Power supply spec

[John Kennedy]

I was lucky enough to get one of the Altair 8800b kits, and love it.

I've been using it using the USB port to power it.

What would be specs be for an external power supply?

thanks

[Walt Perko]

Hi, 

I'd guess the same as the Altair-Duino Pro ... a + center 9V d.c.  1A output.  

[Chris Davis]

I use a 9v 1A with a 5.5 x 2.1mm center positive connector.  That's a standard Arduino power adapter.

[John Kennedy]

Thanks both. I found the 9v supply that came with it, but I had discounted it as I was ASSuming the one I should be looking for would be 5v as there was no regulator on the circuit board.

I forgot the Arduino has one built-in!

For whatever reason, the system doesn't power-up with it connected, so time to break out the multimeter :-)

thanks!

[John Kennedy]

Yup, bad solder joint! All good now.

[John Kennedy]

Thanks! I will be super cautious to use one or the other!

On Sunday, July 31, 2022 at 7:37:19 AM UTC-7 furba...@gmail.com wrote:

warning: if you plan to use the power supply and have it plugged into USB to use as a terminal or just for file transfer: 

The due will switch automatically to USB if you flick the power switch off. then when you turn the power on you could blow the Arduino power supply. 

Use a USB power blocker, or you can make your own it just disconnects the Positive power lead of the USB cable.

example of a power blocker:

https://www.amazon.com/PortaPow-USB-Power-Blocker-Only/dp/B0937B95QK

I've blown a power supply this way. This also keeps the Power switch on the Altair-duino working without it hooked up to USB you cannot shut the power for a cold boot. 

if you have made the mistake of flicking the power switch off while connected to USB and the wall Wart, do not flick the power switch back on, unplug the USB cable first!

[Walt Perko]

Hi, 

I got these USB power isolators;  Great price for three USB Type-A isolators and one adapter for the micro-B connector.  They even have a 3D printed case around the connector to make them even nicer.  Great price!  $12 for three adapters!  

https://www.etsy.com/listing/1184029990/usb-power-isolator-for-3d-printers?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=USB+Power+Isolator+for+3D&ref=sr_gallery-1-1&sts=1&organic_search_click=1

On Sunday, July 31, 2022 at 7:37:19 AM UTC-7 furba...@gmail.com wrote:

warning: if you plan to use the power supply and have it plugged into USB to use as a terminal or just for file transfer: 

The due will switch automatically to USB if you flick the power switch off. then when you turn the power on you could blow the Arduino power supply. 

Use a USB power blocker, or you can make your own it just disconnects the Positive power lead of the USB cable.

example of a power blocker:

https://www.amazon.com/PortaPow-USB-Power-Blocker-Only/dp/B0937B95QK

I've blown a power supply this way. This also keeps the Power switch on the Altair-duino working without it hooked up to USB you cannot shut the power for a cold boot. 

if you have made the mistake of flicking the power switch off while connected to USB and the wall Wart, do not flick the power switch back on, unplug the USB cable first!

On Sunday, July 31, 2022 at 9:44:36 AM UTC-4 johntk...@gmail.com wrote:

[Walt Perko]

Hi, 

I thought I'd post a few photos of the USB isolators I got.  I got three of the USB isolators on the right with the green 3D printed enclosures and the one little adapter on the left;  

This is the isolator on my 1st Altair-Duino Pro computer;  

and this is the one on my 2nd Altair-Duino Pro computer;  

[Belknap K]

The Altair-Duino Pro with the IO Expansion can be operated at 5.4 VDC,
quite successfully.

I am not, at all, careful of the state of the front panel power switch. 
With, or without, VBUS present (USB Programmer's Port connected to a
host PC).

I keep the (Korad KD3005D) bench supply at exactly 5.4 VDC, fed to the
IO Expansion at the 2.1 mm barrel jack.