• Enraged
  • Embarrased
  • Drunk
  • Down
  • Depressed
  • Crying
  • Crazy
  • Cool
  • Cocky
  • Bemused
  • Awesome
  • Annoyed
  • Angry
  • Amused
  • Friendly
  • Geeky
  • Godly
  • Happy
  • Hateful
  • Hungry
  • Innocent
  • Meh
  • Piratey
  • Poorly
  • Sad
  • Secret
  • Shy
  • Sneaky
  • Tired
  • Wtf
  • Page 1 of 30 12311 ... LastLast
    Results 1 to 10 of 300

    Thread: CRT TV EEPROM & Micom hacking for RGB (+tube swap for 48cm to 51cm TV)

    1. #1
      buttersoft's Avatar
      buttersoft is offline
      is chasing the beam
       
      Meh
       

      Join Date
      Mar 2015
      State
      Tasmania
      Posts
      1,113
      Mentioned
      52 Post(s)
      Quoted
      372 Post(s)
      Australia

      CRT TV EEPROM & Micom hacking for RGB (+tube swap for 48cm to 51cm TV)

      This thread started out being about swapping a 48cm tube onto a chassis that originally had a 51cm tube, but has turned into a discussion of EEPROM and microcontroller hacking to enable RGB on old Australian (possibly NZ) SD CRT TV's on which it appears to have been disabled by the microcontroller (Micom). Discussion of the latter begins a few pages in, and it's all very much a work in progress.

      Note that not all old sets need the above, in progress hack in order for you to RGB mod them. As a very rough guide, if the neckboard has colour pots for RGB bias/gain, you probably don't need to worry, injecting signals into the jungle IC should just work. For newer sets without neckboard pots, try inserting RGB, and see if it works.

      Remember that the shumps thread is a better place for information on the subject of RGB hacking!

      I've been hunting for more RGB-moddable chassis to drive 20"/48cm TV tubes - the standard 2ohm/14.8ohm ones in old cabs. They're getting harder to find though.

      After @namastepat's just-make-it-fit suggestion I was wondering about swapping out the chassis from a 51cm TV and using it on a standard 48cm tube. Do the 51cm tubes typically have the same yoke resistances and pinout? Is the required HV going to be much different? I know I've seen chassis that will suit multiple tubes.

      At the moment I'm looking at this job here - https://my.mixtape.moe/rnatkf.pdf.

      That service manual says the chassis can handle 14", 20" and 21" tubes. (In this particular case I suspect the 20" and 21" tubes might be the same thing but US vs Aus names? i.e both the same 51cm tube, not a 48cm one?)
      Last edited by buttersoft; 5th October 2017 at 03:09 PM.

    2. #2
      NEO-GEO Man's Avatar
      NEO-GEO Man is offline
      This user has no status.
       
      Happy
       

      Join Date
      Feb 2011
      State
      QLD, Australia
      Posts
      1,620
      Mentioned
      30 Post(s)
      Quoted
      350 Post(s)
      Ukraine
      Need to recalibrate a few things some times, but if the yoke is the same and tube pinout is the same, then it can be made to work.

      48cm and 51cm tubes are both different sizes, if that is what youre asking at that end there? Theyre not just the same tube measured differently.

    3. #3
      buttersoft's Avatar
      buttersoft is offline
      is chasing the beam
       
      Meh
       

      Join Date
      Mar 2015
      State
      Tasmania
      Posts
      1,113
      Mentioned
      52 Post(s)
      Quoted
      372 Post(s)
      Australia

      Quote Originally Posted by NEO-GEO Man View Post
      Need to recalibrate a few things some times, but if the yoke is the same and tube pinout is the same, then it can be made to work.

      48cm and 51cm tubes are both different sizes, if that is what youre asking at that end there? Theyre not just the same tube measured differently.
      Good to hear. Do you know if the yoke and pinout are typically the same though? What are the typical readings and pin no.s for a 51cm TV tube? I'm sure Joey would know... I might grab one and test it. EDIT: I suppose i could try reading tubular, but if there's a shortcut here i'll take it

      It's the chassis swap i want to do, the tubes sizes were more about Aus vs American terminology - we'd call a 48cm a 20" tube, they'd callit 19". We'd call a 51cm tube 21", but i'm not sure what they'd call it. The service manual lists 14", 20" and 21", but i thought the last two might be describing one tube, not two different sizes

    4. #4
      dezbaz's Avatar
      dezbaz is online now Vector Collector
      is doin' fine!
       
      Meh
       

      Join Date
      Jan 2007
      State
      Ballajura Perth WA
      Posts
      8,092
      Mentioned
      69 Post(s)
      Quoted
      467 Post(s)

      Chassis swap between 51cm and 48cm tubes?

      US use the viewable size. So typically they call the exact same tube 1" less than we do.

    5. #5
      NEO-GEO Man's Avatar
      NEO-GEO Man is offline
      This user has no status.
       
      Happy
       

      Join Date
      Feb 2011
      State
      QLD, Australia
      Posts
      1,620
      Mentioned
      30 Post(s)
      Quoted
      350 Post(s)
      Ukraine
      Quote Originally Posted by buttersoft View Post
      Good to hear. Do you know if the yoke and pinout are typically the same though? What are the typical readings and pin no.s for a 51cm TV tube? I'm sure Joey would know... I might grab one and test it. EDIT: I suppose i could try reading tubular, but if there's a shortcut here i'll take it

      It's the chassis swap i want to do, the tubes sizes were more about Aus vs American terminology - we'd call a 48cm a 20" tube, they'd callit 19". We'd call a 51cm tube 21", but i'm not sure what they'd call it. The service manual lists 14", 20" and 21", but i thought the last two might be describing one tube, not two different sizes
      If the tube is from the same series the pinout will be the same. Its in the service manual.

