and offer ideas to fix it?

Thanks

[Jeff_HxC2001]

99% sure that this is a power supply issue, and not a "bug".

I suppose that your 12V is unloaded without the floppy drive ? Try to load the 12V power line with something with a resistor drawing 0.5 Watt for example, your power supply should be stable again. It is probably actually unbalanced between the 12V and +5V line. (i don't know how is powered your accelerator board but for sure it may participate to the issue...)

btw replacing a part by a new one using less power lines and/or current may seems a good thing but in fact it is not at all in some systems cause of this issue. This is not only an Amiga issue...

>and if I should be worried.
yes. ac/dc power supplies don't like to be unloaded and they theoretically didn't work properly in these cases

Other point to check : Is the power supply able to support the current drawing variation of these modern usb stick ? The current drawing may change from 0 mA to 500mA in some nano seconds. These good old power supply are for sure no designed for this, and the gotek is for sure not enough decoupled. Try to add a big capacitor (1000uF or more) near the gotek +5V power line...

And : Is there enough power margin available on the the +5V line with the ACA620 attached ?

And the last : how old are the capacitors into the into your power supply ?

Your issue is probably a combination of all of this

btw i am almost sure that the hxc firmware didn't show this issue because the usb stick is not polled all the time with adf files. Once a track is cached, the usb stick is not accessed anymore. Have you a gotek with this firmware to test it ?

[Amiga1992]

I have an 80W picoPSU as I said in the thread I linked to, not an "old power supply" (dunno why you thought I did). There is no chance it is underpowered or that it has capacitor issues because it's only a couple of years old.
It has a shit ton more power than this simple Amiga will ever require, and you would think a regular floppy drive draws more power than a Gotek, and this issue does NOT happen when a regular floppy drive is connected.



As I mentioned before I would appreciate tests done by other people having an ACA620 and a Gotek, to see if other setups display the same problem.

[Jeff_HxC2001]

Originally Posted by Akira

I have an 80W picoPSU as I said in the thread I linked to, not an "old power supply" (dunno why you thought I did).

Because for sure there is a large quantity of Amiga machines are powered with shitty power supply...

Anyway a first simple test is maybe to try another power supply to sure, isn't it ?

And having a picopsu doesn't mean that all is decoupled enough/correctly in all your system... what about the power supply wires and connections ? is your motherboard recapped with the right parts ? (same capacitor ESR ?)

Other question : Did you keep the usb stick plugged into the drive during the game ? What happen if you remove the stick ?

Originally Posted by Akira

It has a shit ton more power than this simple Amiga will ever require, and you would think a regular floppy drive draws more power than a Gotek, and this issue does NOT happen when a regular floppy drive is connected.

That's what i am trying to explain you into my first post : to have a good regulation DCDC & ACDC power supplies need a minimum of current consumption. under this, you may have undershot/overshot and others strange effects. So yes, this psu is not designed for an Amiga, it was designed to power pc motherboards drawing more current. So It will not surprise me if this is the cause of the issue here.

The current drawing of a gotek and of a floppy drive is completely different : the current drawing of a floppy drive is somewhat flat while not starting up and head stepping. A gotek will present current peaks at each usb stick access and this all the time. some high speed usb stick may generate strong current "glitches" :

http://www.anandtech.com/show/10163/...les-usbctkey/3

If the system is no decoupled/filtered enough to support this, you may have these glitches on the video and/or audio outputs...

EDIT : Oh Wait !!!

<<Trying to use mini-box picoPSU-120 to power Amiga but -12v rail is out of ATX compliance>>
https://www.techtravels.org/2015/02/...tx-compliance/

Originally Posted by Akira

As I mentioned before I would appreciate tests done by other people having an ACA620 and a Gotek, to see if other setups display the same problem.

good luck then !

[Jeff_HxC2001]

btw which usb stick brand and model are you using ?

[Amiga1992]

Originally Posted by Jeff_HxC2001

Because for sure there is a large quantity of Amiga machines are powered with shitty power supply...

Yes, but I described my problem in detail in the posts I linked and I mentioned which PSU I had.

Anyway a first simple test is maybe to try another power supply to sure, isn't it ?

In that system I cannot do that, and I don't want to move the ACA620 because those things are a fucking bitch to install and remove without risking the CPU connection. So I am stuck with the PSU I have for the time being.

This is why I ask of other people having an ACA620 and a Gotek (there MUST be some!) to test, so if they come out with results different to mine, we can certainly start putting blame on the PSU.

And having a picopsu doesn't mean that all is decoupled enough/correctly in all your system... what about the power supply wires and connections ?

What about them?

is your motherboard recapped with the right parts ? (same capacitor ESR ?)

