converting a tv chassis for arcade use.. Possible?

Started by phreak97, November 22, 2009, 01:08:50 AM

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phreak97

every crt tv converts back to rgb at some stage.. Is it really that difficult to chuck your own rgb in there at that point? Im not worried about losing the tv side of things, though id imagine you could put switches or something in. $100+ for a jomac chassis every time doesnt really suit me so well:p
I know it would be different for each tv, but an idea of what im looking for would be awesome.


papa_november

Certain very very old models of TV share tubes with certain classic-era arcade monitors, but that's about as related as they get.

You'll occasionally hear of people switching the tubes (it's the only real cure for burn-in) but the process is delicate and very tricky.

phreak97

I've also discovered jomac does a "universal" chassis which is really only semi universal, you have to tell him what resistances your yoke has and how many pins on the neck and he sets it up before it's sent off to you.
I think theyre a bit over a hundred bucks, I cant remember exactly, but it's a semi cost effective way of converting a tv into an arcade monitor.

southmonitor

#4
You will have to find the schematic of the TV set. Then find where the Chroma is separated into RGB signals to drive the tube cathodes. Insert you RGB signals in there and disconnect the input from the original TV circuit. Eliminate the Audio Amp, the RF Amp section, the Intermediate Frecuency section, Channel Selector and the Chroma Processor, you wont need them. The Monitor does not need nothing like that, it gets RGB signals and Vert and Horizontakl Sync ready, doesn't have to get them from the composite Video signal coming in modulated in a Radio Frecuency Signal. The Video comes in AM Modulation in Vestigial Single Side Band that has to be Amplified by the RF Amp. and the IF AMP, then demodulated. The Choroma signal comes there too encoded in the Video, is a tremendous headache that Monitors don't need. They get it ready. Find where the sync separator for your TV ends in the schematic and there you will have to inject the sync signal for the new RGB signal you are trying to view. Beware of the sync polarity. Also note that the TV set could only be used for Low Resolution applications since all analog old TV sets are 15KHz Horizontal Frec at least on NTSC norm (USA). It's going to be a tough job and time consuming, no mention that you have to have extensive Electronic knowledge to do it yourself. Better to get a new or used monitor and use all that time and effort for a better cause.

RGB32E

#5
Quote from: phreak97 on January 10, 2010, 11:02:06 PM
I've also discovered jomac does a "universal" chassis which is really only semi universal, you have to tell him what resistances your yoke has and how many pins on the neck and he sets it up before it's sent off to you.
I think theyre a bit over a hundred bucks, I cant remember exactly, but it's a semi cost effective way of converting a tv into an arcade monitor.

What's wrong with a real arcade monitor, you know... that's intended for games? ;)  Building an arcade monitor from a crappy TV is pointless, especially when you can purchase an arcade monitor.

NFG

Often times people will have more time and tools than money.  Why buy when you can sink a few evenings into making your own?

That said, I've found that unless you're buying a relatively new and expensive arcade monitor, the quality is usually lower than a decent consumer tube.  It was always super disappointing to me when, after spending weeks getting RGB sorted out on an arcade monitor (in this case a brand new 21" Wells Gardner), it'd look like crap compared to my JVC TV using Svideo.

phreak97

Quote from: Lawrence on January 20, 2010, 10:56:25 AM
Often times people will have more time and tools than money.  Why buy when you can sink a few evenings into making your own?

That said, I've found that unless you're buying a relatively new and expensive arcade monitor, the quality is usually lower than a decent consumer tube.  It was always super disappointing to me when, after spending weeks getting RGB sorted out on an arcade monitor (in this case a brand new 21" Wells Gardner), it'd look like crap compared to my JVC TV using Svideo.

yep, thats why. new arcade monitors are very expensive and are made to quite a low standard these days anyway.. theres hundreds of crt tv's going free or cheap since flat panels became the norm. I drove past three on the way home from work today.

plus it's all about the DIY

RGB32E

Quote from: Lawrence on January 20, 2010, 10:56:25 AM
Often times people will have more time and tools than money.  Why buy when you can sink a few evenings into making your own?

That said, I've found that unless you're buying a relatively new and expensive arcade monitor, the quality is usually lower than a decent consumer tube.  It was always super disappointing to me when, after spending weeks getting RGB sorted out on an arcade monitor (in this case a brand new 21" Wells Gardner), it'd look like crap compared to my JVC TV using Svideo.

Hmm... that makes sense.  I guess I've been spoiled by my PVM-2030 for years! ;)  It does a great job with both arcade RGB and console RGB.  I've noticed some threads out there that seem to indicate that the quality of WG monitors have gone to the crapper over the past decade.  I'd still like to get a PVM-2950Q in good condition!

Speaking of the PVM-2950Q, user eastbayarb took a perfectly good PVM-2950Q, gutted it to put in a cab, and cracked the tube on installation!  :'(  :D  What a waste of a completely good monitor!

RGB32E

Quote from: phreak97 on January 20, 2010, 01:00:24 PM
yep, thats why. new arcade monitors are very expensive and are made to quite a low standard these days anyway.. theres hundreds of crt tv's going free or cheap since flat panels became the norm. I drove past three on the way home from work today.

plus it's all about the DIY

What do you think about the quality of those TVs?  Before flat panel TVs, there was always a quality difference between makes and models of CRTs, and how much use they've had.

Have you acquired any used CRT TVs worth modding? 

I've picked up "ready to go" PVMs for around $50, RGB ready to go, and a nice aperture grill screen!  The newer PVMs had a much darker coating for better contrast, and the PVM-2950Q has a super trinitron tube... just like my 32" XBR100.