Hantrex MTC9000 problems

Turlock

Hi folks, my screen in my CAB has packed it in, haven't used it for a while and although about a year ago it intermittently worked its completely stopped now.

When I power on the CAB there's absolutely nothing happening with the screen. With a multimeter I can see there's 220v going to the chassis power connection ok but I'm not sure what happens after that.

I'm in Dundrum in Dublin and just wondering is there anyone someone could recommend to take a look at it for me?

Cheers!

I'd just send it to grand or gunblade in the UK.
Easiest option by far

Turlock

Cheers is there a contact around for him? Signed up to the UK forums but not able to PM him on there yet

Just to confirm the process (read up loads and watched loadsa youtube videos)

Plug everything out
First the dangerous part is the anode connecting to the screen so I've discharged that (I'll do it again when I get back to it just to confirm)
Second are that some capacitors might still have a charge so I'll steer clear of actually touching anything

With the monitor discharged I'll unclip the anode from the top of the monitor
remove the connections on the chassis itself
wiggle the neckboard off the back of the tube
Unscrew the chassis board and remove from the cabinet

I'm going to do all this at the back of the cabinet instead of removing the monitor, I presume that's ok? Like they're designed with that sort of access

Thanks for the reply, much appreciated

Turlock

That worked fine so have the chassis out now and I'm boxing it up, so just need the contact for Grant and I'm sorted

geotrig

http://www.error24.co.uk/

This is grants site

o1s1n

Also fairly active over on Arcade Otaku, I've dealt with him a couple of times via pms over there. Username is grantspain.

Turlock

Cheers sent him off a mail there from the site, if I don't hear back I'll chase him up on Arcade Otaku

Thanks again for the help!

While you have it out you should clean it if its manky,
Just cover it with Mr.Muscle and work it in with a paint brush then hose it down in the bath/outside.
Will be like new.
Then let it drip dry for a while or leave it in the sun.
They come up like new.

Turlock

Ha I was thinking, its absolutely covered in dirt from the beginning of time so I might just do that, are you serious about hosing it down though? Water plus electrical components don't generally mix

Grant got back nice and quick so I have it boxed up ready to stick into Parcel Motel later, hopefully it comes back clean :P

o1s1n

As long as you don't cover them in water while they're on they're grand

Sure one of the best ways of cleaning old arcade PCBs is in the dishwasher. You just want to make sure they're given plenty of time to dry out and there arent any remnants of water left in and around components.

Skerries

BGOllie

I run everything through some washing up liquid with paint brush and the hose or in the sink to clean them up .
Electrical components and water do just fine ... as long as you don't do it when it's plugged in and you let it dry properly

eddhorse

Yep I've scrubbed and hosed my monitors too, minty fresh.
Also put a VIC-20 in the dishwasher.

Grant is a legend.

80s Synth Pop

Where is he getting the parts from to do the repairs? I've been looking for a new flyback for a MTC9110 for years.

80s Synth Pop

80s Synth Pop wrote: »

Where is he getting the parts from to do the repairs? I've been looking for a new flyback for a MTC9110 for years.

Donburg in Donegal is usually good,
Swallow amusements either

eddhorse

Was on that Donberg website before, has a lot of stuff.
https://www.donberg.ie/

80s Synth Pop

cheers for the donberg link eddhorse & brownfinger. I ordered one of these:
https://www.donberg.ie/descript/h/hr_7185.htm

80s Synth Pop

80s Synth Pop wrote: »

cheers for the donberg link eddhorse & brownfinger. I ordered one of these:
https://www.donberg.ie/descript/h/hr_7185.htm

20 quid!
Thats for nothing.
If you get it going order a spare.

80s Synth Pop

I think it's for a 10" screen though and mines a 25"....

eddhorse

The MTC9110 is used for the 25" tubes I believe.

http://www.swallowam.co.uk/monitor.php

MTC9000. This is the chassis covered by repair guide article. It will run 14", 16" and 20" tubes. Looking from the back, to the left just behind the video input is a slide switch. There is the small removable control PCB in the centre containing 6 controls. The large heat sink round the LOPT has TR15 (BU508A), IC1 (TDA1670A), TR17 (BDX53A) mounted on the left and the large power resistor on the right.

