Jump to content
IGNORED

Atari 800 Ram Issues


Fierodoug5

Recommended Posts

Just got a Atari 800. Has a 10k OS in slot one and three 16k rams cards. In basic doing ?FRE(0) it reports only 29,710

Testing one ram card at a time in slot closest to OS card, each card reports 13,326 as normal.

Tried swapping the cards to all different locations, yet it will show only 29,710

Any ideas what might be going on here??

Link to comment
Share on other sites

Try cleaning all 3 RAM slots with a good electrical contact cleaner - there are various ways to do this without damaging the pins. I like to spray cleaner into the slot, wipe some on the edge connectors of the cards, then insert and remove the cards several times vigorously to spread the cleaner and wipe away any surface dirt of corrosion. Do this with the power disconnected of course. Then let things air dry thoroughly, reinstall the cards and see if that resolves the issue.

Link to comment
Share on other sites

2 hours ago, Fierodoug5 said:

Just got a Atari 800. Has a 10k OS in slot one and three 16k rams cards. In basic doing ?FRE(0) it reports only 29,710

Testing one ram card at a time in slot closest to OS card, each card reports 13,326 as normal.

Tried swapping the cards to all different locations, yet it will show only 29,710

Any ideas what might be going on here??

I don't have an answer.  Sorry.   However, coincidentally this happened to my 800 only last night.  I swapped the cards around a few times and eventually it started to work and report the correct amount of RAM in BASIC but the machine is not stable. 

 

Any two boards in the 1st and 2nd RAM slots it seems OK but if I add the third board to the final slot the 800 does not remain stable for long.  

 

I've had the 800 since 1980.

 

-SteveS

  • Like 1
Link to comment
Share on other sites

1 hour ago, Fierodoug5 said:

Yeah its wierd, mine seems pretty stable. Been running a demo for over a hour now. Even tried some games that require 48k and they ran fine. Still reports 29,710 in basic...weird.

That is weird.

 

I reseated all the chips of all three memory boards. 

 

I've been running Archimedes Spiral (compiled FastBasic version) for 20 minutes now.  Seems OK.

 

I hope so because I don't have the skills to repair anything.

 

-SteveS

  • Like 1
Link to comment
Share on other sites

Could this be something to do with the BASIC cartridge or cartridge slot itself??

 

It sounds as if this BASIC cartridge has been modded to/is behaving like a 16K cartridge?

 

This was sometimes done to for example include MonkeyWrench (originally a Right Cartridge BASIC enhancement) and BASIC into one 16K Left cartridge...

 

Any sign that the cartridge has been modded?

 

It would be interesting to run the following to see if there is data in memory between $8000-$9FFF (Right Cartridge memory bank) when BASIC is inserted:

 

10 FOR F=32768 TO 40959: PRINT CHR$(PEEK(F));: NEXT F

 

This should fill the screen with 'random' characters if there is data/code in this memory range.

 

What does FRE(0) report with a disk-based BASIC such as Turbo-Basic XL?

Edited by drpeter
  • Like 3
Link to comment
Share on other sites

Can't run turbo basic XL on an 800, it needs an XL :) (it uses RAM under the OS).

 

I like @drpeter's idea to print the conents of the 8K RAM normally under BASIC. It should all be 0's (or heart characters) if its empty RAM. If not, you may have a modified 16K Atari BASIC cart.

 

Just to be sure, maybe unscrew the 1 screw in your BASIC cart to take the metal cover off, and post a picture of the inside?

Link to comment
Share on other sites

2 hours ago, Nezgar said:

Can't run turbo basic XL on an 800, it needs an XL :) (it uses RAM under the OS).

 

Turbo BASIC XL has a slightly cut-down version which runs on 400/800-  Frost BASIC 1.4, which was later named TURBO-BASIC 1.4

Edited by drpeter
mistype
  • Like 1
Link to comment
Share on other sites

Yeah, it was that basic cart. I found another basic cart and it reports 39,700

When I have time I will open it up and see what is going on with it

Oddly Turbo Basic 1.4 on floppy only reports 22,900 or something like that.

Either way, I'm just glad my new to me Atari 800 now fully works and I love it. Still want to get a 810 someday, but I have a pile of non-working 1050's here, so I repaired one and am using that for now. My other 8bit setup is a 800xl, but there is something extra special about the 800. Mines a bit yellow, but retrobrite will help that once the warmer months hit NJ.

Thanx for all the help everyone!

Doug

Link to comment
Share on other sites

5 hours ago, Fierodoug5 said:

Mines a bit yellow, but retrobrite will help that once the warmer months hit NJ.

Thanx for all the help everyone!

Doug

Have you thought of trying light bright? 

I was sceptical but did my 400 last summer and it worked great.

I had previously ruined a 400 case with retrobright so didn't want to do that again

Link to comment
Share on other sites

6 hours ago, Fierodoug5 said:

Yeah, it was that basic cart. I found another basic cart and it reports 39,700

When I have time I will open it up and see what is going on with it

Cool! Most curious about it now. :)

6 hours ago, Fierodoug5 said:

I have a pile of non-working 1050's here, so I repaired one and am using that for now.

Once you have a working one, things are much easler to diagnose the non-working ones. the main IC's are always socketed on the motherboard for easy swapping (just ensure that the 2797/2793 controller remains with the original PCB if at all possible). Mechs are also easy to swap.

Link to comment
Share on other sites

10 hours ago, Fierodoug5 said:

Oddly Turbo Basic 1.4 on floppy only reports 22,900 or something like that.

That's correct for Turbo Basic 1.4 on a 48K system- because it doesn't 'hide' much of its code in the RAM 'behind' the XL OS like Turbo Basic XL can on 64K systems.

 

Consequently, along with having loaded DOS, it uses ~24K of the 48K of 'exposed' RAM.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...