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Toei TC-HV25LMK

RandomRetro

RandomRetro

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Recently picked up a MVS U4 which has a Toei TC-HV25LMK chassis. I haven't worked on one of these chassis before, and frankly can hardly find anything online about it so wanted to start a thread to post what I see and find.

Initial Findings:
  • Lots of adjustment pots, but in hard spot to reach.
  • PCC.Adj (A) and PCC.Adj (B) are on a daughter board; currently not effecting anything though for me.
  • Tons of jumper wires on this thing.
  • Flyback is a pain to adjust when monitor is mounted in the cab.
  • Flyback, top pot is focus, and bottom pot is screen/brightness.
  • CN401/CN402 = Low 15khz / Med 24khz Resolution.
  • Recap kit available from Arcade Parts & Repairs.
Questions:
  • H.Coil and PCC adjustments aren't doing anything; wondering if something is needing a swap in the Horizontal circuit?
  • There is no degauss button connection. I think the degauss for other Toei chassis is J1, but on this chassis it is shorted. Is this chassis auto-degauss?
  • There is a loose ground jumper off the main board, is that supposed to go somewhere or just a spare?
Chassis Pic (Online pic which shows J1 wired in - white wires on left running off the board):
E63E6E5E-7C46-40DC-8039-112EA182E15C.jpeg

Resolution Jumper Pic:
2C30DA04-5923-4E09-A41A-4A9C9E992089.jpeg

PCC Adj pots Pic:
6E059E0A-1BA3-4744-8C9F-7F1B7BD07413.jpeg

Degaussing Jumper (J1) Pic:
087066EA-8703-4B94-808E-97EDBC85CBE8.jpeg

Flyback Pics (top focus, bottom screen):
7EAD93A6-F0A5-4C8D-96A7-61E90777B29E.jpeg
 
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Honestly I am going to use this thing until it dies and then replace the chassis with a MS8 or MS9, which is apparently easily done. For now it works, just sometimes flickers/temporary vertical collapse on a cold start, and it buzzes constantly. The picture is amazing other than a faint blue glow on the left during bright white screens, not sure what that's about.
 
Yeah it is really excellent, it's just a shame they're fragile and replacement flybacks are impossible to find.
 
Nice theard ! From all U4 25" , that goes out to new owners with Toei chassis + toshiba tube and 1 x U4 equiped with toei + hitachi tube !
All i know is Toei comes from factory in majority of U4 25" cabinets
RandomRetro said:
Looks like my flyback may be toast as well. And nope not sure there are good flyback options online. Likely need to find one off a donor chassis.
Click to expand...
I will try to help with an working Toei chassis . Let me know if you still need it :happy:

J1 is 110 , it doest to be shorted
 
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dos said:
Honestly I am going to use this thing until it dies and then replace the chassis with a MS8 or MS9, which is apparently easily done. For now it works, just sometimes flickers/temporary vertical collapse on a cold start, and it buzzes constantly. The picture is amazing other than a faint blue glow on the left during bright white screens, not sure what that's about.
Click to expand...
Haven’t looked into a chassis swap yet, but if the Toshiba tube can handle a MS8 or MS9 chassis that would be an interesting option. Is there any thread discussing this?
 
So I was told a Toei TC-A252S should be swappable on my tube. But trying to find someone that can confirm this is a compatible swap with the Toei TC-HV25LMK. Anyone know?
 
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