600XL Upgrade and Problem

[jnharmon]

I picked up an NTSC 600XL off eBay a few weeks ago and have finished stage one of the upgrades, including replacing the channel 2-3 selector switch with a 5 pin DIN video port and UAV, and upgrading it to 64K.  The next step will be installing an Ultimate 1M board.

 

Mostly things have been successful.  The one problem I am seeing is that when I turn it off, if I don't wait around 15 seconds before turning it back on the computer will lock and not reboot.  If I power cycle it quickly, the old program will remain at least partially in memory (at least screen RAM) and I can see the previous screen on the display.  When cleanly booted, everything seems to work properly.

 

For the RAM upgrade I used 41464-10 DRAM chips.

 

Any ideas what could cause this issue and what can be done to correct it?

 

 

Edited August 11, 2019 by jnharmon

[_The Doctor__]

Yes, your new memory retains the data as it's leak down is slower because of better silicon, this is normal. this also means the atari can handle slight power issues better. Just wait the 11 to 15 seconds and it'll be fine..

[flashjazzcat]

When you install U1MB, this will be less of an issue since the firmware can trigger an OS coldstart without aid of the power button.

[jnharmon]

13 minutes ago, flashjazzcat said:

When you install U1MB, this will be less of an issue since the firmware can trigger an OS coldstart without aid of the power button.

 

44 minutes ago, _The Doctor__ said:

Yes, your new memory retains the data as it's leak down is slower because of better silicon, this is normal. this also means the atari can handle slight power issues better. Just wait the 11 to 15 seconds and it'll be fine..

Thanks for the info gentlemen.

 

[SS]

On the plus side, the hole that you drilled for your monitor port looks super clean! 

[flashjazzcat]

6 minutes ago, SS said:

On the plus side, the hole that you drilled for your monitor port looks super clean

Seconded... I wonder if it was done with a hole cutter? It looks perfect.

[jnharmon]

59 minutes ago, SS said:

On the plus side, the hole that you drilled for your monitor port looks super clean! 

 

52 minutes ago, flashjazzcat said:

Seconded... I wonder if it was done with a hole cutter? It looks perfect.

 

Thanks.

 

I first traced a circle on the plastic and then cut the plastic by hand using a Dremel carbine cutter bit to get close to but not quite touching the traced line.  After that I used a sanding drum just a bit smaller than the hole to go up to the cut line.  The hole is a bit larger than the power hole as it needed to be to encapsulate the 2-3 switch cutout rectangle.  Not perfect but good enough.

[flashjazzcat]

2 minutes ago, jnharmon said:

I first traced a circle on the plastic and then cut the plastic by hand using a Dremel carbine cutter bit to get close to but not quite touching the traced line.  After that I used a sanding drum just a bit smaller than the hole to go up to the cut line.  The hole is a bit larger than the power hole as it needed to be to encapsulate the 2-3 switch cutout rectangle.  Not perfect but good enough.

That's almost identical to my method, as it happens. Great job.

 

EDIT: Acetone carefully applied to the inner edge using a q-tip makes for a nice authentic finish on the cut surface.

 

Edited August 11, 2019 by flashjazzcat

[+mytek]

Your hole for the added DIN jack came out perfect ? .  I used what's called a Uni-Bit (stepped drill) for the holes in my 600XL project. But I first started with a template inscribed on some green painters tape, then a drill, then some filing to get a reasonably centered hole, and finished up with the Uni-Bit to get to the final desired hole size. And yes a tiny bit of acetone was used to smooth the edges.

 

I also experienced the need for an extended power-down to clear the memory after doing the 64K upgrade. Just par for the course.

 

 

[+slx]

Same for Antonia which also needs quite some time to lose memory. Made me realize how often I use(d) OFF-ON to reset...

[shoestring]

I don't have this problem with my Antonia. But I have to wait at least 3-5 seconds for the 65XE which now has TMS branded DRAM after a repair.

 

My previous Apple IIe enhanced needed 20 seconds, sometimes 30 or it boots to junk. My current one doesn't.  In any case, the user guide even states that you should wait half a minute in between power cycling.

 

 

 

 

Edited August 13, 2019 by shoestring

[SS]

My ANTONIA needs a good 5 seconds for its RAM to clear itself. 

[jnharmon]

Out of curiosity, I swapped the two IN41464P-10 RAM chips I used with two NEC D41464C-12 chips and the problem vanished.  I can now turn it off and right back on and get a good cold boot each time.

[Rybags]

120 ns vs 100 ns so maybe older technology which erases quicker.

 

In theory you'd only need one since it's only the "magic number" in page 3 that need to be unsettled to make the Atari properly coldstart.  Just a single bit change in any of them is sufficient for that.