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Fault with TPI-PRO

I've just received, via Ebay, a TPI-PRO-4. It works quite nicely, but I've found that one of the inputs, when fed with a VGA signal from a Windows 10 PC, has 'sparklies' on the picture. Feeding it with a VGA signal from an Apple Mac is even worse. I haven't tried it with an S-Video yet (which will be it's ultimate input).

So, does anyone know what might be wrong? I'm not adversed to popping the top off and looking to fix it, I just need some pointers as to what to look for.

I've also found that it 'forgot' my calibration settings when it was powered off for about an hour. When I did re-calibrate it, it appeared to crash (i.e. no touches on the screen would do anything). Is this a sign of another issue developing?

Also, while on the subject of S-Video into these - there are a few VGA to S-Video and RCA cables on Ebay but I'm not sure how they are wired...just that they are designed for those PC graphics cards which have the TV out option. I was just going to buy a S-Video connector and wire up my own, as I've got plenty of 15 way D-Type connectors.


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    I've now received a perfectly working TPI-PRO-2, which I purchased with the intention of fixing the TPI-PRO-4. But, the chips are surface mounted...so, should I risk it and use the TPI-PRO-2 to fix the TPI-PRO-4, and maybe end up with 2 faulty units...but, on the other hand have a working TPI-PRO-4; or leave them both as is?

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    I've had a thought about daisy chaining the two (as the unit has a pass-through facility). So I arrange the TP4 design on the 4 port unit to not use input 2, and allow pass through touches on input 4. Input 4 has the 2 port unit connected, with the TP4 design suitably configured.
    At the moment, the 4 port unit has the four inputs arranged as a 2x2 grid. When one of the inputs is touched, it goes full screen. Touching again, makes it shrink back. All this without a Master (which is only used to program the units).
    I'll have a play and report back.

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    John NagyJohn Nagy Posts: 1,736

    Sounding like a setup for a Netflix sci/horror movie.

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    Yep, you're probably right. But no doubt easier than trying to swap over a surface mount IC in the hope that it is where the fault lies, and the working one does not get damaged during the desoldering process.

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    John NagyJohn Nagy Posts: 1,736
    edited January 2020

    Still, like rigging a '71 Vega to tow your '61 American because the the Chevy has no brakes, and the Rambler won't start. Even if you can, should you?

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    You've lost me with that reference.

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    ericmedleyericmedley Posts: 4,177

    John's quip is saying that you are spending an awful lot of mental energy and time on what is clearly a 'hobby' project on very antiquated equipment that has a very limited parts supply and even less support. Many of us oldsters on the forum suffered long with the TPI trying to get it to work with all the crappy video cards and whatnot available at the time.

    My opinion of the whole thing was it was a semi-good idea that in practice was not worth the effort it took to get it to about an 80 percent reliability.

    I'm not saying that you should not do this thing as I too am kind of a hobbyist. I have a lot of old crap that I still use and tinker with all the time. But one must keep in mind that it's kind of difficult to get others to be as interested in your hobbies. Hobbies, by their very nature, are lonely pursuits.


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    Yep, fair point.

    I only got the TPIs because I had an ELO touchscreen doing nothing, and then saw, in a client's room, a TPI-PRO-2-DVI, which got me wondering. So I found one and bought it to tinker with, and breath some life into my touchscreen...and also get another monitor which I can connect my retro computers up to (suits the Commodore 64 really well, but not so much the BBC Micro...this needs an extra video adapter).

    I'm also using it as a training tool, as I never know what I might find at clients' sites and, being a support engineer, this knowledge might just come in useful. And, hence, I like to pass this knowledge onto others. In fact, the main reason why I begun buying old AMX kit was to learn. I'm also doing training on Extron and Crestron gear too (but their kit is a bit more expensive and, in my opinion, not as good).

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    OK, for what it is worth, I've rigged them up, daisy chained and changed the projects for each to suit (with a USB pass through to the second one). Works quite well, but it needs two taps on the daisy-chained buttons to bring it to full screen (i.e. input 1 on the TPI-2, which is fed into input 4 on the TPI-4).

    Think I might need to introduce some logic from the Master.

    And, there, this ends this topic.

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