Leningrad1 /128K

I decided to “bring my computer to mind” a little - untangle a bunch of wires and
connect them into bundles. After this procedure (I had to resolder some things), glitches appeared:
the test ROM tests normally, but sometimes it gives an error about the configuration port of bank 0
sector 3 written 00000000 read 00000100 (sometimes 00000111). Similarly with the t_rom64 test (along with the question - what is the T-constant and what does the int-vector show?)
The RAM-TEST test from the ZX-POWER II does not find any errors at all.
Well, that’s okay, but I do a reset, go to menu 128 (from Glitch ;), look at the sampler - pages switch, run a simple test in BASIC (in
pages 7, 4, 3, 1, 0 I write the corresponding numbers, and then read them) -
here the system hangs dead, and in the 0 bit of the configuration port
1 is written. The same thing happens from 128 and from 48 (with open port). But
this glitch does not always occur. I also can’t launch ALASM (as well as
some other programs) - it freezes.
These are the jokes. I have repeatedly checked all the wires going to the expansion circuit - everything is fine, and everything is fine on the board, but the glitch remains :(((

$$$ With best wishes ... Alex

04-Nov-98 11:44 Alex Gofman sent a letter to All:

AG> I decided to “bring my computer to mind” a little - untangle a bunch of wires and
AG> connect them into bundles. After such a procedure (I had to resolder some things)

What signals _specifically_ were woven into bundles? How long did they (the tourniquets)
turn out? What is the bundle: “ribbon” (flat cable),
or “in a bunch, very tightly”?

AG> glitches appeared:
AG> test ROM tests normally, but sometimes it gives an error configuration port
bank 0
AG> sector 3 written 00000000 read 00000100 (sometimes 00000111). Similarly
with

The configuration port (PC) switches poorly. What resistors (value)
connect the data bus in the computer? How long is the harness in which
there are data bus conductors (D0, D1, D2, D3, D4, D5) going
to the PC MS? If the PC's MS is TM9, then look at which strobe goes to input "C" when accessing #7FFD, positive or zero? If AY-8910(12) is in the socket, then take it out and repeat the test. Hang it _directly_ on the MS PC and on other blocking capacitors
at 0.1mkF (ceramic ones only! KM-3,4,5,6; K10-17).

There is also an option (just don’t laugh!) that you have a “bad” power supply
(+5V and common wire) “divided” to improvement of memory expansion.
After upgrading the wireI didn’t “throw” the power supply to other points
of the board?

AG> using the t_rom64 test (in passing, the question is - what is the T-constant and what does the
AG> int-vector show?)
AG> The RAM-TEST test from the ZX-POWER II does not find any errors at all.
AG> Well, that’s okay, but I do a reset, I go in in menu 128 (from Glitch ;), I look at the
AG> probe - the pages switch, I run a simple test in BASIC
(in
AG> pages 7, 4, 3, 1, 0 I write down the corresponding numbers, and then read
them) -
AG> this is where the system freezes completely, Moreover, the 0 bit of the configuration port
AG> is written to 1. The same happens from 128 and from 48 (with an open
port). But

Do you remember to do CLEAR 49151 (or lower) before “clicking” pages
from BASIC (after RESET)? ;)

AG> this glitch does not always occur. I also can’t launch ALASM (as well as
AG> some other programs) - it freezes.
AG> These are the jokes. I have repeatedly checked all the wires going to the
AG> expansion circuit - everything is fine, and everything is fine on the board, but the glitch remains
:(((

More accurate information is needed:

1. What computer board? (“ZONE-48”, one RU5 line ?)
That is, what kind of board was there before the conversion to 128K.

2. What scheme was the memory expansion made of?"broke", then provide the _complete_ expansion scheme in ASCII, because... there are many of them (schemes) and each has its own “subtleties”.
It will be much easier.

Sincerely, Felix!