PC-01 Lviv http://pc01.lviv.ua/forum/ |
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A new member and his computer! http://pc01.lviv.ua/forum/viewtopic.php?f=13&t=326 |
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Author: | orest [ 20 Apr 2016, 13:36 ] |
Post subject: | Re: A new member and his computer! |
Here you are. You can use BC847B or similar instead of КТ315. |
Author: | Lesarthois [ 20 Apr 2016, 18:24 ] |
Post subject: | Re: A new member and his computer! |
Yeah, unless I gut off a Soviet radio I have around (do you know they were readily available in France in the 80's?) I won't be able to find that precise transistor, but it seems to be a rather generic one. I might even find an equivalent in the pile of transistors I have around. I'll try to make something this week or this week-end. |
Author: | doorsfan [ 20 Apr 2016, 21:22 ] |
Post subject: | Re: A new member and his computer! |
Zelya, please, just translate to our French friend my manual that was written some years ago on this forum. I found it: quoted by gtament in 5th message in this branch http://lvovpc.ho.ua/forum/viewtopic.php?f=2&t=86 You need in 74LS02 IC BTW more info about OREL BK08 enchanced clone of ZX-Spectrum (made in Dnepropetrovsk) You may find on mostly ZX Spectrum relative forum zx-pk.ru |
Author: | Zelya [ 21 Apr 2016, 11:59 ] |
Post subject: | Re: A new member and his computer! |
doorsfan As I understand your video "upgrade" allows to invert colors too? I'm not technical guy, and I don't understand your explanation, but I'll try to translate Video output modification: 1. Connect +12V to the pin 1 through 300 Ohm resistor 2. Connect sound from beeper to pin 7 through 10K Ohm resistor 3. Remove 3 electrolytic capacitors at the border of motherboard, near TV jack 4. Solder 555ЛЕ1 above ДД62 (555ЛЛ1) with the next connections: pins 3, 6, 7, 8, 14 should be connected to ЛЛ1; pins 2, 5, 9 should be flexed to connect them with pins related to 3,6,8 (right?). Pins 11,12,13 - are not use, can be just flexed outside. Pins 1,4,10 should be flexed outside too and connected to "minus" positions of removed capacitors С54, С53, С55. DIN7 to SCART connection: 1 - to 8 and to 16 though 390 Ohm resistor 2 - 20 3 - 7 4 - 11 5 -15 6 - 4 (optional to 5, 9, 13) 7 - 2,6 PC-01 Lviv schema is here: http://www.lvovpc.cu.cc/files/lvov_sheet.rar |
Author: | Lesarthois [ 21 Apr 2016, 18:15 ] |
Post subject: | Re: A new member and his computer! |
Interesting things! I think I'll try first the 3 transistors solution. It's cheap to do, and I can manage to put that on the video cable. The less I mess into the computer, the better I feel. I even have ready-made solution for the cable : for some reason, megadrive sold in France had an additionnal box on the SCART cable : What's more to ask for? Good advice anyway on the sound output, I'll keep that in mind. And I'm going to use the 12V. In computers, the 5 V line is usually used for the RAM and CPU, so anything that draw current from it can cause troubles; on the other hand, that 12V being present on the extension port mean that it's made to draw power from it, so 3 transistors won't strain the power supply I think I'm going to use a LM 1881 to get a better and standardized video sync. This mgiht solve the issue of the "upper screen ripping" I have seen on some video mods. |
Author: | Lesarthois [ 27 Apr 2016, 03:43 ] |
Post subject: | Re: A new member and his computer! |
Today I received DIN plugs to solder, so I opened the computer again to work on it. And, I somewhat expected it, but the owner, when working on his RF video mod, used the DIN as a simple support for soldering his wires, and so, moved them out of place (for example, the pin 7 is populated, but pin 6 was empty. This explains me why the video was so wobbly when I tried to wire it; there was no ground connected. Anyway, I need to rewire this DIN plug correctly first, then check for a 12V line I can take power from. |
Author: | Lesarthois [ 27 Apr 2016, 21:56 ] |
Post subject: | Re: A new member and his computer! |
So I tested it quick. I get RGB out, with the help of an old 5+ power supply. I noticed that I get brighter colors and the right one from the channel if I link together the sync wire and a color wire so, this lead me to question is maybe the Lvov output was in fact TTL RGB? Everything linked normally : Sync and green linked together : Also I noticed that depending on the color channel, the screen upper ripping would get worse, with the blue channel even puttign the TV out of sync. Regardless of any solution, I think that using a LM 1881 to get a clean sync signal is more than needed. I found this page about the Byte ( Байт) computers : http://zxbyte.ru/byte_connection_to_tv_and_monitors.htm Google Translate isn't very at ease with it, but if I get it right, that's TTL RGB, and one of the given solutions for is is this schema : There is an added part with the diodes, but else, it seems to be the same solution. Except that this one introduce brightness in the mix. What do you think? |
Author: | orest [ 27 Apr 2016, 23:02 ] |
Post subject: | Re: A new member and his computer! |
Yes, it is a TTL level. That's why we're using those R5-R7 variables, to manually correct each color level on the input (very usable mod, by the way). In my case final result is something like this. But much, much brighter colors. |
Author: | Lesarthois [ 28 Apr 2016, 00:08 ] |
Post subject: | Re: A new member and his computer! |
Oh, perfect! So it's not some odd exotic video output, just a fade in the world of computers. And that's plenty of designs I can try if the result isn't convincing for me. In the meantime I think I'm gonna test some games on the computer as well. I saw a post somewhere on the forum to convert games to sound format. |
Author: | orest [ 28 Apr 2016, 16:14 ] |
Post subject: | Re: A new member and his computer! |
Quote: Oh, perfect!
It's TTL level signal, but not a TTL logic, i suppose. Sorry for misleading.
So it's not some odd exotic video output, just a fade in the world of computers. And that's plenty of designs I can try if the result isn't convincing for me. In the meantime I think I'm gonna test some games on the computer as well. I saw a post somewhere on the forum to convert games to sound format. |
Author: | Lesarthois [ 28 Apr 2016, 19:12 ] |
Post subject: | Re: A new member and his computer! |
I'll mess around when I'll get all the needed components and post about what I found. Anyway the result is unlikely to be 100% accurate, but as long as the display is "close enough" that will do. Where is the fun if everything is too easy? |
Author: | Lesarthois [ 12 Jun 2016, 03:41 ] |
Post subject: | Re: A new member and his computer! |
Bumping the thread! I finally received all the needed parts to make the circuit.. and I get nothing. I have to check my wiring, and the circuit, but I also thing that the video out on the computer could be messed : as I explained before, a previous owner soldered wires on it to make a video RF out mod, and I think that he might have removed the wires and resoldered them on the video out at random. Is there any document showing the exact originl point for the video out? |
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