Posted By
Alfh
on 2018-11-22
09:44:12
|  C16 Basic bytes freo. Freo?!
On my C16 startup screen reads "..BYTES FREO". Also when i type screen full of "H" letter, the third last character is "X". Some letters seems to work ok.
Most of the games did load from SD2IEC and sounds and joystic works. Some games just resulted scrambled screen.
So can you gurus make a guess which chip is faulty?
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Posted By
Csabo
on 2018-11-22
09:56:50
| Re: C16 Basic bytes freo. Freo?!
The difference between "E" and "O" is only two extra bits set. My guess is that the RAM is faulty.
If you don't mind typing a bit, that can be easily checked with a little program: forum/35558/-/memcheck
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Posted By
Alfh
on 2018-11-22
11:39:57
| Re: C16 Basic bytes freo. Freo?!
I typed the code and got green border and "41f8eeeeeeee..". Then i tried to type it again and got just green border.
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Posted By
Csabo
on 2018-11-22
16:12:52
| Re: C16 Basic bytes freo. Freo?!
Was the "eeeeeeee" part actually "@@@@@@@@"? If so, that's normal. However, stopping at any point before the end (which is $FD00) is not, that would indicate that there is indeed a problem with the RAM. Yeah, unfortunately you can't restart this little program, but you could save it before running it. That way, you can reload it many times to see if it consistently stops at the same place. You would save it with S"memcheck" 8 600 684.
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Posted By
Alfh
on 2018-11-23
05:47:39
| Re: C16 Basic bytes freo. Freo?!
Yes those were probably "@@"'. I don't have spare 4416 chips so is it okay to swap 41464 instead without 64k mod? I don't want to cut any traces on almost unused mobo (this c16 was new old stock and never used).
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Posted By
Alfh
on 2018-11-23
11:34:01
| Re: C16 Basic bytes freo. Freo?!
I did go ahead and tested 41464 ram chips and C16 boots as it was before. So still "12277 BYTES FREO". Well at least now I have socketed rams.
Could it be U4 318004-04 kernal/char rom? At least those are cheap in ebay.
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Posted By
Csabo
on 2018-11-23
20:34:05
| Re: C16 Basic bytes freo. Freo?!
By the way, one other thing you could try is check the ROM. Type MONITOR, Return/Enter, M80F6, Return/Enter. This should print the portion of the ROM from where the "BYTES FREE" text is copied onto the screen.
Let me know what it says 
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Posted By
Doug
on 2018-11-24
10:22:36
| Re: C16 Basic bytes freo. Freo?!
That has to be the internal RAM buffer in the TED.
A dump from $c00 would prove it.
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Posted By
bubis
on 2018-11-24
15:57:05
| Re: C16 Basic bytes freo. Freo?!
It seems to me as well that TED's internal memory has some issues. Some bits seems to have a fixed value in there.
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