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avatar_Sebastian Blanco

building the aleste 520ex (cpc/msx russian clone)

Started by Sebastian Blanco, 01:23, 01 November 19

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Sebastian Blanco

#50
 ;D

Sebastian Blanco

Almost there i soldered most component, discovered that in my kit there was a lot of missing resistors i have to purchase before finishing.Now the fun part deciphering the capacitor list.
I got most there but what is:
CAP ??  i suppose that all the CAP are 0.1uf (theres a big bag of them in the kit)

470 (is nano ? is pico ?)
1h ?
47h ?.




Bryce

Well if you go by the generally accepted rules: If no denominator is shown, then it's the base denominator, with capacitors that would be pico. But it would make more sense to look at where the capacitor in the circuit is and what's its function. That will definitely tell you what value range it should be.

As for "H", I suspect that they have just named an inductor with Cxxx, again a quick look in the schematic will answer this too.

Bryce.

Sebastian Blanco

After checking out this https://www.cia.gov/library/readingroom/docs/CIA-RDP80-00809A000700030074-5.pdfWho could now the CIA will help me out of this one  :o And also asked a russian guy and he confirmed the information.
This are the equivalents to the russian values:



Sebastian Blanco

Quote from: Bryce on 22:15, 20 September 20
Well if you go by the generally accepted rules: If no denominator is shown, then it's the base denominator, with capacitors that would be pico. But it would make more sense to look at where the capacitor in the circuit is and what's its function. That will definitely tell you what value range it should be.

As for "H", I suspect that they have just named an inductor with Cxxx, again a quick look in the schematic will answer this too.

Bryce.
Well here they are for example some of the capacitors called CAP on the shematic also theres a single resistor in the schematics called RES for some reason.
I suppose all this caps (RES) should be 0.1uf ? they all seem to be filter caps.




Sebastian Blanco

#55
Have been reading the russian forum thread about build the aleste like 150 times
They are several mistery components on the BOM, from the thread i get they are not clear.
Theres a lot of going up and down on this values.

This is the list and what i could find of possible correct values:
C15 Less than 47pf (from forum post)
C16 Less than 47pf (from forum post)
C17 Less than 47pf (from forum post)
C18 ?????? nothing
C3 6800pf (from forum post)
C4 1000pf (from forum post)
C5 510pf (from forum post)
R136 2K (from a picture of old board)

Sebastian Blanco

This is from the 30+ pages thread the only relevant information to building the missing parts on the bom:

#If in essence - C3 - 6800pF 10%, C4 - 1000pF 10%, C5 - 510pF 10%
#What are the denominations of C3, C4, C5?
   
    And no one knows this.

    As for the C5 Conder, I won't say what capacity I put, I just don't remember. Now instead of him I have made revision number 2. Only the revision was made not on TM2 but on IR16 as in the famous photo on the internet. With TM2, my computer was buggy, apparently there was some kind of jamb in the circuit, or maybe I soldered something wrong. I didn't understand.

    When assembling the computer, in place of C3, I stuck a 0.22 microfarad condenser, but then it had to be selected together with a resistor R5. Otherwise, there will be glitches in games and demos. What capacity is now installed I will not say, you need to disassemble the computer, but I have it already packed in the case. And I'm sure that now I have it installed in the wrong capacity, which should be. Here it is necessary for connoisseurs of circuitry to understand. I asked the owner of a real car to specify the capacitance C3 and the resistance value R5 on his computer. Six months later, that is still waiting for an answer)))

    Well, C4 everything just as it is written in the manual for start-up and commissioning of computer "Depending on the instance D65 is dictated by the need of the capacitor C4, and it is defined by the absence of small failures horizontal sync in different graphics modes. " so you probably won't need it.
   
    QuoteMessage from Mick View Post
    And instead of R136, a jumper or a break or a cut with a face value (which one)?
    At the first start, I installed a 2.7k resistor as R136, by analogy with the R6 resistor. After the assembly of revision number 1, this rezyuk and the VD12 diode were completely removed from the board.



