Leningrad 1 (512k)

You once wrote that on Leningrad 1 extended memory up to
512k works normally - could you remember what letter RU7 is there and whether there is a delay
of the RAS signal, otherwise I made a circuit diagram here, installed mikruhi (albeit in a different way
LH21256 -12 and MB81256 -12 and 256k), and the computer is buggy - it resets, a picture with 48 BASIC appeared a couple of times (I guessed it from the set of different dots in the bottom
line), but it reset immediately. Maybe this glitch is due to the fact that I installed not
512, but 256k, or these are slow microphones, or maybe there is something else that needs to be done in the circuit besides the RAS delay?

2All: answer who knows.

$$$ With best wishes ... Alex

AG> You once wrote that on Leningrad 1 extended
AG> memory up to 512k works normally - could you remember with what letter RU7 and
AG> 2All are there: answer who knows.

At one time I shoved 1meg into L1 on regular RU5G. That scarf with RU5s was the size of Leningradka itself :). In general, I took the diagram from the ZX-REVIEW for 1991, and I think it was about numbers 3-4, I don’t remember. Well, there seems to be a circuit for ID3... So,
I had this thing working for a little less than 8 hours) - the multiplexers were all(!) dead.
True, I managed to copy one disk, rolling it all into memory... :) It worked out quickly...

RomanRom2 [Team MAZDAI - RULEZ]

AG> You once wrote that on Leningrad 1 extended
AG> memory up to 512k works normally - could you remember with which letter RU7 and
AG> are there, is there a delay
AG> of the RAS signal, otherwise I here I made a circuit diagram, installed mikruhi (although in
AG> there is a difference between LH21256 -12 and MB81256 -12 and 256k), and the computer glitches -
AG> resets, a couple of times
AG> a picture with 48 BASIC appeared (I guessed from the set of different points in
AG> bottom line), but immediately reset. Maybe this glitch is due to the fact that
AG> I installed not 512, but 256k, or these are slow mikruhi, or maybe in the
AG> circuit, in addition to the RAS delay, something else needs to be done?

For Leningrad, the ones with the letter “G”, or similar
slow ones, are best suited. The delay should be set at ras to about 100 picoforads, and even better, at the ras gap, a 100-510 ohm resistor, whichever one you choose. If you expanded from 48, then
a delay is required not just on ras, but on the signal going to the processor clock and
memory, but not to the clock generator.

Regards, Alex from FFC COMPUTERS.

You once wrote that on Leningrad 1 extended memory up to
512k works normally - could you remember what letter RU7 is there and whether there is a delay
of the RAS signal, otherwise I made a circuit diagram here, installed mikruhi (albeit in a different way
LH21256 -12 and MB81256 -12 and 256k), and the computer is buggy - it resets, a picture with 48 BASIC appeared a couple of times (I guessed it from the set of different dots in the bottom
line), but it reset immediately. Maybe this glitch is due to the fact that I installed not
512, but 256k, or these microphones are slow, or maybe in the circuit, in addition to the RAS delay, something else needs to be done?

2All: answer, who knows.

12 Dec 97 02:02, Roman Khroupnin wrote to Alex Gofman:

AG>> Once you wrote that in Leningrad 1 it works normally
AG>> extended memory up to 512k - could you remember with what
AG>> letter there are RU7 and 2All: answer who? knows.

RK> At one time, I shoved 1meg into L1 on regular RU5G. That scarf with
RK> RU5 was the size of Leningradka itself :). In general, I
RK> took the diagram from the ZX-REVIEW for 91, and I think it was about numbers 3-4, I don’t remember. Well
RK> there seems to be a circuit diagram for ID3... So, this thing worked for me
RK> for a little less than an hour 8) - the multiplexers are all(!) dead. True, I
RK> managed to copy one disk, rolling it all into memory... :)
RK> It worked out quickly...

And at one time I expanded the memory on Subj to 128k using my own scheme
obtained by processing the Pentagon scheme. Everything seemed to be working, but at the beginning of page C000h, the first six bytes kept getting corrupted. In general
then I got tired of suffering and bought a Pentagon128. Although it was a pity: in that Leningrad there were all sorts of gadgets - about 5-6 pieces. Including
disk drive controller, music processor, etc.

Best regards
┬ ┬┌┐┬┐ ┐┬┬
╨ґ╨╙ґ╨╙ ╨ ╨

VY> And at one time I expanded the memory on Subj to 128k using my own scheme
VY> obtained by processing the Pentagon scheme. Everything seemed to work, but at the beginning of page C000h, the first six bytes kept getting corrupted. In general
VY> then I got tired of suffering and bought a Pentagon128. Although it was a pity: in that
VY> Leningrad there were all sorts of gadgets hung - about 5-6 pieces. Including
VY> disk drive controller, music processor, etc.

I've had a similar machine working for three years now, but there's still a lot of work to be done, but everything
is assembled based on Leningrad 1. IMHO, this version of the Speckie is the best!!!

VY> at the beginning of page C000h, the first six bytes kept getting corrupted. In general

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I had the same thing, but the cells with 0000h were damaged, this was detected by
converting the /WE signal for RU-sheks to log.1 with A14=A15=log.0 (I think
there is no need to draw a diagram - ordinary logic)

Wed Dec 10 1997 16:21, Alex Gofman wrote to Tyukaev Eugene Vladimirovich:

AG> You once wrote that on Leningrad 1 extended
AG> memory up to 512k works normally - could you remember what letter RU7 and
AG> are there? there was a delay in the RAS signal, otherwise I made a circuit, installed
AG> mikruhi (albeit in a variety of LH21256 -12 and MB81256 -12 and 256k), and the
AG> computer is buggy - it resets, a couple of times a picture with 48 BASIC
AG> appeared (I guessed it set of different points in the bottom line), but immediately
AG> was reset. Maybe this glitch is due to the fact that I installed not 512, but 256k
AG> or the microphones are slow, or maybe there is something else that needs to be done in the circuit besides the RAS
AG> delay?

AG> 2All: answer, who knows.
Personally, I use PENTAGON 128, but for a very long time I'm interested in expanding the memory of
SPECTRUM. And if it doesn't bother you, then please explain.

With best wishes, Vladimir

VY>> circuit obtained by processing the Pentagon circuit. Everything seemed to work,
VY>> but at the beginning of page C000h, the first six bytes kept getting corrupted.
VY>> In general, then I got tired of suffering and bought a Pentagon128. Although it was a pity: in that Leningrad there were all sorts of bells and whistles - about 5-6 pieces.
VY>> Including the disk drive controller, music processor, etc.

AL> I have had a similar machine working for three years now, but there are still a lot of improvements,
AL> but everything is assembled on the basis of Leningrad 1. IMHO, this version is a Speckie
AL> the best!!!

Oh, I remembered, in the same ZX-REVIEW, for the same 91 years, there was a scheme for upgrading
Leningrad1 to 128 kilos on the RT4. I remember, I ordered the board and ROM by mail. About two months passed. No, it's here. Well, I assembled it, launched it, and it worked. Since then, in one of my many (we even had a story in 5015 about my bag with
sinclairs 8))) sinclairs have been working.

AL> there are a lot of improvements, but everything is based on Leningrad 1. IMHO,
AL> this version of the spec is the best!!!

Well, of course, after you finalize it! :)
Sincerely
┬ ┬┌┐┬┐ ┐┬┬
╨╜╨╙╜╨╙ ╨ ╨

VY> Well, of course, after you finish it! :)

There are about ten of these machines in 5020, and there have been no complaints about the work. It's a pity we weren't able to install the board four years ago. :-(((