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Re: kodak80 H4 build (x2)

Posted: 30 Nov 2019 10:41
by Icky
@kodak80 , I think @exxos may be right but could be the angle of the pic. I had a very small hairline solder bridge short on my SN74LVC1G11DBVR on the bottom right :)

Re: kodak80 H4 build (x2)

Posted: 30 Nov 2019 11:41
by kodak80
It looks okay to me.
D4CCD9BD-002D-428D-93A9-06A9E047C092.jpeg

Re: kodak80 H4 build (x2)

Posted: 30 Nov 2019 12:38
by Icky
kodak80 wrote: 30 Nov 2019 11:41 It looks okay to me.
Must of been the angle of the other pic :)

Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 01:45
by kodak80
Okay, first board is built apart from external connectors. Have a Falcon 4mb RAM board to fit and also a 4mb SIMM so I can test both options (not at the same time though).

Still need to run through the fixes as well.
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Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 02:09
by exxos
Looking good :thumbup:

Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 02:27
by kodak80
After taking the photos I found that the 74LS02 IC had a bent pin not in the socket so this is now fixed.

I have socketed the 32mhz OSC for now using 4 individual female pins which allows me the flexibility of using a cheap 32.0mhz OSC for initial testing and can change over to the proper OSC once I know the system boots. With this setup, the OSC just misses the PSU metal plate so will need to cover the OSC when powered on. Would it cause issues if the OSC metal case touches the PSU metal plate and is grounded?

I am thinking that I will stick with the 13 pin din video port. @exxos and @Icky Any benefits on using the VGA port instead? I guess it will be hard to swap these once one is soldered in.

Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 02:35
by kodak80
https://www.exxosforum.co.uk/forum/posti ... 78&p=29092
@exxos and @Icky Just wondering the best option for the BGACK PULLUP fix if the expansion port sockets are not installed?

Edit: here is the fix applied to the PLCC CPU socket along with the DTACK fix.
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Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 03:37
by kodak80
Okay, fitted the 13 pin din video connector (not yet soldered in but fairly sure the pins are all connected to the board) along with the Falcon 4mb RAM card and powered on......

White screen, same as @derkom. I have a known working Exxos 1.02/1.04 TOS ROM from one of my Alpha boards in place so it is not this that is the issue.
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Blitter jumpers are connected as I do not have a blitter in the socket yet. All jumpers as per @Icky guide.

No floppy access attempt. Do not have one connected at the moment though.

Also tried with a 4mb SIMM instead of the Falcon RAM card but the boot up was the same white screen.

At least there was no magic smoke so not unhappy with where I am at the moment and may have to wait for more skilled builders to get to booting their boards. :D

Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 07:45
by PhilC
Well done for getting this far so quickly.

Sounds like itll be an easy fix once someone finds it.

Re: kodak80 H4 build (x2)

Posted: 01 Dec 2019 08:02
by kodak80
Thanks @PhilC I did seem to power through this one compared to the Alpha board.

Still scary turning on the power though.