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Re: Forgottenmyname - Progress - Part 2

Posted: Sun Jun 16, 2019 6:37 pm
by Icky
:cheer: - There is life

Re: Forgottenmyname - Progress - Part 2

Posted: Sun Jun 16, 2019 6:40 pm
by PhilC
Yeah, just replacing the rom socket right now

Re: Forgottenmyname - Progress - Part 2

Posted: Sun Jun 16, 2019 7:15 pm
by PhilC
That's the rom socket replaced and now what I get it a lot of repeating patterns on /OE on the rom but still nothing on the serial.

Last time I got the serial to work it came up with a ram fault, so I'm just wondering if the repeating patterns on the /OE and other lines is the repeating message you get with the diag cart in and bad memory.

So I'll swap the SMt ram over, which wont take long and then see what happens.

Re: Forgottenmyname - Progress - Part 2

Posted: Sun Jun 16, 2019 9:04 pm
by exxos
How you end up with V&H swapped ? I thought it was working originally ? Wasn't it you who put the ROM socket in wrong originally as well :)

RAM fault may well be a bad socket or solder joint on the RAM headers or MMU, or buffers..

Re: Forgottenmyname - Progress - Part 2

Posted: Sun Jun 16, 2019 9:20 pm
by PhilC
It was me originally that got the rom wrong but this time it was dodgy pins I wanted to rule out, good job I did.

Got v and h mixed up as I was soldering it all up without the unf*ck board, an idea I stole from Icky.

Story is far is cpu not halted but screen at 60hz still but will check the connections this week.

Btw, this Alpha board has never really worked correctly but I'll get there eventually.

Re: Forgottenmyname - Progress - Part 2

Posted: Mon Jun 17, 2019 6:13 am
by Icky
PhilC wrote:
Sun Jun 16, 2019 9:20 pm
Got v and h mixed up as I was soldering it all up without the unf*ck board, an idea I stole from Icky.
Careful with those ideas, they turn into projects very quickly.

Re: Forgottenmyname - Progress - Part 2

Posted: Fri Jun 28, 2019 6:59 pm
by PhilC
Definitely life in the old girl yet.

Screen working, rom working, cart port working, memory NOT SO MUCH.

I've tried a couple of MMUs but still get this Diagrom failure list for the full memory bank, even using falcon ram board and a marpet with 4mb.

Not sure what it is yet, maybe someone can help shed some light on it whilst I get the scope out:
memory failure.PNG
memory failure.PNG (13.82 KiB) Viewed 438 times

Re: Forgottenmyname - Progress - Part 2

Posted: Fri Jun 28, 2019 7:24 pm
by exxos
Seems every RAM address line is failing, its just reading all 1's off the bus like nothing is driving the databus..

Are the buffers the right ones ? in the right way etc ?

Re: Forgottenmyname - Progress - Part 2

Posted: Fri Jun 28, 2019 7:28 pm
by PhilC
exxos wrote:
Fri Jun 28, 2019 7:24 pm
Seems every RAM address line is failing, its just reading all 1's off the bus like nothing is driving the databus..

Are the buffers the right ones ? in the right way etc ?
yes they are buti'm wondering if one has died. typical I soldered these direct to the board

Re: Forgottenmyname - Progress - Part 2

Posted: Fri Jun 28, 2019 7:41 pm
by exxos
PhilC wrote:
Fri Jun 28, 2019 7:28 pm
yes they are buti'm wondering if one has died. typical I soldered these direct to the board
Saying that, both would have had to die to block the whole databus out..

Have you metered the enable lines from the MMU to the buffers ? pins 30,9,25 on the MMU..