It is perfectly recapped by a pro who put back exactly what the machine had to begin with.
Capacitors are NOT a problem.

Other question : Did you keep the usb stick plugged into the drive during the game ? What happen if you remove the stick ?

Hmm... I thought I removed it, but I can't remember now because I did so many tests, will check again.
All this testing made my keyboard membrane bit the dust for good so I am quite pissed at this system in general and not really looking forward to do any more tests for the time being, so I am giving myself some days to rest from last weekend's nightmares


Now:

to have a good regulation DCDC & ACDC power supplies need a minimum of current consumption. under this, you may have undershot/overshot and others strange effects.
[...]
EDIT : Oh Wait !!!

<<Trying to use mini-box picoPSU-120 to power Amiga but -12v rail is out of ATX compliance>>
https://www.techtravels.org/2015/02/...tx-compliance/

This sounds like an issue I had with an older picoPSU in the past, it wouldn't even power up unless I specifically plugged its power connector directly to the floppy drive instead of connecting the floppy drive to the motherboard power connector. This issue does not happen with newer models.

However, the article you linked to talks about -12V. -12V on the Amiga is as far as I know only used for audio. It shouldn't be affected by the floppy or mess with the video.


Anyway, someone with ACA620 and Gotek please come forward so tests can be made

By the way on the FF thread you said "probably the green background helps you to see the problem" and no, this is not the issue here. Only that game shows this issue. I tried many, and my eye aren't that shitty that I wouldn't notice such a blatant aberration.

[Jeff_HxC2001]

Originally Posted by Akira

By the way on the FF thread you said "probably the green background helps you to see the problem" and no, this is not the issue here. Only that game shows this issue. I tried many, and my eye aren't that shitty that I wouldn't notice such a blatant aberration.

From your captures and pictures it look like there is a brightness change during some scanlines. The only thing that may produce and explain this is a power supply voltage variation. And since the gotek usb port is not filtered and current limited at all, the usb stick can produce such voltage drop.

Anyway i am quite interested by the final conclusion of this issue !

[Amiga1992]

I don't really know if it is a brightness change but I did indeed think at first sight that it looked like a power issue. When one of my A600 was recapped wrongly, when the floppy disk drive was accessed, it would create similar lines on screen (even when "clicking", so what you said about it creating spikes when stepping is true, and noticeable in fragile setups).

But I would expect to see this issue on every game, actually, all the time, yet, it doesn't work that way. You mentioned the power spikes on USB sticks, but would those happen on "disk" access or all the time? Because when I load the WHDLoad version of SWOS, there is absolutely NO disk access to be had. So if they happen all the time, why are they NOT present on ANY other screen?

[fordav1]

one thing you haven't mentioned... did you try disabling the cache in the early start-up menu? I've found doing that will "fix" most game issues.

[Jeff_HxC2001]

Originally Posted by Akira

I don't really know if it is a brightness change but I did indeed think at first sight that it looked like a power issue. When one of my A600 was recapped wrongly, when the floppy disk drive was accessed, it would create similar lines on screen (even when "clicking", so what you said about it creating spikes when stepping is true, and noticeable in fragile setups).

But I would expect to see this issue on every game, actually, all the time, yet, it doesn't work that way. You mentioned the power spikes on USB sticks, but would those happen on "disk" access or all the time? Because when I load the WHDLoad version of SWOS, there is absolutely NO disk access to be had. So if they happen all the time, why are they NOT present on ANY other screen?

usb access:
cortex firmware: all the time.
ff : not sure at all, but i think that this is all the time too ?
hxc : if adf, only on track change. once the track is cached, there is no more usb access.

For the other screen, i really don't know. this maybe related to a specific video mode or something like this.

Anyway try to reproduce the issue, then remove the usb stick and if this doesn't solve the issue, try to disconnect the gotek power supply connector (if possible...).

[Jeff_HxC2001]

And you forgot this :

Originally Posted by Jeff_HxC2001

btw which usb stick brand and model are you using ?

this is maybe important and interest me !

[Amiga1992]

Sorry, yes I forgot. Because the USB stick is nobrand garbage
If there is any way to extract more info from it let me know so I can provide you with it.

Originally Posted by Jeff_HxC2001

Anyway try to reproduce the issue, then remove the usb stick and if this doesn't solve the issue, try to disconnect the gotek power supply connector (if possible...).

I will test this later and post again.

