Hantarex MTC-9000 no glow issue

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seteram

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Hello everyone! I am new to this site and new to arcade repair as of 1 day ago lol. Picked up a merit pit boss superstar machine that when plugged in, makes the startup beep and the lights come on for the buttons, but no activity with the crt screen.

Ripped her apart and found a few places that could be causing the issue. The largest glaring issue however, was the big resistor being absolutely torched to high heaven. First thought was the flyback, but it doesn’t seem to have any cracks or damage, and the other spots associated with that issue don’t seem to be bad either.

What do you guys think? I will put photos below. Planning on getting a couple new resistors to replace the destroyed one, but trying to figure out if I’ll need a fly back as well or a cap kit, etc. let me know what you guys think! Thank you! I want to learn as much as I can and fix this thing up!

In the photos:
- large ceramic resistor destroyed
- maybe R1 cooked?
- some slight scorching on R74
- HOT looks normal also
- aside from these I really don’t see anything out of the ordinary I don’t think?
 

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G

gunblade

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you would need to read the regulator and HOT with a meter, flybacks can short internally so you will not see any physical evidence of failure
normally when that resistor is in the state the flyback, HOT and regulator are bad with possible other supply regulation and/or issues in the horizontal stage
 
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seteram

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gunblade said:
you would need to read the regulator and HOT with a meter, flybacks can short internally so you will not see any physical evidence of failure
normally when that resistor is in the state the flyback, HOT and regulator are bad with possible other supply regulation and/or issues in the horizontal stage
Click to expand...
Thanks for the response! Any chance you have a good schematic for an mtc9000? I can’t seem to find a good enough one to make sure I know what the components I’m looking at are
 
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seteram

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Also, does anyone know where to find mtc9000 flybacks? Everywhere I can find they’re sold out… really hoping I didn’t just screw myself by buying this things lol
 
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M K L

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That's the 10" version.
Start by fixing, if necessary, the power circuit so that you have a stable 130V at the middle pin of the yoke connector with yoke unplugged and 60W light bulb connected to it. If the voltage regulator TR20 is bad, replace it with a BU508A (same as the HOT TR15) or even better the fully insulated BU508AF.
 
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tb2000

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If it turns out to be the flyback , the 10" version is HR7185. Unfortunately they seem very difficult to get hold of. The larger 14"-20" version flyback is HR7025, which is much easier to find and are still available, but I'm not sure if there's a way to use them on the 10" version. The pinouts are very similar between the two and no doubt they could be made to match but the HV output is higher on the HR7025 for the larger CRT and also there must be some other important difference as when using the proper HR flyback testers on them, the HR7025 uses the standard STVDST-01 tester whereas the HR7185 uses the SMONDST-32khz tester same as the HR8068 flyback does for the Polostar monitors.
 
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M K L

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That the 7185 is to be tested with the SMONDST-32 is surely a mistake by HR. Both the Eldor 11050808 (stock flyback) and the HR7185 test as they should with the 15KHz tester STVDST-01 using pin 1 as the HOT collector:
DSCN2691.JPG
DSCN2697.JPG
And this is how the 7185 tests following the instructions on the HR page (32KHz tester and pin 4 as the HOT collector). Error LED on and an EHT level so high it doesn't make sense:
https://hrdiemen.com/reparation/flyback/scheme/7185
DSCN2705.JPG
It should be noted that the 7185 is an exact reproduction of the original Eldor transformer and both have the same inductance on the primary side (on the other versions the inductance is lower):
DSCN2685.JPG
DSCN2678.JPG
 
69er

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Georgian2 said:
Where can one buy these flyback testers?
Click to expand...

There’s a place in Bulgaria’ ashop.bg ‘ they are 195bgn which is about £85 uk then shipping fee & import vat duty ….. I looked once before for such an item but already had reduced the repairs I attempted so thought it too much of a luxury ??? 😜
 
Ace`

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It was years ago so I might be remembering wrong but I am sure I replaced a 7185 with a 7025 and it worked just fine. As even back then 7185s were impossible to find.
 
tb2000

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That's good to know about the HR7185 being able to be tested on the standard STVDST-01 tester. If that's the case then maybe a HR7025 can indeed be used on a 10" Hanty, as it appears the HV level is almost identical on both. Pins seem correct if it tests with pin 1 as the HOT collector. I wonder if pins 5 and 6 are the same and not swapped round as shown on the schematic? Makes you wonder why Hanty used a HR7185 and not just carry on with a HR7025! I did find a place saying they have HR7185 for sale in the USA, might be worth asking them if they ship to the UK. I just went by HR's website as far as connections for the flyback tester goes so never tried to test one using a standard tester. I don't have a SMONDST-32 (I do have a STVDST-01) so couldn't go on personal experience, but it does appear they've got it wrong as M K L says, I did find it odd that they had it testing on the SMONDST-32 considering it's just fits a normal 15khz chassis! I'd like to get hold of one though, as i've got a number of HR8068 and other flybacks used on multisync stuff that i'd like to be able to test rather than install in a chassis and have them blow components if they're faulty. Seen some for sale in the USA, but they use a 110v adapter, i'd assume you can use the STVDST-01 adapter with it? Seems that place 69er mentions has got some also. Donberg has some STVDST-01.
 
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seteram

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tb2000 said:
If it turns out to be the flyback , the 10" version is HR7185. Unfortunately they seem very difficult to get hold of. The larger 14"-20" version flyback is HR7025, which is much easier to find and are still available, but I'm not sure if there's a way to use them on the 10" version. The pinouts are very similar between the two and no doubt they could be made to match but the HV output is higher on the HR7025 for the larger CRT and also there must be some other important difference as when using the proper HR flyback testers on them, the HR7025 uses the standard STVDST-01 tester whereas the HR7185 uses the SMONDST-32khz tester same as the HR8068 flyback does for the Polostar monitors.
Click to expand...
Okay this might be a dumb question, but I’m going to have to basically take everything apart to all this testing the correct way right? I have very little experience with any of this stuff so I’m trying to make sure I’m going about it the right way before I just start desoldering parts hahah.
 
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M K L

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Point A is where the 130VDC from the power circuit is ready to go to the deflection circuit. The trace goes from A to B. When the yoke connector is in either of the green headers, B and C are jumpered and all the points ABCDE are the same. Now, with the yoke unplugged, measure the resistance of any of the points CDE and the big aluminium heat sink (removed in my pic) which is grounded. If the resistance is zero or very low ohms, there is a shorted part in the deflection and this is most likely the horizontal output transistor TR15 (HOT). At this point, and only if you have decent desoldering skills, suck solder off the middle pin of the HOT (point F in my pic) so that the leg isn't in contact with the surrounding pad anymore. If after doing this, the resistance across C (or D or E) and the heat sink goes up to several kilo ohms, the HOT is shorted and should be replaced. The flyback would not have a short across the primary and secondary sides so it would probably be OK.
DSCN2724.JPG
 
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