Revisiting the Sony BVM 20F1: BKM-21D no colour fix, operation hours, & transcoding composite to RGB
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- Опубліковано 15 лип 2024
- The Sony BVM 20F1 is a top contender to be the king of all 4:3 standard def CRT’s. I had recapped and calibrated the monitor before tucking it away into storage, and have since enjoyed gaming on a widescreen CRT. But a high end consumer CRT doesn’t match the sharpness and accuracy of this 900TVL Broadcast Video Monitor.
I pulled the monitor out to find it inconsistently displays PAL 60Hz in full colour via the BKM-21D addon card. While capacitors were on order, I also went on a composite to RGB transcoding venture to bypass the BVM’s malfunctioning composite video board.
After going down the transcoding rabbit hole, and with advice from Savon Pat, I recapped the BKM-21D to have clean composite video in PAL 60Hz. Attached below is the link to the cap list.
Most topics covered should also be applicable to the BVM 14F1 and other monitors that also accept the BKM 21-D option card such as the BVM D20F1. The 20F1 suffix differs depending on region eg. 20F1U (US,) 20F1E (Europe), 20F1A (Australia), 20F1J (Japan). Other topics include degaussing, operation hours in standby, auto calibrating to SMPTE colour bars without the BKM 14L probe, 75ohm termination and firmware revisions.
Transcoders tested:
- Sony YR-421 S-video to RGB through JP21 (converted to Euro-Scart)
- Extron CD 900 composite and S-Video to component and RGB (RBGs, RGsB, RGBHV, YPbPr via BNC)
- OSSC Add-on board composite and S-Video to component and RGB (YPbPr through RCA and RGB through Scart)
- ODV composite, S-Video and component to HDMI (externally converted from digital to analog with an HDMI to VGA converter to RGBHV, then passively combined sync to RGBs via scart). Link to sync combiner write-up from Bob: www.retrorgb.com/building-a-p...
The transcoding segment is a prime example of what happens when a company clones a product and calls it their own. Buy from the original creators:
Retrotink 2x Pro
www.retrotink.com/product-pag...
A warning that working on a CRT can be dangerous and if not lethal. You should not attempt to open up or fix anything IT without having good understanding of safety precautions. I am not responsible for any harm or damage done to anyone or anything. After all, this video is just a video diary of my progress. And if you have epilepsy or photo sensitivity, I do not recommend you watch this video. 
#crt #retrogaming #pvm #crtgaming #trinitron #transcoding #tvrepair #soldering #sony
Links
Original BVM 20F1 recap and upgrade video
• Sony BVM 20F1 Recap an...
BKM 21-D capacitor list
docs.google.com/file/d/1z6kIQ...
Sony BVM 20F1 operation and service manual
archive.org/details/SonyBVM14...
F series BVM firmware
arcadehacker.blogspot.com/2019...
Credits
RetroRGB
/ @retrorgb
Sony YR-421 analysis
ua-cam.com/users/livefkHl-nw2...
Interview with Phonedork, brief discussion of the BKM 14L probe
• RetroRGB Weekly Roundu...
Zez Retro
/ @zezretro
Sony YR-421 review
• The one of a kind S-Vi...
Wren Tubes
/ @wrentubes1886
Degaussing using a drill
• CRT Degaussing With A ...
Andrew One Man Band
/ @andrewonemanband
Bob Ross Joy of painting cover
• Bob Ross: The Joy of P...
00:00 Intro
03:30 Testing operation hours
05:50 Auto calibrating
07:52 BKM-21D composite video
10:52 Transcoding composite to RGB
19:34 Recapping the BKM 21-D
21:54 Summary - Ігри
A little more info about the auto preset calibration, as far as I know it only affects the colour voltage levels, not the colour temperature controls, and as such it should be ran before calibrating white balance with a colorimeter. You can see what it affects in Maintenance → Setup (but be warned, going into the setup menu will set the phase, chroma, brightness and contrast values in the user preset menu back to 1000). For the autocalibration process itself, the monitor expects full field colour bars from a reference pattern generator. I've had good luck on all of my BVMs with my LT-448 pattern generator, Wii YPbPr is probably the closest you can get to that with consumer equipment. Also, as you can see in the setup menu, there's independent controls for RGB, YPbPr, composite and a few others, so I always make sure to run the auto calibration on RGB and YPbPr separately to make sure they're all set up correctly. btw, I think there's a couple of reasons the MiSTer doesn't work very well for this : the 240p test suite itself doesn't output reference quality colour bars on original hardware on any console as far as I know, but the MiSTer accentuates this by having large issues with its analog output. Depending on the I/O board you use, the voltage levels can be way off (the official one is the worst, it can vary by ~±100mv, which is a lot considering the standard for analog video is 700mv on a full white screen). The retrocastle I/O board is actually almost perfectly on spec, and it's great for RGBs output, but it still suffers from inherent issues with RGsB (sync on green) and YPbPr output. RGsB has a large green deficiency (it was reading 750mv on red, 870mv on green, and 750mv on blue, it should be 700mv, 1000mv and 700mv respectively), and while YPbPr has the correct colour voltages relative to each other, it's 60% lower than it should be (on my calibrated 20F1, reference reads 100 nits at 100 IRE, but the MiSTer was reading 60 nits). Hopefully this information helps somebody out :)
Thank you for the super informative explanation. Makes sense that my ‘offical’ IO board was causing the 100 IRE error if the RGB voltage can vary above 700mv. I’ve pinned your comment, thanks again
Very interesting video, many thanks 😉
Always wanted to understand TV better, especially Analogue TVs, just never got round to it. ✌🏽
What would you say are the best learning books you have read on this subject? ✌🏽
very cool story!
