[Coco] CoCo3 to KV-1311CR Monitor cable.

[Stephen H. Fischer]

OK, 

Marty talks about getting 5 Volts all over the place but does not address what I have done. So: 
----------------------------------------------------- 
Hardware people, I messed up saying Green was 6 and then in the next line 5. 

I measured the resistor in the sync line at 68 ohms. 
I remember the RGB resister value was from testing so that the full color range is available. (76 ohms) 

Please help me make this better for the person needing this. In particular the value of the resistor in the sync line.
---------------------------------------------------- 
Construction: The CoCo3 has a space for a little board and a cable path from the RGB connector to that space.

The ten pin connector on the underside of the CoCo3 may be hard to find, when I needed one I knew which of the ~ 6 Electronic Surplus stores to go to. I suspect that the 34 pin connector came from the same place, with Rainbow Colors of course. Any 34 pin cable with a connector that mates with the Sony will work.

I put the 74ALS02 on the little board and just supplied 5 Volts from someplace inside the CoCo3.

The 76 ohm resistors are just in line with the RGB signals coming out of the CoCo3 RGB connector (The CoCo3 Service Manual is online).

The Hsync and the Vsync are fed into one of the gates and the output connected to the Sony with the 68 ohm resistor.

The unused wires in the 34 conductor flat cable are just tied up with some tape.

If the Cable needed to be connected to a different CoCo3 the power line would need to be disconnected and 5 Volt supply in the new CoCo3 installed.
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Yes this is not a diagram, others who could do this in their sleep can see it in their heads as I do.

I still think Marty published a diagram in Rainbow, but in the time it would take to find it or actually draw the diagram is too long.

TIA

SHF
 
----- Original Message ----- 
From: "Arthur Flexser" <flexser at fiu.edu>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, February 10, 2015 4:03 PM
Subject: Re: [Coco] CoCo3 to KV-1311CR Monitor cable.


> Here's Marty's document on his cable.  It doesn't contain a circuit
> diagram, unfortunately.  I did the modification inside the Sony to provide
> 5V to the Sony's connector, as suggested on the bottom of the third page.
> 
> https://drive.google.com/file/d/0B-q4dMVxT7u4bW1GdTJpSFVpcjQ/view?usp=sharing
> 
> Art
> 
> On Tue, Feb 10, 2015 at 2:41 PM, Stephen H. Fischer <
> SFischer1 at mindspring.com> wrote:
> 
>> A facebook user wants to connect his CoCo3 to a Sony KV-1311CR like I did
>> decades ago.
>> "Little" John speaks of a document that Marty Goodman posted somewhere but
>> I cannot find it. Marty appears to have built most of those cables sold.
>> -------------------------------------------------
>> I have three 76 ohm (Violet, Green, Black) resisters in the RGB lines
>> which cuts the voltage seen by the KV-1311CR in half.
>> A fourth resistor 50?? (Green, ???, Black) I believe is in series of the
>> output of the 74ALS02 sync combined IC.  I cannot tell the middle band.
>> -------------------------------------------------
>> Sony KV-1311CR inputs
>> RGB input: 0.7 V p-p, 75 ohms terminated
>> Composite sync input : 0.2 - 1.2 V p-p, 75 ohms terminated
>> -------------------------------------------------
>> I would like to give the user a link to the circuit, I just used my normal
>> method of looking at the data sheet and just doing the wiring may not work
>> for him.
>> Rainbow searches looking for the Good Doctors circuit have failed for me.
>>
>> TIA
>>
>> SHF
>>
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