RGB card ..how to connect /part 2/

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RGB card ..how to connect /part 2/

sorry ..i can't edit /DELETE/ my EMPTY post Wink /
so
i have PRAVEC'82 /bulgarian clone of APPLE II+/
and
RGB card...

this card have one WIRE who must be connected....? where Smile ? or just my PRAVEC'82 have not PIN for connection Sad

i put this card already on SLOT 7

and maked a cable ..to connect on LCD /trough SCART/

1. how and where to connect this WIRE from RGB card ?
2. is this schene ..look... WORKING Smile ?

tnx in advance

Georgi

http://postimage.org/image/n6ztxn9t9/
http://postimage.org/image/4q5f6ttv1/

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Re: RGB card ..how to connect /part 2/

It probably connects to pin 2 on the four pin video connector on the motherboard. I have Taxan card that does that.

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Re: RGB card ..how to connect /part 2/

hello drJones,
just in case that the clone does not have the pinconnector same like apple II ( some clones don´t have that ) that cable for input from Apple II must be served with the video composite signal which is sent to the TV/Monitor ( from videojack at the rear side )... , just besides a matter of interest... could you also send a link to a picture of the backside of that card ?
sinceely speedyG

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Re: RGB card ..how to connect /part 2/

..
tnx SPeedyG
tonight will make pictures from inside of Pravec'82
and here are more pictures of back side of RGB card to

http://postimage.org/gallery/55u3vdge/f7aa4c40/

tnx in advance !
btw. on Pravec MB have 4 holes /where must have 4 pins Wink .../
so i must soldier this 'cable' on 3rth hole Wink ..maybe
or directly on TVout
...

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Re: RGB card ..how to connect /part 2/

here are pictures Smile

http://postimage.org/image/if04gfrsd/
http://postimage.org/image/f6vn3e5il/

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Re: RGB card ..how to connect /part 2/

Hello drJones,
it seems that the original rev.7 board was the the source for this clone. You are correct with the 4 holes without posts and counting from the outside of the board towards to the slot 7 beginning outside with 1 and the hole closest to the slot being 4 the 3rd hole should have contact with the inner cable of the plugsonnector of the monitor and that hole will give same like the inner wire to the plugconnector the desired FBAS-signal ( composite video ).
sincerely speedyG

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Re: RGB card ..how to connect /part 2/

tnx mate !
so
i will solder a cale with HOLE 3 Smile and all must work Wink ?
btw do You saw my scheme of
video to SCART /LCD/ ?
is this scheme ..working ? from Your point of view ?

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Re: RGB card ..how to connect /part 2/

Hello drJones,
please befor soldering confirm yourself by making measurement between pin 3 and Videoplug connector....
not seeing the bottom of the mainboard in the pictures - there still can be a change in the oder of the pins....
if connection is correct as explained ( pin 3 and inner wire to videoplug connected ) then you can continue....

about the scart and LCD i can´t give advice because i haven´t tried...
i´ve connected my Apple computers to a RGB Monitor from Philips....
for connection to LCD Monitor i´ve used a converter .....

see former threads in my track list....
sincerely speedyG

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Re: RGB card ..how to connect /part 2/

tnx for advices...will do all ..drom Your instruction Wink

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Re: RGB card ..how to connect /part 2/

Hello,

just added a page with cableconnections from Apple to Philips RGB-Monitors.....
http://www.harrowalsh.de/Elektronik/APPLEBOX/applephiliipsRGBconnections.htm

sincerely speedyG

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Re: RGB card ..how to connect /part 2/

so
i connected cable on HOLE 3 /from right to left/
when i started Pravec;82
nothing happend.. computer did not started Sad
after that i re-sloted all controlers
and tryed w/o RGB card /to see is coputer still OK Wink /
computer started normaly and loaded a game from a floppy Smile
after that i put ONLY CARD in slot 7
computer BOOTed normaly
and after that i put cable from RGB card over PIN who i soldered on HOLE 3
and connected my RGB->SCART cable on LCD
computer started
but
i did not seen any signal on LCD
and after 20 seconds i has smeled a BURNING CHIP Smile ..i stoped computer imediatly
the smell was fom RGB card ... but computer is OK Smile

so..
maybe RGB is BAD...
or
is not HOLE3 ?
or
i already BURNed this card ?
Smile

can i do some more tests ?

