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Toshiba - Sega projector... help ? o.o


Rattanee

Question

So I have these two Sega Megalo 50" projector sitdowns... of course the CRTs were burnt to hell and back on both... fresnels cracked and whatnot... so recently I got a 50" Pioneer RPTV that had a dud flyback... bought if for $50... fresnel flawless... basically that was the only reason I bought it... broke it down for parts and did away with it's box.

 

Now I managed to find out that tubes in it are pin-compatible with the original Toshiba tubes, so of course after a year of storage, the Hitachi CRTs that came from the Pioneer TV came out... drained them, disassembled, cleaned, then proceeded to replace the Toshiba CRTs with them... horribly tedious work...

 

After I cleaned all the lenses etc, assembled the thing, and turned it on... it fired up fine, then a few moments in POP... like an exploding component... or HV arcing... but saw no lightning and it was a one-time occurrence... that was when I noticed I had left the yoke connector of the green CRT dangling... BLARGH... (mental note, next time don't work into the AM)

 

So I plugged that back in, powered it on hoping it survived, and it actually fired up... granted it'll need a lot of adjustment... I set about doing the mechanical focus, then electronic, and again I heard a loud pop... same as before... except this time it left me with the right edge of the image missing, moreso on the green tube then the red and blue... any ideas what I fried?

 

Really not looking forward to this as the G2 from the flyback to the distributor is hard-wired... and I don't like snipping high voltage cables... real shame as the image never looked better...

 

Also, anyone know if silicone-sealing the CRT anodes in is necessary? Come to think of it... the loud pop could've been HV arcing to DAG... or a scary though... the yoke?... o.o uhh...

 

It's the notoriously un-identifiable Toshiba projector sega used...

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Your too keen... wouldn't be easier to dump them and use LCD/LED monitors.... ?

Easier, yes. Looking better, or even authentic? No... LCD/LED just look fuzzy at anything other then their native resolution, plus I'm using it as an EGA monitor, which isn't even supported by any LCD/LED TV natively, and I'm definitely not using the cheapo scan converters... the jitter every other second when the frequencies cross makes me want to gouge my eyes out with a teaspoon.... just personal opinion, but no way in hell am I converting -any- game to LCD -ever-.

 

You said you "drained them" (CRT tubes) I take it you mean you drained the lens coolant...But did you refill them??

Of course. Filtered the coolant and reused it. One of the tubes had the coolant smelling rather funky... that one I tossed and added from what I drained from the Pioneer Assemblies.

 

The problem is definitely on the deflection and video bd assy. I moved the board combo over to my working projector and it generates the same fault.

 

It's as if beam power is missing at the beginning of scan... I took my time yesterday and pulled the defl board for inspection, found nothing obviously blown. Few poly caps measured lower then their nominal values, but everything else seems to be in order... I have to dig through the hundreds of tiny resistors and capacitors next I'm guessing... First I'm going to try swapping flybacks though, just to be on the safe side. If the flyback went, I'm tempted to just send the thing rolling down the hillside....

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Here's a pic of the current problem...

 

Anyone has any idea which circuit could be busted? If I move the H-position to the left, what is missing from the right side does appear. If I roll it to the right, more of the picture vanishes.

 

Edit: Bah... where'd the pic go...

megaloprob.jpg

Edited by Rattanee
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Side-note-addition:

I eliminated the flyback. I swapped it over to my working chassis, and put it into this set.

 

Here are the tubes that came out of the set originally:

Blue:

blucrt.jpg

Red:

rdcrt.jpg

Green:

gncrt.jpg

And here is the picture as it originally was:

hunt.jpg

Barely any green, blue had horrible black holes in the image, along with some in red.

 

Here is the picture with the old flyback but the working chassis:

fullscan.jpg

 

And here it is with the set more or less properly adjusted with the replaced tubes (still need some time to fine-tune the convergence... plus the convergence ICs have not been on for more then 3-4 hours total so they need to burn-in anyways before I can do a final convergence setup that won't change):

adjsted.jpg

 

 

So basically... I'm looking for a deflection board failure that involves having had the horizontal and vertical circuits under-loaded, and would cause half of the screen to go black... Anyone any ideas?

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Even the red is quite abit worn!! Its not real common to see that, although my NEC XG had a burned red in it when i got it. The Sony i have here had done abit over 60,000 hours and all 3 tubes were toasty brown, although the red isnt too bad. Soft as hell though being ES focusing tubes. The NECs are all EM focus and sharp as a tack even when theyre worn too uneven to use.