MTC9110. This is the same as the MTC9000 chassis (above) with one major addition. A large fan mounted over the LOPT. Because of the additional power that is required to drive the 25" CRT, a fan has been mounted on the heat sink that supports the voltage regulator and the horizontal output transistor. A temperature sensor has also been mounted on the heat sink. Should the fan fail, the sensor will detect the rise in temperature and shut down the monitor.

Polo. This is a "Free Voltage" chassis which can use a supply from 180V to 264V 50Hz. Europe or 80V to 130V 60Hz. USA. It will run any tube from 10" to 33". Looking from the back, it is easily identified by the large power supply cage on the left hand side.
Repairing the MTC9000 Chassis. Don't overlook the obvious. You could spend hours trying to find some curious fault when the obvious is staring straight at you. You don't need lots of expensive test equipment, just common sense and observation. Make sure all plugs are firmly seated and that the black earth wire to the neck board from the tube braid is always connected to the monitor.

1. Dry joints. Check the entire chassis for dry joints and cracked or burnt tracks on the PCB especially around the LOPT, power plugs and large components.

2. LOPT. After you have checked all the fuses, listen for the static build up when you switch on. If you don't hear this, is the large power resistor mounted to the side getting very hot? The high-wattage resistor (R105 330 ohms, 30 watts) that is connected in parallel with the power regulator transistor suffers when the Over Current Protection circuit (OCP) shuts down the regulator circuit due to a short. Current from the unregulated power supply passes through R105 to ground. This 30 watt resistor is now dissipates over 60 watts of power. That is why it burns and gets very hot. It should only get warm. If there is no static and the 330 ohm resistor gets extremely hot then there is a good chance the LOPT or the horizontal output transistor [section 5] has shorted out. Check for leakage between pins 1, 3, 9 of the LOPT and pin 5. Swelling or cracks on the side of the LOPT will confirm this. Hantarex does not manufacture their own high-voltage units and, unfortunately, they got a bad batch of units from the manufacturer. If replacing the LOPT, check R81 (4.7 ohm 9W) as this could also fail. There is a side-effect to the operation of the OCP circuit that can be somewhat confusing if you don't know what to look for. In just about every other type of monitor, this failure will blow the fuse but in the Hantarex MTC 9000, it activates the OCP. The fuse will not blow.

3. Check the 130V. The B+ voltage is best measured from black wire link in the scan coil plug. The scan coils are the ones round the neck of the tube. Place the red meter probe on the black link and the black probe to metal chassis. Alternatively use test point 10 (TP10). This should read 130V DC and should not vary by more than a few volts. If this is well below the 130V, three things could be at fault.
A. C34, a 22MFD 160V capacitor. 2. C53, a 470MFD capacitor. You will have B+ at 60-70Volts.
B. TR20, the TIPL762 (BU508) power transistor mounted on the chassis by the 330 ohm resistor is open circuit. If you want to check it with a meter, remove it first.
C. Check R110, a 33K ohm resistor at the top right corner. Lift one end and measure it. If it needs replacing, use a 1/2 watt or higher resistor in place of the 1/4 watt one fitted.
D. If the B+ voltage is to high and you have a wavy picture, TR20 may be short circuit. Another cause of wavy screens is C53.
E. Another reason for a missing B+ 130V is the activation of the X-Ray protection circuit. A reference voltage is produced from the LOPT and is fed via a resistive divider to pin 8 of IC2 (TDA 2595). The voltage here is compared with an accurate reference voltage and if the EHT exceeds 28KV, the voltage at pin 8 operates a trigger circuit which inhibits the oscillator and shuts the monitor down. This can be noticeable when the monitor comes on briefly then shuts down. Temporally disable this circuit by lifting one end of D10. Now apply power to the monitor. If the monitor now gives you a picture, the X-ray circuit is activating. The problem could be in the voltage regulator circuit. Never leave a monitor running with the X-ray circuit disabled. Check C36, C37, C40 and C41.

4. Vertical Output. Check that TR15 (BU508A) has not gone open or short circuit by measuring it out of circuit. If you have no vertical sync. Check the value try replacing C18 (10MFD 25V).

