PCB Build - Progress - Post your Pics here :-)

[Atarian Computing]

Nope.. TOS cannot run without RAM.

Darn. A longer wait for me then. Thanks Exxos.

I'm in the same boat. I've got one F030 card that should be on its way.

[PhilC]

Ok, so once we are all ready, do we have a plan or procedure that we think would be best for starting up the new board. For instance, removing chips and testing that all the voltages and clock waveforms are in the right place first?

I have to confess, this is the biggest "from scratch" project i've built. I'm more into repairs or stuff the size of the PAK boards.

[exxos]

Most of the chips have to be in place to work, aside from maybe the 1772 & RS232 chip...

A stock ST pulls around 1.8amps I think, a benchtop psu may help there... really just power the thing up see what happens, "finger on chips" make sure nothing is getting burning hot..

Assuming it doesn't boot, first thing is to check all the clocks, 32MHz into shifter, 16MHz to MMU, MMU outputs 8MHz to GLUE, GLUE outputs 4MHz...

Checking /AS on the CPU will show if the CPU is even trying to do something or not...

[PhilC]

Ok, may give it a go over the weekend if I get chance.

whats the best circuit diagram to follow for the main STF stuff, I know you've changed some of the RGB bits etc but should have the same type signals in, presuming it gets that far of course :-)

[exxos]

whats the best circuit diagram to follow for the main STF stuff, I know you've changed some of the RGB bits etc but should have the same type signals in, presuming it gets that far of course :-)

https://www.exxosforum.co.uk/forum/viewt ... f=19&t=199

I've not done any massive changes really, its almost the same as the MEGA ST circuit.

[PhilC]

Ok, you know I've had a bit of practice with that lol.

Will let you know when I get a chance to get everything and the fire extinguisher set up.

Probably have to rely on someone else to do a video if needed but will take photos of anything interesting.

[PhilC]

Ok so a brief update.

I've plugged the board into my bench power supply, just the two five volt and two 0 volt rails and recorded a current use of 440ma.

None of the components are even warm to touch after being on for 5 mins but no video as yet.

I presume the lack of video is due to a lack of 12v going to the board?

Probably won't get much more done tonight.

A quick question, too tired to look, are both 5v rails interconnected? Just checking how I should link the bench power supply up. It's a 2 channel psu.

[troed]

I've plugged the board into my bench power supply, just the two five volt and two 0 volt rails and recorded a current use of 440ma.

None of the components are even warm to touch after being on for 5 mins but no video as yet.

I presume the lack of video is due to a lack of 12v going to the board?

whoa, we have first boot!

regardless of not successful, that's major :D

with that current draw I'm not sure much is running. You'd need an LA or an oscilloscope to start looking at signals.

(What video out are you using? An ubeswitch uses 12V but otherwise you should be good without it)

[PhilC]

I've got a ubeswitch connected.

Btw, no ram connected yet either, so likely the cpu is halted. I just wanted to plug things in with the least possible to make sure there were no major unexpected events :D

I have a scope here, so can start looking at signals probably tomorrow night.

[troed]

I've got a ubeswitch connected.

Ok :) Then you need to manually patch it if you don't have a 12V source (I think ube wrote how in one of these threads). And without ram maybe that current usage would actually be correct.