#Please tell me the ratings of the CAP capacitors: c15, c16, c17

   I think they are very small, for example 4.7pF with a R62-64 rating equal to 50 ohms. Your task is to remove fine noise from the image in the form of light ripples, if there is any. In any case, this capacity should not be more than 47pF .
   At 220 ohms, theoretically, 1 pF is sufficient. The value of this resistor does not matter. It is clear that it must be at least 50oM.
   
   
   
#What is the C8 capacitor used for and what value should it be?
 
      С8 extinguishes the "needles" bursts of invalid signal HY * to the D65 / 10 pin, which can occur when the address is switched at the ROM D10 input. Select the minimum denomination at which there is no extra "garbage" on HY *. Set it to 47pF and watch the waveform. Increase until you get an acceptable result. Or decrease it. Remember that the oscilloscope probe itself has a capacitance of 5-15pF.
      If I'm not confusing anything, then this signal with level 0 is generated every 27 lines of the screen and is equal to the length of one line. Obviously this is one of the favorite CPC tricks for changing the palette or parallax effect.
     
     
     
#After installing Conder C3 with a capacity of 6800pf, the computer did not work stably.
    In some games, sprites began to deteriorate, demos stopped running,     which worked somehow before replacing the conductor. Before that, I had a 0.22 microfarad capacitor and a 2k resistor R5 installed. While taking a timeout. As soon as free time appears, I will again carefully look at everything that I soldered, maybe where I made a mistake ...
    This is strange. Next time, if you can take a picture of the oscilogram at the R input of the trigger? For example 6.8 try little more. But 0.22uF looks too big. With another

    QuotePosted by Dmitry2012 View Post
    I would like to clarify the denominations of some details, specifically interested in: C5, R134, R6, R136. Another question about the improvements, which are described in the computer setup manual. Are the diagrams correct there, are there errors in them?
    R134 - from 33th to 100th. The problem with this chain only affects the performance of the palette. It cannot lead to a computer crash.
    About the C5 was written above. Actually it is not needed. It was added to the circuit after the board was laid out. Any smallest denomination or none at all.

    R6 - 1..2k simple pull-up is responsible for screen blanking. It cannot lead to a crash. Screen blanking by register bit D32.Q4
    R136 - 1..2k high resolution mode is formed by D32.Q1 . ( HIGHTY ) Should not lead to a crash. Switches the address generator to high resolution mode.

    D32.Q2 ( HIGHTX) the signal switches the clock generator to high resolution mode. I don't remember the reason why two separate devices for one and the same functionality are controlled separately. But it seems it was for a more "soft / hidden" mode switching. I will remember - I will say.



#Hello !
    #As I see you have a board version 1.004, which means that it does not needed any correction.
    For the first start, I recommend not to install a coil "DR2"

Bryce

#57
C15 / 16 / 17 are for tuning the sharpness of the picture, 47pf sounds like a reasonable value, but you could probably try different values right up to about 220pf to get the picture you prefer.

Can you post the part of the schematic where C3 / 4 / 5 are so that I can see what they are doing.

As for R136, I'd guess it will need to be a pretty low value, probably 10R or there abouts? It seems to be there to avaoid bus contention.

Bryce.

Edit: Just spotted C4 above, you could probably leave this out completely, It's there stretch the sync signal, if the picture isn't stable with no capacitor, then try different (pf value) caps until the picture stabilises.


Sebastian Blanco

This is are captures of the offensive caps in question :








Bryce

Wow, the timing of the circuitry must have been a mess, almost all of these are to stretch / buffer signals. C3 is a bit of a mystery.

Bryce.

Sebastian Blanco

Quote from: Bryce on 08:54, 22 September 20
Wow, the timing of the circuitry must have been a mess, almost all of these are to stretch / buffer signals. C3 is a bit of a mystery.

Bryce.
Ok, the only cap that i have no idea of the possible values is C18, do you have an idea of what i can trow in there ?.
https://ibb.co/rFhLStB
Also what you think about installing sockets where the mystery caps go to swap them and test ?, this can work out for caps using precision socket pins they seem to be a good fit.

