Jeff
01-29-2007, 1:32 AM
James;
No good on the striping issue. I just posted a TECH request for my
Galaga problems.
Jeff
On Dec 27 2006, 9:05 pm, jrok <jrok...@san.rr.com> wrote:
> In article Cyrus Cosmo says...
>
>
>
> >Hi - I did swap out my 2147's with 2 x48's and I still seem to have the
> >striping problem in my bugs. The blues and reds seem to be ok so the
> >blue wings and red wings on the bugs seem solid but the bodies have
> >lines and the big green bugs have lines on wings and bodies.
>
> >I've swapped all the custom chips on the video PCB with known working
> >ones and that didn't change anything.
>
> >Any suggestions?Striping down the sprites, when the RAM is known to be good, is very
> likely to be one of the 74LS365's at location 6A or 5A. One's for odd
> sprite lines the other is for even lines. It could be the 74LS298 at
> 5B, but I personally have seen the buffers be a point of failure more
> often than the Mux. That might just be my bad luck ;)
>
> Use a logic probe on the outputs to see if one of the bits for the RAM is
> stuck high or low. If one of the bits on the output of the 365 at 5A
> (pin 5,7,13,11) is pulsing and it's opposite number at 6A (pin 5,3,9,11)
> isn't pulsing that should be the one. Without a probe you should be able
> to figure it out by pulling the 2148 RAM from 6B, then check to see if
> all sprite lines are corrupt. If all the sprite lines now look bad then
> it's the the buffer at 5A. If half the sprite lines look correct and
> the others look bad, it's 6A.
>
> It also wouldn't hurt just to check there are no track breaks between
> the outputs of the 365 and the 2148's, and the 74LS298 at 5B.
>
> OH ! One final thing I almost missed, check the resistor pack RM5, I think
> that's the right one, isn't damaged or snapped off.
>
> - James
>
> --
> ------------------------------
> JrokLandhttp://www.jrok.com
> ------------------------------
No good on the striping issue. I just posted a TECH request for my
Galaga problems.
Jeff
On Dec 27 2006, 9:05 pm, jrok <jrok...@san.rr.com> wrote:
> In article Cyrus Cosmo says...
>
>
>
> >Hi - I did swap out my 2147's with 2 x48's and I still seem to have the
> >striping problem in my bugs. The blues and reds seem to be ok so the
> >blue wings and red wings on the bugs seem solid but the bodies have
> >lines and the big green bugs have lines on wings and bodies.
>
> >I've swapped all the custom chips on the video PCB with known working
> >ones and that didn't change anything.
>
> >Any suggestions?Striping down the sprites, when the RAM is known to be good, is very
> likely to be one of the 74LS365's at location 6A or 5A. One's for odd
> sprite lines the other is for even lines. It could be the 74LS298 at
> 5B, but I personally have seen the buffers be a point of failure more
> often than the Mux. That might just be my bad luck ;)
>
> Use a logic probe on the outputs to see if one of the bits for the RAM is
> stuck high or low. If one of the bits on the output of the 365 at 5A
> (pin 5,7,13,11) is pulsing and it's opposite number at 6A (pin 5,3,9,11)
> isn't pulsing that should be the one. Without a probe you should be able
> to figure it out by pulling the 2148 RAM from 6B, then check to see if
> all sprite lines are corrupt. If all the sprite lines now look bad then
> it's the the buffer at 5A. If half the sprite lines look correct and
> the others look bad, it's 6A.
>
> It also wouldn't hurt just to check there are no track breaks between
> the outputs of the 365 and the 2148's, and the 74LS298 at 5B.
>
> OH ! One final thing I almost missed, check the resistor pack RM5, I think
> that's the right one, isn't damaged or snapped off.
>
> - James
>
> --
> ------------------------------
> JrokLandhttp://www.jrok.com
> ------------------------------