Timex 2048 only 16k

sP1d3r
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Re: Timex 2048 only 16k

Post by sP1d3r »

landex wrote: Sun May 29, 2022 8:43 pm My has more 2x4164 chips
From what I understand, something like a Retroleum Smart card in diagnostic mode would be able to check the ram chips, I can't check this myself because my TC2048 doesn't boot up for some reason.

Unless you can desolder the chips and test them, relying upon the compatibility with a standard Spectrum rom to run one of the Spectrum diagnostic roms in a expansion would be your best bet.

My TC may have a faulty rom, it uses a 27128 not a 23 series. I've tested my ram chips and they work.
landex
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Re: Timex 2048 only 16k

Post by landex »

sP1d3r wrote: Sun May 29, 2022 11:36 pm
From what I understand, something like a Retroleum Smart card in diagnostic mode would be able to check the ram chips,
I don't know if the Retroleum Smart card would help because I have a dandanator and it doesn't work in tc2048. It should, shouldn't? at least the 16k games.
sP1d3r
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Re: Timex 2048 only 16k

Post by sP1d3r »

landex wrote: Mon May 30, 2022 1:01 am
I don't know if the Retroleum Smart card would help because I have a dandanator and it doesn't work in tc2048. It should, shouldn't? at least the 16k games.
I know that there's very little difference between a TC2048 rom and the Spectrum rom, see;

https://timex.comboios.info/tc2048.html

so perhaps it should.
landex
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Re: Timex 2048 only 16k

Post by landex »

Thanks guys! At least I have an 16k TC2048 :lol:

By the way, what s happen if I remove all hi-mem? Isn't the same as 16k?
sP1d3r
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Re: Timex 2048 only 16k

Post by sP1d3r »

landex wrote: Mon May 30, 2022 6:43 pm
By the way, what s happen if I remove all hi-mem? Isn't the same as 16k?
Which chips are which?
landex
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Re: Timex 2048 only 16k

Post by landex »

sP1d3r wrote: Mon May 30, 2022 10:10 pm
landex wrote: Mon May 30, 2022 6:43 pm
By the way, what s happen if I remove all hi-mem? Isn't the same as 16k?
Which chips are which?
U8, U9, U10, U11
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1024MAK
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Re: Timex 2048 only 16k

Post by 1024MAK »

sP1d3r wrote: Sun May 29, 2022 3:44 pm
landex wrote: Sat May 28, 2022 4:23 pm Can it be a memory chip?
A Timex TC2048 has two different types of memory chip, two 4416 and two 4164 chips, IIRC.
The thing to do would be to desolder and test the chips with a DRAM tester, this would eliminate the memory chips as the source of the problem.
I believe there were at least two different boards made, each using different DRAM chip arrangements.
landex wrote: Mon May 30, 2022 1:01 am
sP1d3r wrote: Sun May 29, 2022 11:36 pm
From what I understand, something like a Retroleum Smart card in diagnostic mode would be able to check the ram chips,
I don't know if the Retroleum Smart card would help because I have a dandanator and it doesn't work in tc2048. It should, shouldn't? at least the 16k games.
Did you try the second program I posted? What were the results?
If it’s working enough for BASIC to run, it’s possible to do plenty of useful tests just using BASIC.

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landex
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Re: Timex 2048 only 16k

Post by landex »

Mark, I put the 2nd program and it's strange. The output is the same. Example:
Memory 44000. Output always 3.
Also 35000, output 3 all.
Adresse 12, all 95.
Adresse 7800, all 10.

What can it be now?
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Paul
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Re: Timex 2048 only 16k

Post by Paul »

Last two addresses are in ROM.
Try 32760 to 32780
In theory, there is no difference between theory and practice. But, in practice, there is.
landex
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Re: Timex 2048 only 16k

Post by landex »

Paul wrote: Tue May 31, 2022 5:42 pm Last two addresses are in ROM.
Try 32760 to 32780
Hi Paul.
I try it
From 32760 to 32767 it's everything ok. But from 32768 to32780 it adds 1 value at 0, 85 and 170. The 255 it's in every memory fine.

32767 it's the last memory of the 16kb, isn't?
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