Main Restorations Software Audio/Jukebox/MP3 Everything Else Buy/Sell/Trade
Project Announcements Monitor/Video GroovyMAME Merit/JVL Touchscreen Meet Up Retail Vendors
Driving & Racing Woodworking Software Support Forums Consoles Project Arcade Reviews
Automated Projects Artwork Frontend Support Forums Pinball Forum Discussion Old Boards
Raspberry Pi & Dev Board controls.dat Linux Miscellaneous Arcade Wiki Discussion Old Archives
Lightguns Arcade1Up --- Bug Reports --- Site News

Unread posts | New Replies | Recent posts | Rules | Chatroom | Wiki | File Repository | RSS | Submit news

  

Author Topic: Hantarex MTC 9000 small points maybe missing ground - Solved  (Read 2363 times)

0 Members and 1 Guest are viewing this topic.

mjnman

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 24
  • Last login:December 27, 2021, 03:45:05 am
  • I want to build my own arcade controls!
Hantarex MTC 9000 small points maybe missing ground - Solved
« on: November 15, 2021, 05:20:09 am »
I have a chassis with a first version of MTC 9000 with small white points in the screen, brilliant effect. (below a youtube video)

I tried to:
- replaced all electrolytic capacitors, total recap;
- replaced ceramic capacitor in the neck board C206;
- replaced flyback;
- tested with another tube;
- replaced transistor on the neckboard, TR201-202-203;
- checked all variable resistors on the neckboard;
- replaced RV7 on main board, brightness preset;
- removed fuse 2 then disabled degauss circuit and removed degauss cable;

I checked the main points and seems to be ok:
TP10 - 133.4
TP12 - 11.9
TP13 - 26.9
TP 1 - 24.8
SP11 - 202.9
G2   - 352.2 (ground on the NECK)

I tried to connect a direct ground cable between big heatsink and power socket and there is a little decreases of defect.
Maybe a bad component connected with ground side?
Please, what i can check? i don't know i can do.
In attachment the scheme of chassis and the video issue.

« Last Edit: December 27, 2021, 03:45:46 am by mjnman »

grantspain

  • I personally prefer "bog trotter"
  • Trade Count: (+1)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6090
  • Last login:Today at 04:37:49 pm
Re: Hantarex MTC 9000 small points maybe missing ground
« Reply #1 on: November 15, 2021, 06:05:03 am »
if you disconnect video cable and obtain a raster by turning up screen volts a little do you still see this issus?

mjnman

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 24
  • Last login:December 27, 2021, 03:45:05 am
  • I want to build my own arcade controls!
Re: Hantarex MTC 9000 small points maybe missing ground
« Reply #2 on: November 15, 2021, 11:58:14 am »
I disconnected the video cable and turn up the brightness and the image seems to be ok (white) but it's same thing with a single color, es. blue or red and connected cable.
Yes. The brightness on flyback work and the contrast switch work.

mjnman

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 24
  • Last login:December 27, 2021, 03:45:05 am
  • I want to build my own arcade controls!
Re: Hantarex MTC 9000 small points maybe missing ground
« Reply #3 on: November 15, 2021, 12:24:47 pm »
I rechecked and the issue is present without video cable...it's very very difficult to see but there is a tiny disturb.

mjnman

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 24
  • Last login:December 27, 2021, 03:45:05 am
  • I want to build my own arcade controls!
Re: Hantarex MTC 9000 small points maybe missing ground - Solved
« Reply #4 on: December 27, 2021, 03:45:55 am »
These are Jesus days...I found the problem.
From beginning I replaced:

- entire recap (solve flickering);
- replaced flyback (nothing);
- replaced ceramic capacitor in the neck board C206 (nothing);
- replaced transistor on the neckboard, TR201-202-203 (nothing);
- replaced ALL variable resistors (nothing);
- removed fuse 2 then disabled degauss circuit and removed degauss cable (nothing);
- replaced TDA1670A (nothing);
- replaced TDA2595 (nothing);
- replaced all transistors BC558B and BC548B (nothing);
- replaced transisitor BDX53A (TR17) (nothing);
- Checked all ground points (nothing);
- Checked all components near ground (nothing);

....at the end the problem was in the PSU!!!!...absurd.
---fudgesicle--- ---fudgesicle--- ---fudgesicle---.