Timex 2048 only 16k

landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Timex 2048 only 16k

Post by landex »

Hi
I'm new here.
I bought a Timex 2048 from Portugal, and I realized that something was wrong. I type:
PRINT PEEK 23733

Output was: 127.
I load jetpac and work fine. Then I try to load a 48k games and it doesn't work.
Can it be a memory chip?
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1024MAK
Posts: 4192
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Timex 2048 only 16k

Post by 1024MAK »

Hello,

What does PRINT PEEK 23732 + PEEK 23733 * 256 return?

Here’s a 48K ZX Spectrum quick ‘n simple RAM test. I’ve not tried it on a Timex 2048.

Code: Select all

1 CLEAR 24999
2 FOR a=25000 TO 65535 STEP 250
3 PRINT AT 0,0;a: POKE a,0: LET d=PEEK a: IF d<>0 THEN GO SUB 8
4 POKE a,255: LET d=PEEK a: IF d<>255 THEN GO SUB 8
5 NEXT a
6 PRINT “done”: STOP
8 PRINT “error at “;a;” “;d
9 RETURN
RAM test, test one address only looking for a bit error. Again written for a ZX Spectrum. Not tested on a Timex 2048.
Use an address reported as faulty from the above program.

Code: Select all

1 CLEAR 25999
2 PRINT “Enter address to test”
3 INPUT a
4 PRINT “Address ”;a
5 FOR c=1 TO 4
6 READ t
7 POKE a,t: LET d=PEEK a
8 PRINT “Value written ”;t;“ value read ”;d
9 NEXT c
10 DATA 0,85,170,255
Mark
landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Re: Timex 2048 only 16k

Post by landex »

PRINT PEEK 23732 + PEEK 23733 * 256

Output:
32767
landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Re: Timex 2048 only 16k

Post by landex »

1024MAK wrote: Sat May 28, 2022 7:50 pm Hello,

What does PRINT PEEK 23732 + PEEK 23733 * 256 return?

Here’s a 48K ZX Spectrum quick ‘n simple RAM test. I’ve not tried it on a Timex 2048.

Code: Select all

1 CLEAR 24999
2 FOR a=25000 TO 65535 STEP 250
3 PRINT AT 0,0;a: POKE a,0: LET d=PEEK a: IF d<>0 THEN GO SUB 8
4 POKE a,255: LET d=PEEK a: IF d<>255 THEN GO SUB 8
5 NEXT a
6 PRINT “done”: STOP
8 PRINT “error at “;a;” “;d
9 RETURN
It gets errors after address 33000 .
sP1d3r
Posts: 61
Joined: Mon May 16, 2022 9:20 am

Re: Timex 2048 only 16k

Post by sP1d3r »

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.
landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Re: Timex 2048 only 16k

Post by landex »

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.
Sp1d3r, it's very interesting what you said. My has four 4164 chips. Some one made a mistake. Só don't you think?
Attachments
IMG_20220528_190251.jpg
landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Re: Timex 2048 only 16k

Post by landex »

can I use an mk4116n-2 to substitute the 4416 chips?
sP1d3r
Posts: 61
Joined: Mon May 16, 2022 9:20 am

Re: Timex 2048 only 16k

Post by sP1d3r »

landex wrote: Sun May 29, 2022 6:12 pm can I use an mk4116n-2 to substitute the 4416 chips?
4116 DRAM chips are 1-bit but 4416 chips are 4-bit, so no because they're not compatible.

Can you post a picture of the whole motherboard?
sP1d3r
Posts: 61
Joined: Mon May 16, 2022 9:20 am

Re: Timex 2048 only 16k

Post by sP1d3r »

Here's a pic of my TC2048, it has 2 4416 and 2 41464 chips but this is possibly a different version because it looks like yours has a different mix of DRAM chips.
WP_20181112_003.jpg
Last edited by sP1d3r on Wed Jun 29, 2022 10:26 am, edited 1 time in total.
landex
Posts: 21
Joined: Sat May 28, 2022 1:16 am

Re: Timex 2048 only 16k

Post by landex »

My has more 2x4164 chips, Here
timex2048-2.jpg
timex2048-1.jpg
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