Revisiting the Sony BVM 20F1: BKM-21D no colour fix, operation hours, & transcoding composite to RGB

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: https://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
https://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 and Upgrade AKA S...  

BKM 21-D capacitor list
https://docs.google.com/file/d/1z6kIQ...

Sony BVM 20F1 operation and service manual
https://archive.org/details/SonyBVM14...

F series BVM firmware
http://arcadehacker.blogspot.com/2019...

Credits

RetroRGB
​⁠​⁠​⁠​⁠​⁠   / @retrorgb  
Sony YR-421 analysis
https://www.youtube.com/live/fkHl-nw2...
Interview with ​⁠Phonedork, brief discussion of the BKM 14L probe
   • RetroRGB Weekly Roundup #41 - Feat Ph...  

​⁠​⁠​​⁠​⁠Zez Retro
   / @zezretro  
Sony YR-421 review
   • The one of a kind S-Video to RGB conv...  

​⁠​⁠​⁠​⁠​⁠Wren Tubes
   / @wrentubes1886  
Degaussing using a drill
   • CRT Degaussing With A Drill  

Andrew One Man Band
   / @andrewonemanband  
Bob Ross Joy of painting cover
   • Bob Ross: The Joy of Painting Theme |...  

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