Bryce

I'd guess it's a small ceramic cap, maybe around 47pf? Nothing wrong with using a socket for trial and error, but I'd remove the socket once I'd found a suitable value.

Bryce.

Sebastian Blanco

Quote from: Bryce on 08:31, 27 September 20
I'd guess it's a small ceramic cap, maybe around 47pf? Nothing wrong with using a socket for trial and error, but I'd remove the socket once I'd found a suitable value.

Bryce.
Great gonna do so :D .Also got this info from the russian forum:
Judging by the scheme, C18 is needed to adjust the PLL FDD of the drive (PLL FDD) and should be set in case of problems with reading from the drive. Its capacity should be within tens of picofarads or several hundred picofarads.

Bryce

If it's for the FDD PLL you may need more stability. If the value works, but is unreliable (only works on certain days), you may need to use a foil capacitor instead.

Bryce.

Sebastian Blanco

Almost there, assembled 99% components installed.Run some quick checks for power and clock on the cpu only.Draws 2.1 Amps at 5.0v.Got 3.3mhz on the scope seem to be a correct clock signal for a Z80 ?, the speed for a CPC should be 4 mhz.Still unsure how this thing works, next i have to add some missing caps and do the RGB cable to see if i got a picture
At least it didn't catch fire but hell the soviet memory run hot! after a wile of being power up the fill quite warm!. ;D






Bryce

CPU's don't have an exact clock speed, they run at whatever clock you give them (within their permissable range).

Bryce.

Sebastian Blanco

Its alive master ! its alive its alive !  :o



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robcfg


deepfb

Congratulations! I soldered everything in our board, but I don't have the files to write on the EPROMs. Could you please share them? Thank you!

Bryce

Great work Sebastian. A job you can be proud of.


You should probably let people know which value capacitors you chose to help others who are building one.

Bryce.

Kris

Quote from: Bryce on 09:09, 29 September 20You should probably let people know which value capacitors you chose to help others who are building one.

Bryce.

+1

A full list would be much appreciated :D


Sebastian Blanco

#71
Thank for the congrats guys!, and thanks to Bryce for all the help.
Used the components in the BOM for most of the board.
Here are the components installed i choose, marked as CAP and RES on the schematics:
C15 22pf
C16 22pf
C17 22pf
C18 22pf
C3 6800pf
C4 1000pf
C5 510pf
C8 1n
R136 2.2K

Anyway this components are enough to power up "OK" but this don't mean that this will work stable running software.
Have to do some testing before declaring victory on this.

Sebastian Blanco

Quote from: deepfb on 06:19, 29 September 20
Congratulations! I soldered everything in our board, but I don't have the files to write on the EPROMs. Could you please share them? Thank you!


This are the aleste roms:
https://mega.nz/file/IpNjVAxK#hjs2xH0Bj7YyhHjh6dU-nIQoZ9kpkUE1kfRmsP6N7Q8
https://mega.nz/file/54UVVAwa#Ohrdk4O9upPBdF_E3q1pUA_N-vvTUDEAs985wJ0zkLQ

Bryce

Quote from: Sebastian Blanco on 19:45, 29 September 20
Thank for the congrats guys!, and thanks to Bryce for all the help.
Used the components in the BOM for most of the board.
Here are the components installed i choose, marked as CAP and RES on the schematics:
C15 22pf
C16 22pf
C17 22pf
C18 22pf
C3 6800pf
C4 1000pf
C5 510pf
C8 1n
R136 2.2K

Anyway this components are enough to power up "OK" but this don't mean that this will work stable running software.
Have to do some testing before declaring victory on this.

For those not used to ordering capacitors: C4 and C8 are the same value - 1000pf = 1nf. C3 will also usually be sold as 6.8nf.

Bryce.

IRIOS


Hello,
I am mounting the computer (ALESTE PCB 2018) and I do not have the reference of U5.
Would it be possible to have the reference of the U5 component?

Thanks a lot.
Best regard
Irios

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