Icky - Progress

[exxos]

I've checked the acia and mfp circuit and looks good.. Just have to check ram with diagrom next I think..

[Icky]

I've checked the acia and mfp circuit and looks good.. Just have to check ram with diagrom next I think..

I have just been working through your states and things are a little odd.

Code: Select all

8MHZ = 125NS - My board is 8MHz = 125ns

VPA GOES HI & LO WITH AS - My board AS has signal but VPA is sat at always at high 5V

VPA GOES LOW THEN VMA GOES LOW ~200NS LATER (BOTH HIGH ABOUT SAME TIME) - My board VMA is sat high 5V

6850 CS GOES HI 1,000ns AFTER VPA, FOR ABOUT 600ns HI.  (6850 CS GOES LOW (DISABLE) WHEN VPA GOES HI SAME TIME) - My board 6850 CS is Low always on 0V

Scope image of /AS below:

DS1Z_QuickPrint6.png (52.13 KiB) Viewed 3272 times

[exxos]

/as on its own doesn't really mean anything.. VPA,VMA,E,650CS Are the important ones.. But need to check each vs vpa so need 2 channels to check..

[exxos]

Its pretty much, after /AS goes low..

VPA GOES LOW, VMA GOES LOW, E GOES HIGH..
VPA GOES HI, VMA GOES HI, E GOES LOW..

I would assume its OK if they all switching anyway.. But check E and CS on the ACIA chips themselves..

[PhilC]

Hi All, 1 step forward today, my GLUE is now changing screen frequency, so my TV has an orange screeen now, not yellow, LOL. Seem to be getting over 70hz instead of 60.

So I wondered if Icky or exxos know which 3 pins to swap and I'll see if I can once again join the fun with the diagnostics

[exxos]

So I wondered if Icky or exxos know which 3 pins to swap and I'll see if I can once again join the fun with the diagnostics

Theres 3 pins which are the same, they rest are wrong.. This post show the swapping needed, but Icky did a new cable to fit...

https://www.exxosforum.co.uk/forum/viewt ... =19&t=1211

[PhilC]

Yeah I think I'll modify my cable too as the rest of my Atari stuff is UBE

[exxos]

Yeah I think I'll modify my cable too as the rest of my Atari stuff is UBE

Don't know if it be easier to remove the socket and hardwire back that based on my pcb than mod the cable ?

[Icky]

Yeah I think I'll modify my cable too as the rest of my Atari stuff is UBE

Don't know if it be easier to remove the socket and hardwire back that based on my pcb than mod the cable ?

I was trying different options ie to rewire the socket etc. I gave up as I found that the cable mod on the atari plug side was the simplest as it was only three wires on my cable that needed to be moved around

[Icky]

Its pretty much, after /AS goes low..

VPA GOES LOW, VMA GOES LOW, E GOES HIGH..
VPA GOES HI, VMA GOES HI, E GOES LOW..

I would assume its OK if they all switching anyway.. But check E and CS on the ACIA chips themselves..

I think there might be a problem with CS line (possibly my soldering - I never rule out my soldering as the first issue) as E on ACIA is ok but CS is floating around 200mV on both ACIAs.

Am going to check it out and see if I find anything.