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MCE2VGA with a PCjr

tempest

Veteran Member
Joined
Sep 16, 2014
Messages
930
Location
SE Michigan
My recent PCjr monitor troubles made me wonder if there was a way I could hook my PCjr up to my regular DOS/Windows setup and avoid having to rely on proprietary PCjr parts. Right now I have my PCjr with its own setup while my DOS/Windows systems are all hooked into a KVM and Audio selector and a nice 20" Sony Trinitron monitor. I'm able to stack the PCs and save a lot of space by not having to have a separate monitor/mouse/keyboard for each one. If I could somehow integrate my PCjr into that setup, I could really save space in my too small game room.

Up until now, that hasn't been possible due to the PCjr needing a proprietary keyboard and monitor which also doubled as the speakers. However I stumbled across a device called the MCE2VGA which is supposed convert all the classic graphics modes into VGA. I'm not sure how well it works with the PCjr, but it's supposed to work with Tandy graphics in addition to CGA so I can't see why it wouldn't work. Another issue is the non-standard PCjr video plug, but that can be overcome by getting a CGA breakout board or by using a homemade adapter (more on that later). The audio I believe can be tapped from the RCA jack on the back of the system and routed to a pair of speakers. Thankfully I already have a PS/2 to PCjr keyboard adapter so that's not an issue. With all these parts I *think* can hook the PCjr up to my KVM, but I have some questions:

1. Has anyone actually used the MCE2VGA with the PCjr? How well does it work?

2. If I use a PCjr to CGA adapter, will I still be able to get the Tandy/PCjr modes with a device such as the MCE2VGA? I assume the adapter is just a pin converter.

3. Speaking of CGA adapters, in a box of PCjr junk I got a long long time ago I found what appears to be a homemade CGA adapter cable. It has standard 18 pin PCjr display port plug on one end (two rows of 9) and what appears to be a CGA plug on the other end (two rows, top is 5 pins bottom is 4). At first I thought maybe it was a serial adapter, but the PCjr serial port appears to only have 16 pins. I assume that such adapters were a common place thing back in the day, but is there a simple way to test this? I don't have a CGA monitor to try it with, so maybe doing some continuity testing?
 
There was an original IBM adapter cable that allowed connecting a 5153 to a PCJr. There are quite a few on eBay right now.
 
There was an original IBM adapter cable that allowed connecting a 5153 to a PCJr. There are quite a few on eBay right now.

Yeah I think that's what I have. Maybe not the official one, but that's gotta be what it is.
 
2. If I use a PCjr to CGA adapter, will I still be able to get the Tandy/PCjr modes with a device such as the MCE2VGA? I assume the adapter is just a pin converter.
Yes you would, the austere CGA colour palette was a limitation of the CGA card, not the monitor. A CGA monitor itself was quite capable of displaying all 16 colours at once in graphics mode.
 
Good to know. I wish I could see some video of it working with a PCjr so I can decide if the quality of the video output is worth the price.
 
The MCE2VGA works well for its intended purpose, which is to connect to 4:3 VGA monitors and LCDs. It performs some rescaling, which may or may not be an issue (it bothers some people, others don't notice).
 
The MCE2VGA works well for its intended purpose, which is to connect to 4:3 VGA monitors and LCDs. It performs some rescaling, which may or may not be an issue (it bothers some people, others don't notice).

I don't suppose there are pictures to show what you're talking about are there?
 
The MCE2VGA works well for its intended purpose, which is to connect to 4:3 VGA monitors and LCDs. It performs some rescaling, which may or may not be an issue (it bothers some people, others don't notice).

I've been eyeing one of those for a while; long term planning right now. I can find Dell 17" 4:3 vga lcd monitors at the local thrift store easily, but the native resolution on those is 1280x1024. Divided by two, that gives 640x512 instead of 640x480. Is that what you're talking about? I've been thinking about getting one so I can drop a spare EGA card into a system, then use the converter to display faux EGA. Lord knows that's cheaper than finding a decent EGA monitor.
 
The adapter, at least what I saw when it was being developed, did these things:

- Discard overscan, to get a (line-doubled) 640x400 image
- Stretch that image to 640x480 to correct for aspect ratio on square-pixel LCDs

Many (most?) people who just want to hook up an LCD to see their computer work will not be bothered by this behavior.
 
The adapter, at least what I saw when it was being developed, did these things:

- Discard overscan, to get a (line-doubled) 640x400 image
- Stretch that image to 640x480 to correct for aspect ratio on square-pixel LCDs

Many (most?) people who just want to hook up an LCD to see their computer work will not be bothered by this behavior.

I use a real 20" CRT. Is this problem more noticeable on a CRT vs LCD?
 
The scaling is done by the MCE2VGA, so the extra lines would be visible on a CRT as well.

Better outputs are possible but they either cost more or require more work to assemble. For example, a gglabs CGA2RGB unit connected to an OSSC would provide a superior image. I am looking into assembling an RGB2HDMI (custom board + raspberry Pi) which promises a superior conversion as well.
 
The scaling is done by the MCE2VGA, so the extra lines would be visible on a CRT as well.

Better outputs are possible but they either cost more or require more work to assemble. For example, a gglabs CGA2RGB unit connected to an OSSC would provide a superior image. I am looking into assembling an RGB2HDMI (custom board + raspberry Pi) which promises a superior conversion as well.

Maybe I'll look into one of those then instead. OSSC is pricey though. I have a GBS-8200 from years back, could that be used instead of the OSSC with a CGA2RGB?
 
The custom firmware also requires adding a component.

The GBS-8200 is what I originally tested mine with. It's a terrible scaler; you get what you pay for (I paid $18). But it does work.
 
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