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Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 09:56
by rubber_jonnie
Woo hoo!!

My LS163's just arrived so the 600 should hopefully be back up and running very soon!!

Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 10:52
by stephen_usher
:dualthumbup:

Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 11:46
by rubber_jonnie
And we have video again!!!

IMG20240405113727.jpg

And I've made a slight tweak to the value in the monitor ROM at $7E0 from 65 to 64, and it's shifted over 1 column left now, which is enough.

A value of 63 is too far, and ideally the value would be 63.5, but we know that's not going to happen.

It's close enough for 24 columns to work.

Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 13:29
by stephen_usher
Yay! :-)

Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 14:04
by stephen_usher
So, next is the tape interface... Remove the cap and see what happens. I dare you. :-)

Re: OSI 600D Superboard Build

Posted: 05 Apr 2024 14:18
by rubber_jonnie
stephen_usher wrote: 05 Apr 2024 14:04 So, next is the tape interface... Remove the cap and see what happens. I dare you. :-)
Lol, I already did and it didn't help. I have a concern that my 'scope probe maybe faulty so going to try another. Might just be me being paranoid :)

I also have a test routine that is in the service manual, so going to try that, see what it turns up.

Re: OSI 600D Superboard Build

Posted: 09 Apr 2024 12:58
by rubber_jonnie
I've been doing a bit of 'burn in' with the OSI just to try and flush out any more bad IC's, and so far it's looking good :)

Of interest is the power consumption:

IMG20240409124943.jpg

And that's just for the base machine with 8KB of RAM and not a lot of other stuff. I'm wondering how much extra load the 610 expansion board will add with the extra RAM and FDD interface.

Yep I know the voltage is a bit higher, but well within spec and only set that way so I could check some voltages expected on the cassette circuit. They're low at 5v, and still low at 5.2v, but I'm honestly not sure if it will make much difference to the circuit on account of them being well into the TTL high range even if not the same as the service manual states.

I guess we'll see. Off to set it back to 5v now.

IMG20240409130222.jpg

There you go :)

Re: OSI 600D Superboard Build

Posted: 09 Apr 2024 13:45
by stephen_usher
One and a half amps is quite a lot. I wonder what's burning all that electricity.

Re: OSI 600D Superboard Build

Posted: 09 Apr 2024 13:56
by rubber_jonnie
stephen_usher wrote: 09 Apr 2024 13:45 One and a half amps is quite a lot. I wonder what's burning all that electricity.
I think, and I'd have to go and check, but the specced PSU in the manual is for 6A, which would give headroom for the 610 to be added. That is with just a simple basic program running that prints out all the available characters on screen then starts again.

I'll see if I can get a thermal pic of what's the hottest :)

Re: OSI 600D Superboard Build

Posted: 09 Apr 2024 14:09
by stephen_usher
Actually, thinking about it, 1.5A at 5V is only 7.5 watts. It just seems a lot.