georgi

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Re: RGB card ..how to connect /part 2/

hello georgi,
that sounds like you did NOT check the connection from Pin 3 to the inner cable of the videoconnector......

please befor soldering confirm yourself by making measurement between pin 3 and Videoplug connector....
not seeing the bottom of the mainboard in the pictures - there still can be a change in the oder of the pins....
if connection is correct as explained ( pin 3 and inner wire to videoplug connected ) then you can continue....

I explained that: before using the card, you must check this before !
At those 4 pins there should be: 1 pin = Ground, 1 Pin = composite Video, 1 Pin = -5V and 1 Pin = +12 Volt !
As i explained - i can´t see the bottom of the mainboard and therefor the pin 3 must be checked to have connection with inner part of the videoconnector to make sure that pin 3 is the correct pin !
It seems that you hit -5 Volt !
This would have caused ( indicated by smell ) that pin 2 of the 74LS164 ( identified by the picture given above ) might have been fried....
the good news is that this chip is still availiable and not too difficult to get.....
but at least that chip must be replaced !

And again:

BEFORE using one of the holes at the mainboard you MUST REALY BEFORE USING THE CONNECTION CHECKOUT, THAT THAT HOLE HAS DIRECT CONNECTION [ 27 Ohm to 50 Ohm ] WITH INNER CABLE OF THE VIDEOPLUG !!!

For better understanding download "Understanding the Apple II" from Jim Sathers
go to:
http://mirrors.apple2.org.za/
choose from list:
Apple II Documentation Project
choose from list:
Books
choose from list and save to harddisk:
Jim Sather - Understanding the Apple II.pdf

see there: page 209
and look to area around Q3 ( Video-Output-transistor...)
sincerely speedyG

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Re: RGB card ..how to connect /part 2/

this must ne good newz Smile ...maye card is stil is not burned Wink

here are Pics from any side and view Smile i thinked You /SteevyG/ look at on them Wink

http://postimage.org/image/tu9x6wrcd/
http://postimage.org/image/5chtj0orx/
http://postimage.org/image/y9nqyfect/
http://postimage.org/image/ku0q8z5v1/
http://postimage.org/image/i17ioy5il/
http://postimage.org/image/og6jlmc8d/

do You see any wrond or ???? explanation ?

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Re: RGB card ..how to connect /part 2/

hello drJones,
well the pictures are really good, but you must allways bear in mind that even though the pictures are good the colors differ from monitor to monitor and from camera to camera....
i´ve looked very close to the pictures but some impression might be not that sure like just smelling directly at the chips.... but i´ll just spot out that at the 74LS164 the color of the plastic slightly changed below the marking of "164" which is usually a sure indicator that this chip has been fried and that should confirm by smell.... further examination of the etched lines show that several parts of the 74LS164 lead up to the 74LS74 too and that chip seems to show something like a "micro-crack" at the side opposite from the notch - so if it would be my card i would "not take the risk" but instead change that chip too - specially because the chip is common and cheap.... and i would at least also sweep the electrolytic capacitor from kea with the value 22µF / 16 Volt against a similar one with the same value ( but pay attention to insert again the correct way with the plus pol at the same side and the minus pol in the same hole ! minus pol towards edge of the card ! ) and of course the same also with the electrolytic capacitor at the bottom edge of the card and of course also at that point you must keep the correct position of the polarity .Changing this 4 components would amount to some 3 to 5 U.S. Dollars.... all together....

And very important : i would examine very carefully the trimming resistor ( 100 ohm to 250 ohm - better 250 ohm ) standing upside on the mainboard close to the opposite side of the soldered cable from the videoconnector .... and probably change that too.....

but i just repeat again - your nose will be a sure indicator beside of technical knowledge and view of the components.... bad smell is a sure indicator at damaged circuits or burned resistors.... so use your nose or use the nose from somebody else if you are a smoker....
sincerely speedyG

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