Loved the chill intro. I had a lot to say about PAL that would probably make many people angry and prompt the superior colors, RGB SCART availability and America=Satan responses, but as far as gaming, and for a lot of things I personally want to do, such as playing my intros and breaks on VHS while on stream, it has been the bane of my freaking existence, and I have grown an almost irrational disdain and hatred for it over the years. In addition to consoles and even CRTs, I now need to import VHS players from back home as well, to do the stuff I need. Granted, I chose to move here, so it is what it is.
But onto more positive things, have you ever seen or heard of the BVM-1911 (BVM-2011P in Europe)? It's also 900TVL and reminds me a bit of your pride and joy there, just older. I managed to get one, and out of my 30 plus CRTs at this point, it is my damn favorite. The only reason I haven't made a playthrough video on it yet is because I will have to carry it to the shed, where I record my videos and do my streams, and man, that's a good deterrent. Loved the video as usual, great job. PS edit: beautiful dog at the end.
PAL was fine growing up because we didn't know any different but when you get a taste of the 60Hz, then you see we were short changed. I've seen the BVM 1911, not in person but another CRT youtuber has featured and it's essentially the pre-cursor to the 20F1 with those manual dials tucked away in the pull-out drawer. My friend had the earlier 600TVL model and even that looked crisp up close. But man are they heavy! Thanks again for the reply, Ciccio at the end is the most placid and well natured dog I've met, just beautiful.
@@MarcoRetro316 Yes, I did meet a lot of Europeans that got to hate PAL after they learned what happened. A mass reaction to that was when Nintendo decided to use 50Hz games for their Wii U Virtual Console, prompting a very negative reaction from many European gamers and a lot of news articles. They probably just thought that since the people grew up with it, it's what they would want, but turns out by then a lot of them had wised up.
As for the 1911/2011P, I'm debating bring it to the shed today for the next stream/video. The drawer, man. It is the best. I can't stress that enough - no menu, no nothing. A little screwdriver and you can adjust everything. It even has its own grid you can turn on to check geometry, and then many dials to adjust every bit of the screen individually. If I had to choose only one of my CRTs to keep, that would be it. It is very sharp, but I would say the one downside is the very reflective screen, as with most of those older sets, so it likes the dark, and yep, that weight!
I've also had the same difficulty trying to run the auto calibration on my D20F1U. It's comforting to see someone else having the same issues on a similar set. I was worried something was wrong with my set.
I’ve read that the monitor wants exact video timings and position of the colour bars. Makes sense that I nearly got there by turning on interlacing in the Genesis test suite. It’s probably looking for a pattern generator SMPTE image which would be interlaced and a solid 60Hz.
Loving your videos, very well made and informative. I just ordered a BVM-20F1U and its currently in freight delivery. I'll be looking to your channel for some guidance, its also recently been recapped and calibrated by SavonPat
Thank you! If it helps someone then documenting my journey has been worth it. The best and worst thing about a BVM are all the tuning options and you can find yourself getting lost in fixing a tiny imperfection instead of enjoying the video content. Good thing that it’s recapped and serviced so hopefully it’s running at its peak potential. Congrats!
Yep I once heard a PVM owner say the best and worst thing about these units is the 240p test suite. Oh and btw I was laughing in NTSC 😂
🤣🇺🇸🤣
While I haven't attempted this yet, I did pick up a used colourmunki photo a few years back for CRT calibration. Its a spectrophotometer as opposed to a colorimeter, so hopefully wont be subject to the shortcomings of ageing colorimeter filters.
Most of the calibration and repairs are part of the fun that makes up the hobby and you’ll come out learning lots in the end. I’m very novice in colorimetry but I hope you get it all dialled in. RetroTech USA’s discord via Patreon has very helpful members if you get stuck as well as ConsoleMods.org discord server.
Wow quality footage of them scanlines. wats ur secret?
I’m super amateur in recording footage tbh and just using an iPhone XR with the single camera. 60Hz footage is filmed with the stock camera whereas 50Hz with a subscription app Filmic. It’s a combination of putting the camera close enough to the CRT that you capture more field of view than necessary, then zoom a little to the area of interest which lessens the moire artefact. A dark room helps quiet a bit otherwise I found the camera would focus on the grill rather than the whole image on screen. I lock the focus once I’m happy with it and I make sure the CRT’s brightness and contrast aren’t too high which tends to was out the colours
Hey sorry to ask here like that but I have an Sony BVM but the picture collapsed and I dont know where to start faultfinding on the unit
When you say collapsed, you mean there's still a raster but it's compressed to only 1 line either horizonal or vertical? If so then it's a fault in the deflection circuit, depending if it's horizontal or vertical then that should point you to which area of the board to test or troubleshot. On the BVM 20F1 the deflection card is the 'D' board which has the large heat sinks.
I've got a BVM-14H5A and PVM-14L5A, PVM-20L5J. I find the BVM to be much more fussy about inputs than my PVMs. It is just weird behaviour, where as I can just connect anything and everything to my PVMs and they display fine. One of the reaons I never use my BVM, really should move that guy on.
My setup is full component for convience, no switching inputs or changing settings it is sweet.
I here ya, they’re definitely fickled and not as straight forward as a PVM, especially with the D14H5 being picky with sync. If you’re not into the easier maintenance or calibration side that a BVM offers then I’d go with the L5 any day.
Once an auto switching setup is all running it’s seriously worth it! Love just turning on any console and seeing it display on screen
Video editing on PowerPoint? Pfffft, real men edit straight up with FFmpeg writing every parameter on the command line.
😆🤣🤣