[Techtoolslist] Poss. dumb 9010 query

[Martin White]

Found me "BTS 08" problem, a broken track underneath the 245 at B3.

Now onto a decode error!

On Wednesday 06 July 2005 12:00, Martin White wrote:

> Program ram (a single 6116 on the SCPU board) can't be tested at all. It

> simply can't talk to it properly, nor the roms (so it would seem anyway -

> wander if that's anything to do with the CTC?). It comes up with BTS FF

> error for any address in program ram - a single 6116. This is not a fault

> though, it's just the way it is. It does it on all 15 boardsets i'm working

> on, even the ones where the game works fine and there are just issues with

> the SSIO board!

>

> The staging ram (2 x 2114 on the vid gen board) have the BTS 08 error,

> however, the problem doesn't lie with anything on the vid gen board since

> you can disconnect that board completely and still get the BTS 08 error

> when you try to do the test on the background ram.

>

> I haven't tried removing all the roms to see if they're fouling the busses

> at all, but they shouldn't be since they're known good roms. Could be

> sockets i guess?

>

> So you see, i'm pretty sure i'm looking at a buffer / interface problem,

> just wanting to confirm if it's the address lines or the data lines for the

> particular Fluke error message. I'm pretty sure it's the data lines.

>

> However, i'm not seeing any bit tied high or low, so maybe i'll just

> replace the 245 anyway for the fun of it, and maybe the cpu socket, and i

> guess i can always try removing the pull-up resistor pack on the data lines

> and see if the problem goes away before putting them back of course!

>

> Cheers all...

>

> Martin.

>

> On Wednesday 06 July 2005 01:50, John Robertson wrote:

> > How about trying to test RAM in a different IC?

> >

> > If you have three banks of RAM, try testing each bank to see if you

> > get the problem in one bank or all. One bank is obviously the sick

> > RAM chip, ALL banks would be some interface or timing issue, but if

> > all banks show the same error then pretty safe to be an interface IC

> > issue.

> >

> > John :-#)#

> >

> > At 1:39 AM +0100 7/6/05, Martin White wrote:

> > >Sorry, but i do get rather confused with this thing from time to time

> > > :o)

> > >

> > >I'm getting a "R/W Error @ F800 BTS 08" when trying to test the ram on

> > > one of these MCR boards. Am i right in saying that i need to be

> > > tracking down a problem on the data bus, bit 4, bit 3 if you prefer

> > > your numbers to be 0 based (1000 = 8, therefore, that's bit 0, 1, 2,

> > > then 3 or 1, 2, 3, then 4).

> > >

> > >And if it were a decode error then that would be the address bus?

> > >

> > >I'm assuming all is well with chip selects and r/w signals since it's

> > > only complaining about bit 08 and not FF?

> > >

> > >As an aside, i burnt a set of home burnt roms but the 9010 still can't

> > > read the things reliably in the MCR sets. It doesn't seem to like

> > > anything that's in close relation to the CTC i don't think. It's happy

> > > enough troubleshooting the video staging ram and the background ram,

> > > just not the program ram or rom :(

> > >

> > >I'm using a normal Z80 pod with a Z80A processor in it. I'm guessing

> > > from reading previous posts that there would be no benefit in trying to

> > > blag or borrow a Z80AA since someone else was saying that couldn't cope

> > > with MCR hardware either.

> > >

> > >Martin.

> >

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