PRYNT, POKU, bad ROM or ULA in TS1000?

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KayBee
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Joined: Mon Feb 13, 2017 5:34 pm

PRYNT, POKU, bad ROM or ULA in TS1000?

Post by KayBee » Thu Sep 19, 2019 6:14 pm

Hi Smart People, I have a couple of TS1000 "new in box." Well A fellow wanted to trade with me for one of them so I unboxed it in order to test it.
When I tap the PRINT key, I get "(PRYNT(" and when I use the POKE key I get "POKU."
Have you folks ever seen this behavior? My first thought was somehow this TS1000 has a foreign ROM, but why the bracket ahead of the keyword? Then I thought perhaps a corrupt ROM, or ULA.

The other "new in box" did not do this, though most of the keys are not working (cracked mylar most likely) and has a very dim display. I have not seen the dim display before, but I have replaced keyboards in other TS1000 a couple of times (with the very very good ZX8-KDLX).

Thank you all, I appreciate your time.

KB

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TMAOne
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Location: Waterloo, Ontario, Canada

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by TMAOne » Thu Sep 19, 2019 7:06 pm

Sounds like you're on the right track with corrupt ROM or ULA. The string that gets echoed from the one-byte PRINT command code is actually " PRINT ", or space-PRINT-space. Same idea with POKE. That mapping seems to be partially corrupt, and the echo strings contaminated.

I'll leave it to the smarter people to identify ROM or ULA.

The good news is that IF there's no other issues, the PRINT and POKE commands will function normally. It's just the screen representation of the 1 byte keyword that is polluted. Hopefully.

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Andy Rea
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Location: notts UK

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by Andy Rea » Fri Sep 20, 2019 1:26 pm

bad connection on the alternative address lines from the ULA ?

if everything else appears to be working then no fault on data lines or adderess lines from cpu to rom / ram.

try doing this

10 for t=0 to 63
20 print chr$(t);
30 next t

and run it....
or just type "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

and show your results. you will probably find a pattern ( a power of 2 ) to which characters are displayed incorrectly,

from this you may be able to tell which alt address line is wrong.

from what you have already said i'm gonna guess A7'

Regards Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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TMAOne
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Location: Waterloo, Ontario, Canada

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by TMAOne » Fri Sep 20, 2019 8:19 pm

See? There goes one now,...

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XavSnap
Posts: 757
Joined: Sat May 10, 2008 4:23 pm

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by XavSnap » Fri Sep 20, 2019 8:34 pm

IR=$1E00
R= %000* 0000
(*) Where the bit B4 is set to 1.

Code: Select all

000* 0000 "("
000* 0001 ")"
000* 0010 ">"
000* 0011 "<"
000* 0100 "="
000* 0101 "+"
000* 0110 "-"
000* 0111 "*"
000* 1000 "/"
000* 1001 ";"
000* 1010 ","
000* 1011 "."
000* 1100 "0"
000* 1101 "1"
000* 1110 "2"
0001 1111 "3"
0001 0000 "("
0001 0001 ")"
0001 0010 ">"
0001 0011 "<"
0001 0100 "="
0001 0101 "+"
0001 0110 "-"
0001 0111 "*"
0001 1000 "/"
0001 1001 ";"
0001 1010 ","
0001 1011 "."
0001 1100 "0"
0001 1101 "1"
0001 1110 "2"
0001 1111 "3"
001* 0000 "K"
001* 0001 "L"
001* 0010 "M"
001* 0011 "N"
001* 0100 "O"
001* 0101 "P"
001* 0110 "Q"
001* 0111 "R"
001* 1000 "S"
001* 1001 "T"
001* 1010 "U"
001* 1011 "V"
001* 1100 "W"
001* 1101 "x"
001* 1110 "Y"
001* 1111 "Z"
0011 0000 "K"
0011 0001 "L"
0011 0010 "M"
0011 0011 "N"
0011 0100 "O"
0011 0101 "P"
0011 0110 "Q"
0011 0111 "R"
0011 1000 "S"
0011 1001 "T"
0011 1010 "U"
0011 1011 "V"
0011 1100 "W"
0011 1101 "x"
0011 1110 "Y"
0011 1111 "Z"
schema.jpg

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by 1024MAK » Sat Sep 21, 2019 12:58 am

TMAOne wrote:
Fri Sep 20, 2019 8:19 pm
See? There goes one now,...
If you get the correct time of year, wave a light around, and if you are lucky, you may see a flash of more than one at the same time. But be quick, or you may miss them... :mrgreen:

Mark

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by 1024MAK » Sat Sep 21, 2019 1:03 am

KayBee wrote:
Thu Sep 19, 2019 6:14 pm
When I tap the PRINT key, I get "(PRYNT(" and when I use the POKE key I get "POKU."
Have you folks ever seen this behavior?
Which chips are in sockets?
And have you tried removing them from their sockets, visually checking the chip pins for dirt or tarnish, and if clean/okay, putting the chips back in the sockets?

If you need help with the above, shout out again ;-)

Mark

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XavSnap
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Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by XavSnap » Sat Sep 21, 2019 2:29 am

Hi,
But, something's wrong…
The level is high and in case of a cut PCB tack, the level will be "0" ,not "1".
I suspect the ULA input to be set to high every time.
Or may be short-cut with another pin...

Moggy
Posts: 1866
Joined: Wed Jun 18, 2008 2:00 pm

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by Moggy » Sat Sep 21, 2019 4:16 pm

1024MAK wrote:
Sat Sep 21, 2019 1:03 am
KayBee wrote:
Thu Sep 19, 2019 6:14 pm
When I tap the PRINT key, I get "(PRYNT(" and when I use the POKE key I get "POKU."
Have you folks ever seen this behavior?
Which chips are in sockets?
And have you tried removing them from their sockets, visually checking the chip pins for dirt or tarnish, and if clean/okay, putting the chips back in the sockets?

If you need help with the above, shout out again ;-)

Mark
Would agree with this especially if the ROM is a MOSTEK chip, as in my experience they really do tarnish quite visibly compared to other chips and a scrub of the pins with a fibreglass stick brings them up too scratch.

The pins on the left of the chip are typical of of how MOSTEK pins tarnish whilst the ones on the right of the chip have been cleaned as described above.
Attachments
SANY0202.JPG

Lardo Boffin
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Joined: Sat Nov 26, 2016 2:42 am

Re: PRYNT, POKU, bad ROM or ULA in TS1000?

Post by Lardo Boffin » Sat Sep 21, 2019 5:47 pm

I have a MOSTEK ROM - it looks like the ‘before’ half of the photo! :D I must get round to cleaning and testing it.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

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