520ST & Pico PSU

[Dopy25]

I've seen a few posts about people doing it, but unsure if there are long term issues.

 

I should be ok to wire a Pico inside a 520ST as long as I wire it correctly internally, right? 

 

I am thinking of using some open space to leave the pico itself, and run the output wires to their solder points on the board where the power din is, and using a connector to have it breakaway so it is easy to remove. I may remove the power din too if I can't figure out another place to put the DC jack.

 

I do not have the ST yet. It is in the mail but does not come with a PSU so I am looking for alternatives since originals are pricey. 

[TGB1718]

Yes, you can power the Pico from the 5V line, make sure it's not too far off 5V as I believe

Pico's are very touchy with poor regulation.

 

I think you connect the 5V to VSYS pin 39 and obviously 0V to any of the ground pins.

[Dopy25]

@TGB1718 My apologies. I want to power the ST from a pico PSU, like one of these:

 

https://www.amazon.com/RGEEK-24pin-Input-Output-Switch/dp/B07WDG49S8/?_encoding=UTF8&pd_rd_w=R6xi2&content-id=amzn1.sym.bbb6bbd8-d236-47cb-b42f-734cb0cacc1f&pf_rd_p=bbb6bbd8-d236-47cb-b42f-734cb0cacc1f&pf_rd_r=5RE9WE3YPMV7Q1ZQSXC0&pd_rd_wg=V2PZn&pd_rd_r=0212adb5-61d7-4b50-b0c9-48e6ee9523a1&ref_=pd_gw_ci_mcx_mi

Edited June 15, 2022 by Dopy25

[TGB1718]

24 minutes ago, Dopy25 said:

My apologies. I want to power the ST from a pico PSU, like one of these:

My bad ? got the wrong end of the stick

[TGB1718]

A few things I can see, obviously you need a good 12V power supply for this device.

By the look of it, it's a "buck" device so it's going to be running at some high frequency

which could cause problems and may require shielding or changing some of the 5V line

capacitors in the ST if you get any instability after fitting.

(in the 8 bit forum, some people have had issues with switching 7805 regulators in the PSU's of 1050 disk drives)

 

Also I assume you don't need RS232 as there doesn't appear to be a -12V line

 

[Dopy25]

4 minutes ago, TGB1718 said:

A few things I can see, obviously you need a good 12V power supply for this device.

By the look of it, it's a "buck" device so it's going to be running at some high frequency

which could cause problems and may require shielding or changing some of the 5V line

capacitors in the ST if you get any instability after fitting.

(in the 8 bit forum, some people have had issues with switching 7805 regulators in the PSU's of 1050 disk drives)

 

Also I assume you don't need RS232 as there doesn't appear to be a -12V line

 

I have a few 12v PSUs that would be great for this, ranging anywhere between 2-5 amp.

 

I could definitely do a recap on it if I have issues or if they are bulging, so that shouldn't be too much of an issue. I can also create a shield of some sort around the PSU.

 

I did read the issues with replacing the 7805 but I don't have any drives at this time so we can cross that bridge later. For now, I want to make sure the ST functions before I add peripherals, since they are not cheap. Problem is spending a ton of money on an outdated PSU for step 1.

 

It's ATX Pico PSU so it should have the same -12 line as a full size ATX supply on pin 14. Is the serial where the -12 needs? I read that -12 was for audio.

 

Please forgive me as this will be the first ST I will ever touch.

[TGB1718]

16 minutes ago, Dopy25 said:

It's ATX Pico PSU so it should have the same -12 line as a full size ATX supply on pin 14. Is the serial where the -12 needs? I read that -12 was for audio.

I thought it should have the -12V too, but there's limited information about it.

However, the + and - 12V goes to the 1488 (U14) RS232 driver chip only, sound comes from the YM2149 chip

which only has a 5V supply to it.

[Dopy25]

7 minutes ago, TGB1718 said:

I thought it should have the -12V too, but there's limited information about it.

However, the + and - 12V goes to the 1488 (U14) RS232 driver chip only, sound comes from the YM2149 chip

which only has a 5V supply to it.

So really I could get away with 5v 2-3a only, for testing purposes? I just want to know if it runs or not before diving much more into it.

 

If it will run on 5v only, I have a 5v psu for my 800XL I could use temporarily. I just didn't read anything that pointed to that. 

[TGB1718]

I have a 520STM with an original power "brick", it's rated at  5V 3A and +/-12V .03A so

if your 800XL PSU can push that much, should be ok to test with.

[Dopy25]

4 minutes ago, TGB1718 said:

I have a 520STM with an original power "brick", it's rated at  5V 3A and +/-12V .03A so

if your 800XL PSU can push that much, should be ok to test with.

I will check. It might be only 2 amps. If so I will look elsewhere. 

[Dopy25]

I found a cheaper, more viable option. I'll swap out the plug on this one. It seems to match the expected inputs.

 

https://www.ebay.com/itm/303116985646?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=hJo5wFBuQIe&sssrc=2349624&ssuid=tc6gnTeJTDi&var=&widget_ver=artemis&media=COPY

[Dopy25]

Well I got the PSU and modified it to work on the St, and modified a VGA cable, but I think something else might be off. I'm not sure this warrants a new topic since the title still applies.

 

I have absolutely no idea what I'm looking for when this thing boots. I started with power. I got an LED so I made a VGA cable. It might be an old cable since not all of the pins were populated. I'll buy a VGA breakout and try again, but I do have something on the screen so it is promising. I just don't know where to go from here. The only images I find have loaded desktops, not what I'm seeing here. Does this mean I don't have an operating system? Or does it mean something else is bad?

