Is it possible to bypass digital processing on a consumer HD CRT?

Hey all! I'm sure this has been asked multiple times before but I can't seem to find a definitive yes/no answer. As an electronics novice (like really novice), I'm not sure if the title is completely accurate either. I am also going by what I am told so if I am wrong on anything, I apologize and I ask for me to be corrected.

So we all know how consumer grade HD CRTs upscale 240p/480i content and process all content digitally much like an LCD. This results in all sorts of issues like 240p being treated as 480i and of course the biggest of all: broken light gun support (which can be corrected with the LCDZapper kit).

The PVM-14L5/20L5, BVM A series, and BVM D series professional and broadcast grade HD CRTs do not have this kind of processing and do not upscale. This means everything is displayed as it should be and light guns still work.

Seeing as the PVMs and BVMs mentioned above are expensive (some being $5K+!), is it possible at all to actually bypass the crap in consumer HD CRTs to essentially turn them into cheaper HD PVMs/BVMs?

I'm asking because my great grandmother has a 32 inch 16:9 Sony Trinitron HD CRT she is willing to give me... assuming I can get it out of the basement... anywho, it would be much nicer to just modify that than spend $3K+ on a 16:9 BVM that can do HD.

 

light guns don't work because of 100+Hz deflection. yes! you can bypass. in some cases the MCU board uses component signals as output, you must just trick the muxer.

 

Take the TV regardless, they are nice sets. Make sure you bring a strong friend though.. It was a serious grunt for 2 people to move my 34"

The possibilities of bypassing the processing sounds very intriguing. While I mostly don't have issues with any of it, the one system that could see improvement on my setup would be the SNES. I would assume that this would be an invasive mod that would make it an all or nothing result but still am curious how one would do it.

 

in some cases you can turn off MCU postprocessing through service menu like i did on my trinitron kv-32fx60d.

 

Interesting... Would that require cutting traces for the MCU's outputs and soldering to the next part in the chain or the traces directly (after disconnecting those output lines)?

I wonder if my great grandmother's HD CRT's service menu can be easily accessed. Will this disable all digital processing and upscaling? As in 240p will be displayed correctly like any SD CRT along with the other modes including HD? If so, I might just do that and call it a day.

It'll take more than that... it took six people to get it into her basement when she bought it brand new. Not to mention it is in rural Misery Missouri and it needs to go 840 something miles southeast to Florida. It'll be very expensive getting it here.

Yes, what we're talking about is bypassing internal circuitry. Almost like a SD CRT RGB mod if I had to compare.

If this mod can be done, whether through hardware or software, it would be worth the drive (which is worth it anyway since I get to see family).

 

Oh really? I'll look into that, mine is the KD-34XS955N.

Oh, didn't realize it was that far of a drive. Me and a friend managed to get mine home, but it was only a 40 minute drive away.

 

In general, those consumer grade CRTs are fixed-frequency displays with a digital scan converter. It may be possible to disable the digital processing, but if you do that then the only format the display will be able to handle is whatever the native display format is - and in a lot of cases, especially with wide-screen CRTs, that native format is 120Hz, so no normal video format will be supported.

For example, in the case of the Sony TVs, if it has "Hi-Scan" as one of the marketing features then it's a 120Hz display - and you probably won't be able to disable the scan converter at all.

 

Unfortunately, I can't tell you whether or not an internal mod of the CRT is possible or practical. I do suggest, however, just looking around locally on apps like OfferUp for a free Sony CRT, rather than travelling to get a particularly heavy one. A 27" Sony CRT weighs around 100 lbs and can usually be handled by one person, whereas the 32" and up models are easily 200-250lbs or more and require a minimum of 2 people to move.

I myself have the KV-27FV310, which is hard to find but also produces an outstanding picture when properly tweaked. As others have stated, most times, a careful exploration of the service menu options will often times be enough to give you the types of picture adjustments that you're looking for.

Although, I can tell you from experience, I had a 32" Sony XBR CRT before my current model, and it had some features that you were unable to turn off, except when in "Movie" mode, even . Only in Movie mode was I able to get the sharpness correct, but unfortunately I was unable to get the correct color. So I ended up giving that TV to a family member who wanted it for casual viewing.

 

On the 34XBR960, there is a service mode called HDPT (HD Pass-through) you can enable to completely turn off digital processing. This eliminates all lag. However, with this mode enabled, you can only display a component video image at the TV's native resolution (480p or 1080i). All other modes will not display.

HDPT is not an option on some XS955 models.