cable adapter needed

[newTIboyRob]

Hello all. I have the white C64 and found I had the composite video cable for use with a modern flat screen monitor, (cable with din on one end for the back of the C64 ending with RCA red, white audio and yellow video cable on other end.)  Problem is, the back of the monitor has its own cable plugged in fine, and no RCA jacks. The end of its cable is show in the photo.  Is there an adapter that will take the end of the cable shown to accept the red white and yellow RCA ends of the composite cable?  If anyone knows, please send me the link.

Thanks!

[carlsson]

Short answer: No.

 

Long answer: There may be a series of steps involving fairly expensive adapters, with loss of picture quality. Essentially what you have is a VGA monitor intended for a PC. The majority of these accept a sync frequency at 31 kHz and upwards, while the C64 outputs only 15 kHz. Also VGA is an analog RGB format, meaning the signal is split into components of red, green and blue while the C64 outputs either composite video (a single signal) or a signal split into luma (lightness) and chroma (colour signal, combined). If - and only if - your VGA monitor would be among those 1-5% of monitors that really accept a 15 kHz signal, you could connect the luma signal to one or more of the pins to get a monochromatic image, but that most probably is not what you want.

 

There are adapters like composite to VGA or composite to HDMI at various price ranges, but those need to convert the signal on the fly which may introduce a certain amount of lag (delay) plus that there may be loss of quality in the conversion as those devices are generic. Generally you get what you pay for, a device at $30 might satisfy the most casual gamer, many others are looking at devices at $100+ just to get something useful.

 

Your cable sounds like it is wired for chroma + luma on a Commodore CRT monitor. I think you are better off trying to find another LCD/TFT monitor, or even try to find an old CRT with composite or S-Video inputs. You might find that you need a different video cable in the end depending on exactly where you end up, but the monitor you are trying to connect will likely give you a fair bit of headache. Feel free to post a model number of the monitor for better figuring out its specs and capacities.

[newTIboyRob]

wow, your answer was really impressive... thank you.  Darn, ok.  I actually did what you said... I found an older flat monitor with the red and white RCA audio and yellow video RCA jack.  It didn't have its power adapter and since I bought it used at a rummage sale, I was debating whether I wanted to gamble the $15 for its adapter, knowing perhaps that it still may not work.

 

Maybe that isn't such a bad idea to roll the dice with that after all, considering the alternative!

[newTIboyRob]

By the way, the monitor is  the Magnavox 15" LCD HDTV Monitor 15mf400t/37 which takes a 12 v plug.

The one I found was actually $12 + tax.  Is there an even cheaper generic 12v adapter plug that will suffice?  

[carlsson]

The curiosity here is that the flat screen monitor you mention most likely accepts composite video (yellow) and stereo audio (red and white) while the Commodore 17xx, 18xx, 19xx, 108x monitors use yellow for composite/luma, white for mono audio and red for chroma. It means if you plug in your existing cable into the monitor you found, you might end up with noise in one of the speakers and a greyscale or very weak colour image. If you get another video cable wired to use composite video instead, you'll have two RCA plugs instead of three, of which one goes to yellow (composite video) and the other is mono audio. Some people like to split the mono audio into two inputs, but there is kind of a standard that says if you only plug a signal into one of two inputs (left one IIRC), the TV/stereo etc will treat it as a mono signal and broadcast it through both speakers.

 

On your second question about the Magnavox monitor, it seems to draw up to 50W per official specs. Many of the 3rd party power adapters I find are rated 12V 4A (= 48W) or even 5A (= 60W). The key here is that voltage should always match as close as possible, and the ampere is a minimum, i.e. you can't use a 12V 1A adapter on a monitor that requires 12V 4A, but vice versa would be fine. If you are lucky, you might find some at a second hand store for less than what those 3rd party adapters cost online, but the more ampere you need, the harder it can be to find it.

 

In theory you could use an older PC power supply, in particular the AT type (286 to Pentium, before the ATX generation). Those power supplies tend to offer quite a number of ampere on the 12V line, but I don't know how well they behave without load on the other lines like 5V. Also it would involve some DIY to go from one of the Molex connectors to a DC barrel jack - with wiring it up for correct polarity so you don't burn the monitor - so it depends how qualified you feel you are regarding low voltage electronics, soldering, isolating etc. It also assumes you'd have or easily could get access to a such power supply.

 

 

[newTIboyRob]

Hi there.. so after thinking about it, knowing my lack of knowledge and comfort level with soldering, isolating, etc. it sounds like a replacement plug is the way I would be going with this. After all, it's not a lot of money, heck I have spent more than that on what turned out to be a bad sandwich!

 

Thanks for you help carlsson!

[carlsson]

As a fun side fact, the VDC chip in the C128 which handles the separate 80 column output, is quite programmable for customization so there are a few hacks where it is cranked to produce a 31 kHz image which means with the right, passive cable it could be used with a VGA monitor but only for those particular non-standard video modes. Normally it operates at 15 kHz as well, generating something more like a CGA display.