 

I do not have a mouse to do any further testing, but I made the rookie mistake of thinking I could navigate somehow with the keyboard. 

 

Any information/advice/tips are appreciated. 

[darwinmac]

As I recall, you can use Alt+the arrow keys to move the mouse. Since you are using a VGA cable, you will only see ST high resolution. 
 

If you don’t have a disk drive, you won’t see any drive icons. 
 

The screen you’re showing is a working GEM desktop in mono (high res) without any working disk drives. 
 

Without a working disk drive, the 520 is pretty worthless. If you are stuck with only high resolution (mono), there are only certain games you’ll be able to run. 
 

Bob C

[Dopy25]

@darwinmac

Perfect! So it's working as normal. That's great news. I just didn't know what to expect. It's the regular St so no drive, no RF, no composite. I wired up a VGA cable to test but had no idea what I was looking for. I am aware that the VGA will only carry mono. Now that I know this works, I can look into an SCART cable (and adapter) or other video method. It just came with no power or video so I had to come up with the basics before getting quality components. 

 

I will check on the alt/arrow thing. Thanks for the tip!

[TGB1718]

8 hours ago, darwinmac said:

As I recall, you can use Alt+the arrow keys to move the mouse.

Don't forget Atl-Ins acts as the mouse button, just press once to select an item or twice quickly to open an item

[Dopy25]

1 hour ago, TGB1718 said:

Don't forget Atl-Ins acts as the mouse button, just press once to select an item or twice quickly to open an item

That's great advice. Thanks!

 

Right now I don't have any drives, I'm just trying to see the TOS version, which I think I can find by navigating those options across the top. 

 

I'm trying to find out if the SD card options will work with my TOS version, whatever that may be. 

 

I'm going in steps instead of just throwing money at it for all the addons before knowing if it works. I'm not even sure if the keyboard works because I don't see a memo pad option like on the 8bit PCs.

 

 

Edit:

 

Well the Alt arrows thing did work so I guess that means my keyboard functions. But my hypothesis was incorrect. The TOS version is not shown for me at the desktop information screen.

 

Edited June 19, 2022 by Dopy25

[TGB1718]

2 minutes ago, Dopy25 said:

I don't see a memo pad option like on the 8bit PCs

No Memo Pad on the ST, straight to Desktop, without a floppy or hard drive, you can't do much

[Dopy25]

1 minute ago, TGB1718 said:

No Memo Pad on the ST, straight to Desktop, without a floppy or hard drive, you can't do much

I did read that. Kinda disappointed but that's ok. I'll grab an SD card solution for now. Definitely will be the cheapest option to get up and running. I just didn't know what to expect when it booted. Now I do, and I'm happy it even boots up at all!

[Dopy25]

Also unfortunately someone had been inside before and put the wrong screw in one of the front holes so it pushed a little spot up on the front, right in the center. It's no big deal but it is there. Other than that, I'm happy with it. 

 

Also when I went inside, I saw there are no mods of any sort. Looks like I need to get on that. Lol

Edited June 19, 2022 by Dopy25

[snarkdluG]

GEM never reports TOS version. Only copyright year. You can use sysinfo for more info. But you got TOS v1.00. TOS v1.04 is what you can get running without any problem on there and is recommended when using HDD.

[Dopy25]

33 minutes ago, snarkdluG said:

GEM never reports TOS version. Only copyright year. You can use sysinfo for more info. But you got TOS v1.00. TOS v1.04 is what you can get running without any problem on there and is recommended when using HDD.

Awesome. I don't currently have a way to run any software so I guess I'm looking into an SD card solution, and upgrading TOS.

Thanks for the info!

[masteries]

55 minutes ago, Dopy25 said:

Awesome. I don't currently have a way to run any software so I guess I'm looking into an SD card solution, and upgrading TOS.

Thanks for the info!

TOS 1.0 and 1.02 are supported via a custom SD card image if you will to use the low cost hard disk solution

 

However, this special SD card image will not be easily readable under Windows / Linux / Mac

 

 

As SnarkdluG suggested, TOS 1.04 is the recommended version for your machine;

as well with this TOS upgrade, the SD card can be a FAT 16 one, easy to read/write it using your PC

[Dopy25]

1 hour ago, masteries said:

TOS 1.0 and 1.02 are supported via a custom SD card image if you will to use the low cost hard disk solution

 

However, this special SD card image will not be easily readable under Windows / Linux / Mac

Just the person I was going to ask. That's perfect. Looks like I'll be able to start with that, and upgrade the TOS, and SD image down the road. Thanks for confirming, @masteries

[+DarkLord]

On 6/15/2022 at 3:25 PM, TGB1718 said:

A few things I can see, obviously you need a good 12V power supply for this device.

By the look of it, it's a "buck" device so it's going to be running at some high frequency

which could cause problems and may require shielding or changing some of the 5V line

capacitors in the ST if you get any instability after fitting.

(in the 8 bit forum, some people have had issues with switching 7805 regulators in the PSU's of 1050 disk drives)

 

Also I assume you don't need RS232 as there doesn't appear to be a -12V line

 

 

I'm curious about this...

 

At one point in time I was using a Pico 120w P/S to power my STacy. I fed the +5v into the 2nd floppy drive line and powered the

whole machine.

 

Now this has been awhile, so I might not be remembering it right so forgive me...but I thought I used a Lantronix UDS10 off the

serial port without problems...

 

Am I just remembering this wrong?

 

Thanks.