 

Yes you should be using silicone on the anode caps, and let it fully cure before you turn it on, or itll quite likely arc there. I skipped that step on a Sony front projection CRT i retubed a couple years ago and it arced, then i siliconed and fired up almost straight away after assembly and it arced, had to redo the lot and wait, its never arced since.

 

 

Your too keen... wouldn't be easier to dump them and use LCD/LED monitors.... ?

Where does one find a 50 inch 4:3 LCD monitor? You could use a 16:9 if you didnt care that its gonna look stupid, but really, why would anyone really want that? Only way youd get around it is use a 4:3 LCD projector and hope it will fill the screen properly from inside the original rear projection cabinet.

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Cheers mate ;) i havent ever needed any more yet, i would imagine itd be quite simular to the glycol used in chiller plate systems and post mix pumps, although ive never seen a bottle of the stuff you have there to compare. If it is the same i can get that quite easily.

 

The Sony CRT projectors i have here use tinted glycol in the red and green, a few 7" projectors used those same Sony 07MS tubes. Notorious for getting "fungus" although its never happened to me. The NECs have an issue on their 8" air coupled tubes where they suck moisture into their glycol, eventually building up reasonably high pressure and either cracking the glass or imploding the tube.

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Even the red is quite abit worn!! Its not real common to see that, although my NEC XG had a burned red in it when i got it. The Sony i have here had done abit over 60,000 hours and all 3 tubes were toasty brown, although the red isnt too bad. Soft as hell though being ES focusing tubes. The NECs are all EM focus and sharp as a tack even when theyre worn too uneven to use.

 

Yes you should be using silicone on the anode caps, and let it fully cure before you turn it on, or itll quite likely arc there. I skipped that step on a Sony front projection CRT i retubed a couple years ago and it arced, then i siliconed and fired up almost straight away after assembly and it arced, had to redo the lot and wait, its never arced since.

 

 

 

Where does one find a 50 inch 4:3 LCD monitor? You could use a 16:9 if you didnt care that its gonna look stupid, but really, why would anyone really want that? Only way youd get around it is use a 4:3 LCD projector and hope it will fill the screen properly from inside the original rear projection cabinet.

 

You would be surprised. Most people dont even notice the difference as they are too busy drooling over the picture quality compared to their old flogged out rear pro.

 

I watched one of these go in a line up to be skipped because the screen is rooted..Seats where a littke different.. Would you lcd this to save it ?? I considered it but large stuff is hard to sell.At some stage you are going ot have no choice if you want to keep some of this from ending up junk..

 

http://i273.photobucket.com/albums/jj214/rikitheshadow/SNK%20Neo%2050/Original.jpg

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@Gameworx I agree with you there, large stuff is hard to sell, mostly due to difficulty of moving it and space to store it.

 

I have at least one, if not two CRT projectors here that digital simply cant touch for picture quality, even at 1920x1080. So ill stick with the pixel perfect image and extreme contrast ratio of projection CRT any day of the week ;)

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I would've bought that even with a dud screen... except I'm not in Aus... At one point I had four of these projection beasts.

 

You would be surprised. Most people dont even notice the difference as they are too busy drooling over the picture quality compared to their old flogged out rear pro.

 

I watched one of these go in a line up to be skipped because the screen is rooted..Seats where a littke different.. Would you lcd this to save it ?? I considered it but large stuff is hard to sell.At some stage you are going ot have no choice if you want to keep some of this from ending up junk..

 

http://i273.photobucket.com/albums/jj214/rikitheshadow/SNK%20Neo%2050/Original.jpg

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@Gameworx, i wouldnt LCD any rear projection CRT unless it was installing a 4:3 LCD projector that is 15.75kHz capable and retaining the original display surface. That way it would still appear somewhat normal looking ( correct aspect ratio is pretty important to me, which is why i have adjustable blanking curtains on my 125" 5:4 screen, i never have bands at the top and bottom or sides of my screen, whether its 5:4, 4:3, 16:9, or 2.35:1 )

 

Id sooner fix the CRT and enjoy the substantially better image they can provide when correctly calibrated. Believe me, there is loads of suitable CRT projection donors out there and its not hard to make them fit if youre serious about having the best ;) ( which LCD will never be cause it still cant do black like a CRT can )

 

But i wouldnt be suprised people with no real knowledge on how it CAN look would think an LCD with an incorrect aspect ratio looks better than a properly calibrated CRT. People generally think we have moved forward when we went to digital. If only they knew what a top end CRT can do when set up right, theyd wipe the drool from their chins after they pick them up off the floor and drop the LCDs and DLPs like a hot rock.

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