[fordav1]

you can get the VID (Vendor ID) and PID (Product ID) of most USB drives using software.
ChipGenius is a good one but there are plenty of others....
http://xpenology.me/how-to-see-the-v...vid-pid-stick/

There's another listing that lists all the VID/PIDs and the company/model.
http://www.linux-usb.org/usb.ids

Unfortunately unscrupulous Chinese sellers have exploited various software tools to force USB drives to look bigger than they actually are and sell (for example) 64GB USB drive with is really only 8GB. In some cases it can be reversed using other software tools, but in some cases not because the VID/PID or flash type info has been manipulated so those reversal tools fail.

[Amiga1992]

OK I just went and did the tests as askedby Jeff.

I booted up SWOS 95-96 from the Gotek, started a game, the lines were there alright.
I removed the USB stick, and the lines were still there.
This is where it gets weird.

I decided "here goes nothing" and unplugged the Gotek power cable. LINES STILL THERE.
I was like "WTF!!!!?????" so I unplugged the data cable. LINES STILL THERE.

At this point I decide that it might not be the Gotek after all and that it is the ACA620 on its own. So I put back the original floppy drive and I transfer those SWOS images to floppies to test.

I start the game, and there's NO LINES

So what's next?
Whatever happens when the Gotek is connected, it remains even after physically removing it from the system.
What wizardry is this?!?
I would have assumed that if it is a power issue, it would disappear as soon as I unplug the Gotek!

[Jeff_HxC2001]

Funny issue .

Is the floppy drive using the +12V line ?
Can you try to boot the game from floppy and then disconnect the floppy power and data ribbon ?
if the lines are appearing at this moment, just reconnect the floppy power to see if they disappear.

[Amiga1992]

This is driving me crazy.

Yesterday I left the machine on for a while and then went and tested SWOS with the Gotek and the lines weren't there.

It would be very weird to have capacitor issues on the motherboard as this was serviced about 3 years ago.

I also think I noticed the lines on Prime Mover, but the road is grey so it's hard to see.

I will have to give more tests, will try that floppy stuff, but I don't think it will create the lines.

[Amiga1992]

OK I am pulling my hair out

Unplugging the floppy drive while the game was running didn't immediately show the lines. But it did after a while.
Fun fact though: I also got lines when the drive was plugged, at some point.
So I thought "maybe I should power the drive from the PSU itself", I went and got the appropriate cable and powered the floppy from it and nothing changed. Tried with the Gotek and same thing. I get lines.

At this point I cannot really discard capacitor fault. This is really really fucking annoying. But I thought capacitors would last more than just 3 years.
Seems like when you leave the machine on for longer the lines tend to disappear which is why I doubt capacitors. But this is just my feel and not science. I don't have the means to test scientifically and the lines change intensity all the time, apparently for no reason at all.

[Jeff_HxC2001]

Originally Posted by Akira

OK I am pulling my hair out

Unplugging the floppy drive while the game was running didn't immediately show the lines. But it did after a while.
Fun fact though: I also got lines when the drive was plugged, at some point.
So I thought "maybe I should power the drive from the PSU itself", I went and got the appropriate cable and powered the floppy from it and nothing changed. Tried with the Gotek and same thing. I get lines.

At this point I cannot really discard capacitor fault. This is really really fucking annoying. But I thought capacitors would last more than just 3 years.
Seems like when you leave the machine on for longer the lines tend to disappear which is why I doubt capacitors. But this is just my feel and not science. I don't have the means to test scientifically and the lines change intensity all the time, apparently for no reason at all.

This may be a capacitor fault, but i think that this is more a PSU fault. As i explained earlier an not-loaded-enough DCDC/ACDC PSU may behave strangely and you said yourself :
<<It has a shit ton more power than this simple Amiga will ever require>> -> As electrician, this sound not good to me.

The floppy drive probably draw some current on the 12V & 5V which stabilize a little bit the PSU. If possible you should try to connect an old 3"1/2 Hard disk requiring both 12V & 5V and see what happen.

[Amiga1992]

I talked with who serviced my board and there's no way this is a capacitor issue. They are too new. So let's scratch that for sanity's sake!

On the tests above, I tried to load the PSU properly, but maybe none of the things I plugged were 12V (the floppy and a fan). I don't think I have 12V devices around like an old hard disk, so I am a bit stuck for choices now. Also pissed off at this machine and this stupid problem :P

Now, if the PSU needs more charge, why is it this problem goes away when I disable the ACA620 then? There's too many contradicting factors in this issue.

[Jeff_HxC2001]

Originally Posted by Akira

Now, if the PSU needs more charge, why is it this problem goes away when I disable the ACA620 then? There's too many contradicting factors in this issue.

Possible unbalanced output issue. Some PSU with multiples outputs need a minimum of current on all outputs...

For the ACA620, this is pure speculation, but since it was designed quite recently, it is possible that the design draw less current than original Amiga...