IBM 5175 PGA to VGA Conversion

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IBM 5175 PGA to VGA Conversion

Postby matpro » 2019-1-09 @ 07:44

Hi - I have an IBM 5175 that I'd like to convert to VGA and hook up to my IBM 5170. I've searched extensively and can find reference to a VGA modification being possible however no details of how to do it.

Does anyone here have any experience or knowledge on how to carry out the conversion? The VGA and PGA pinouts are similar, the major differences appear to be mechanical (DE15 v DE9) and PGD appears to have composite sync, instead of the separate H & V Sync in VGA.
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Re: IBM 5175 PGA to VGA Conversion

Postby matpro » 2019-1-09 @ 09:58

Thinking the below might work (converts the component sync signals into composite sync) but modified to output on DE9 as opposed to Scart.

http://www.nexusuk.org/projects/vga2scart/circuit
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Re: IBM 5175 PGA to VGA Conversion

Postby root42 » 2019-1-09 @ 10:07

Maybe this helps?

https://www.aceinnova.com/en/electronic ... r-circuit/

This will seperate composite sync back into H & V sync for VGA.
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Re: IBM 5175 PGA to VGA Conversion

Postby matpro » 2019-1-09 @ 10:36

Thanks, I'm planning on using the 5175 with a VGA card so the output will already be VGA / component sync, the 5175 however, requires the composite sync. PGA pinout below.

Image
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Re: IBM 5175 PGA to VGA Conversion

Postby root42 » 2019-1-09 @ 11:01

Oh, ok. I thought it was the other way around. Then I think you will want this instead:

http://www.epanorama.net/circuits/vga2rgbs.html
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Re: IBM 5175 PGA to VGA Conversion

Postby matpro » 2019-1-09 @ 11:25

That looks promising as well, a bit more complicated than the VGA to Scart circuit, will have to order some veroboard and components and start prototyping.
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