5. Horizontal output. The horizontal output transistor TR15 (BU508A) is the hardest working transistor in the monitor. All the current for the horizontal deflection coil in the yoke and the flyback transformer passes through the this transistor. If this has shorted you will have a dead monitor.

If you have a horizontal white line across the centre of the screen, then IC1 (TDA 1670A) could be at fault. Equivalents for IC1 are TDA 1670 and TDA 1675. If it blows R94 (3.9 ohms) will burn out as well. If this resistor is replaced, mount it away from the PCB as it can burn the board. The supply for IC1 is 26V DC and appears on pin 2 via D5 (IN4004). (TP13). Is the adjustment board at the back fitted correctly?

If you have limited control of the horizontal hold after 5-10 minutes, check C38 (1MFD 63V), D5 (IN4004) and D4 (IN4148). If the problem is intermittent, check C9 (100MFD 35V).

6. Other things to check. ZD1, a 12 Zenner diode if short circuit, will stop the 12V the supply for the TDA 2595 oscillator.
If the supply fuse blows when you switch on, one or more of the rectifier diodes could be short circuit. D19-D22. Any 400V 1.5A diode will do, (BYV96C or IN4007).
If the brightness varies with the image and the 130V B+ is correct, check that R90 (270K) is not open circuit.
Again if the 130V B+ is correct and you have white fly back lines across the picture, check components associated with TR18 (BC639).
If you have a plain white screen, check the voltage across C205 on the neck board. This should read around 190V DC. If not check R126 (47 ohm) and D15 (BYD 33G).
Insufficient width problems and picture varying in size can be caused by C42.
Shimmering at the edges of the picture can be caused by C57 (1000MFD 35V). If there is whistling as well check C34 (22MFD 160V).
R122 glows red hot. Lin coil open circuit.
Ticking noise with any supply voltage up to 128V. LOPT.
Exceptional width when all else fails. LOPT.

eddhorse

Search for Hantarex:
https://www.donberg.ie/search?query=Hantarex&wordflag=and&maxlines=100&group=00

I think it's this one.

https://www.donberg.ie/descript/h/hr_7191.htm

MontgomeryClift

There should be a long part number down the side of the old LOPT to help identify it.

Turlock

Hi Folks, So whipped out my chassis and fired it across to Grant who gave it the once over. Great recommendation as the chap is just excellent. He found a few dodgy caps and replaced them but they would address picture quality as opposed to it not powering up.

I'd checked the power supply (which is a Hantarex 250 US) and the plug had 220v AC and 135DC coming into the chassis. Grant let me know that a sign of the chassis working ok was if the fan came on. Got the board back plugged it all back together and low and behold it powered up. Picture is amazing, there was some blotches so they've been completely sorted.

About 30 mins later then "click" off went the monitor and chassis. Checking the power into the board again the 220v is there but the 135v has disappeared which makes me think there's something up with the PSU.
What's my best bet to get it sorted? Post it to Grant or is there someone in Dublin that could take a look, alot more straightforward to work on compared to the chassis so happy enough to give someone a go on it here if they were generally electronic savey

Thanks for the help so far, really really appreciated and great to at least see the cab powered up for a short while again

If it's an intermittent issue with the DC line what do you think I'm looking at, dry solder joints or blown caps?

o1s1n

Is it a regular jamma cab? Should be able to just drop in a new psu.

Turlock

No it's mame now, so all the 5v/12v feeds aren't used I'm only using the 220v AC and 135v DC going to the monitor chassis

Doesn't look to be alot of options for monitor only power supplies so reckon I just need to get my one sorted

Have you tried another isolation transformer on the monitor? That should be your next port of call if you suspect power issues.

geotrig

It sounds like those hanterax us250 power isolution transformers ?, its a long time since i had one but check that the fuse is ok (on powersupply) they have a habit of blowing and being flakey in general.

Turlock

geotrig wrote: »

It sounds like those hanterax us250 power isolution transformers ?, its a long time since i had one but check that the fuse is ok (on powersupply) they have a habit of blowing and being flakey in general.

haha yeah its a us250 and that's what I'm reading on the internet alright, not the best made psu ever checked the fuses with a multimeter and they're fine so looks like it needs a cap kit and solder redone

I've found a power supply place down in Rathnew so he's said he'll take a look for me. I'll let ye's know how it goes

eddhorse

Hopefully that didn't affect the monitor chassis after it was fixed.

Any pics of the power supply and isolation transformer?

Surprised it's 135V , seems a strange number.

Edit: Read through this
https://touch.boards.ie/thread/2056155861

Also one here for €59
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.es%2Fulk%2Fitm%2F142782864527

If you do have a guy working on it then get the schematic for them, might help.

I'd bet a 110v transformer would work

BrownFinger

BrownFinger wrote: »

I'd bet a 110v transformer would work

Just about to post the post the same, any 110v will be enough

eddhorse

Did read elsewhere it was 135v , very strange.

eddhorse

eddhorse wrote: »

Did read elsewhere it was 135v , very strange.

Most stuff will work with +\- 10/15% on the incoming voltage

o1s1n

BrownFinger wrote: »

Most stuff will work with +\- 10/15% on the incoming voltage

Yeah sure I'd say the majority of people use a 110v Stepdown for Japanese consoles when in fact it 'should' be a 100v one.

Turlock

eddhorse wrote: »

Hopefully that didn't affect the monitor chassis after it was fixed.

Any pics of the power supply and isolation transformer?

Surprised it's 135V , seems a strange number.

Edit: Read through this
https://touch.boards.ie/thread/2056155861

Also one here for €59
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.es%2Fulk%2Fitm%2F142782864527

If you do have a guy working on it then get the schematic for them, might help.

Thanks for that, great link to a replacement unit and off your advice I included the schematic which made life much easier for the PSU repair guy.

So to recap here's what's happened to date, I'd previously built a mame machine from a second hand cabinet I got on here that came with a screen. Alot of fiddling to get it all set up and working but got there after 3 solid days and all was working fine.
Left it for a while tucked away in the corner of one of the back room and on going to it now and again most of the time it wouldn't power on. Thought it was the rear door switch but when I found out it wasn't I was a bit lost.

Eventually bit the bullet and came on here to see where to go with it and got recommended Grant in the UK. After decharging my monitor using a screwdriver on the end of a wooden sweeping brush for maximum clearance I sent it across but once with him he found no major issues bar a few caps that would affect the image quality (worth noting that the screen did have a discoloured blotch down the left corner, thought it was someone playing with a magnet on the front of the screen at some point) he replaced and sent the chassis back to me.
He'd advised that I may have a power problem feeding the screen so I did a full check on the power going into the chassis, both 220VAC and 135VDC worked fine. In saying that there was alot of dodgy wiring in the cabinet so while waiting for my chassis to get back I tidied it all up and soldered all the wires that'd been twisted together.

With that done I decided to boot my XP mame machine with an external monitor to makes sure that was ok. It wasn't and I mean really wasn't, couldn't boot but then after a repair of the disk it threw other errors so had to reinstall windows on top of it to get it to work and even at that I wasn't confident so spent another full day rebuilding it all from scratch, to make it worth my while I added NES, SNES and Mega Drive games alongside Mame in HyperSpin. Turns out that hardest part was activating windows XP again as the online service seems to have gone off the air

With that rebuilt the chassis turned up, I stuck it in and hey presto all was good with the world again. I still had config to do on the freshly built XP install and half an hour into that the monitor went off and wouldn't restart, using a multimeter I confirmed the 135V rail was dead.

I found PSRA.ie in rathnew, dropped my power supply down and picked it up again two days later with a capacitor replaced. Price was similar to what chassis work costs from Grant.

While waiting for my PSU, I finished the config of the XP build and then backed up the disk in case it goes again.
When I got the PSU back in it went, the cab was rebuilt and tested and finally I'm back in action

Thanks a mill for all the help on here, great to get all the info and funny to think back to the start of this I hadn't a breeze what was going on and now I know the internals of my cab and CRT inside out!

Proof of my working, perfect screened arcade machine:

eddhorse

Great work and thanks for the full explanation. It will help someone else down the line.
Nobody knows anything with these cabs until you start digging in there and researching.
Well done.

remoteboy

Picture looks amazing. Nice job. I need to give grant a shout and get mine looked at.