    6. #6
      buttersoft's Avatar
      buttersoft is offline
      is chasing the beam
       
      Meh
       

      Join Date
      Mar 2015
      State
      Tasmania
      Posts
      1,113
      Mentioned
      52 Post(s)
      Quoted
      372 Post(s)
      Australia

      @soyl any chance you'd know the answer to this one? I'm looking to swap a chassis from a 51cm/21" tube to a 48cm (US19"/A20") tube. Assuming both have the same B10-277 socket, and roughly the same yoke resistances, what else should I look out for? Would you happen to know typical yoke measurements on a 51cm TV tube, or are there too many different types? Are they all B10-277 pinout?

    7. #7
      NEO-GEO Man's Avatar
      NEO-GEO Man is offline
      This user has no status.
       
      Happy
       

      Join Date
      Feb 2011
      State
      QLD, Australia
      Posts
      1,620
      Mentioned
      30 Post(s)
      Quoted
      350 Post(s)
      Ukraine
      Quote Originally Posted by buttersoft View Post
      @soyl any chance you'd know the answer to this one? I'm looking to swap a chassis from a 51cm/21" tube to a 48cm (US19"/A20") tube. Assuming both have the same B10-277 socket, and roughly the same yoke resistances, what else should I look out for? Would you happen to know typical yoke measurements on a 51cm TV tube, or are there too many different types? Are they all B10-277 pinout?
      Heater voltage, G2 calibration, drive settings, its all in the service manual

    8. #8
      soyl is offline
      This user has no status.
       
      ----
       

      Join Date
      Mar 2011
      State
      Europe
      Posts
      38
      Mentioned
      5 Post(s)
      Quoted
      22 Post(s)
      Quote Originally Posted by buttersoft View Post
      @soyl any chance you'd know the answer to this one? I'm looking to swap a chassis from a 51cm/21" tube to a 48cm (US19"/A20") tube. Assuming both have the same B10-277 socket, and roughly the same yoke resistances, what else should I look out for? Would you happen to know typical yoke measurements on a 51cm TV tube, or are there too many different types? Are they all B10-277 pinout?
      They're a mix of small/narrow neck 29mm (B10-277) and minineck 22.5mm (B8-294). Thomson, Samsung and Philips only used the former and those cover the vast majority of 21" TV tubes. Mininecks are mostly found on Japanese tubes (like the Toshiba JAR family). The yokes are pretty much in the same range as the typical 20" ones (H inductance: 2.00-2.70mH; V inductance: 24-30mH; H resistance: 2.3-3.5ohm; V resistance: 13-15ohm). And as always with tubes from different manufacturers the filament is rated differently (higher/lower current more than voltage) so the resistor in series with the heater voltage may need to be changed accordingly.

    9. #9
      buttersoft's Avatar
      buttersoft is offline
      is chasing the beam
       
      Meh
       

      Join Date
      Mar 2015
      State
      Tasmania
      Posts
      1,113
      Mentioned
      52 Post(s)
      Quoted
      372 Post(s)
      Australia

      Quote Originally Posted by soyl View Post
      The yokes are pretty much in the same range as the typical 20" ones (H inductance: 2.00-2.70mH; V inductance: 24-30mH; H resistance: 2.3-3.5ohm; V resistance: 13-15ohm).
      Ok, so the 51cm tube that's with the chassis has the right pinout but slightly lower resistances - 2.1ohms & 10ohms @ 20mH. (A51JSY63X, 6.3v heater, 50V G1, CR-23)

      There is a 48cm tube listed in the service manual for this set, though I do not know its yoke resistances or inductance - (A48QAD220X, 6.3v heater, 70V G1, CR-23)

      And i have a few 48cm tubes with the classic 2.3ohms & 14.2ohms. (A48KMX12XX or equivalent, 6.3v heater, 50V G1, CR-23)

      So the pinout is right, and the horizontal coils might be ok, but the vertical coils and G1 seem a bit... interesting. Why is the compatible 48cm tube listed at a higher G1? That's the bias voltage, isn't it? The service manual probably isn't complete, but there's a handwritten note scrawled on the only schematic (last page) saying it's for both the 51 and 48cm tubes. No alternate or swapped parts are indicated, so how would the increased G1 be handled? And I was hoping there'd be a single series resistor to swap out for the vertical deflection, like for the heater even if i don't need to swap it, but no such luck. I'll keep staring at the schematic.

      I guess I'm asking for advice from here. This is more a test case, as there are no pots inside beyond the B+ setting, no real description of the EEPROM table, and I don't have the remote to get into the service menu. But working, suitable 48cm sets are getting harder to find

      EDIT: Service Manual linked in original post.
      Last edited by buttersoft; 27th April 2017 at 10:19 AM.

    10. #10
      soyl is offline
      This user has no status.
       
      ----
       

      Join Date
      Mar 2011
      State
      Europe
      Posts
      38
      Mentioned
      5 Post(s)
      Quoted
      22 Post(s)
      You're using a chassis, not a rejuvenator. The cathode-G1 voltage is handled by the chassis which varies the negative bias of the G1 grid through the brightness control. You shouldn't worry about that.

      As for the lower values of the vertical coil, the chassis will likely handle that with no problem (horizontal yoke, now that would be a totally different matter). There is surely a resistor in parallel with the vertical yoke and one in series with one side of the vertical yoke. It's possible to lower the value of these resistors to accomodate vertical yokes with lower impedances.

    Page 1 of 30 12311 ... LastLast

    Thread Information

    Users Browsing this Thread

    There are currently 1 users browsing this thread. (0 members and 1 guests)

    Tags for this Thread

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •