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Hantarex MTC900/E

Printed From: ukVac.com
Category: Technical
Forum Name: Tech, Maintenance & Repairs
Forum Description: Need Help? Ask Here
URL: http://www.ukvac.com/forum/forum_posts.asp?TID=355017
Printed Date: 22 Jul 2017 at 1:45am


Topic: Hantarex MTC900/E
Posted By: BaldiGit
Subject: Hantarex MTC900/E
Date Posted: 20 Nov 2016 at 1:39pm
Does anybody know where I can get a horizontal drive transformer (TH2) for a Hantarex MTC 900/E
Monitor (Part Number 28010080). New or 2nd hand...??? Confused



Replies:
Posted By: tb2000
Date Posted: 20 Nov 2016 at 1:58pm
No not available from what I've found, only second hand if you can find one! I'm looking at getting it reproduced by one of those custom transformer companies but I never seem to get around to it!


Posted By: big10p
Date Posted: 20 Nov 2016 at 1:59pm
I have an old 900/e chassis I've started breaking for parts. You're welcome the the TH2 if you want it, but I have no idea if it's a worker, or not.

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Posted By: BaldiGit
Date Posted: 20 Nov 2016 at 2:21pm
Thanks big10p, I'll take you up on that. Thumbs Up

tb2000 I have made enquiries at Majestic transformers. I'll let you know what they say.


Posted By: big10p
Date Posted: 20 Nov 2016 at 2:28pm
Originally posted by BaldiGit BaldiGit wrote:

Thanks big10p, I'll take you up on that. Thumbs Up
No probs, mate. Wink PM reply sent.


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Posted By: RGP
Date Posted: 20 Nov 2016 at 6:33pm
I may have a couple of these i've pulled out of cracked, not-worth-repairing chassis.  

I know Gunblade has had the unfortunate task of rewinding a couple by hand in the past.

If you get a magnifier out you will find the hair-width wire from the coil has broken probably near the coil itself, it is just about ok to unwind 1/4 or 1/2 of one turn to reconnect it but its micro surgery level.

Getting them reproduced shouldn't be that hard and the ratio should be derivable via maths based on the resistance of each coil.



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Parts for fixin' and stuff for sale in our webstore https://shop.retrogamesparty.co.uk" rel="nofollow - here


Posted By: BaldiGit
Date Posted: 20 Nov 2016 at 6:53pm
Thanks for the offer. I might take you up on that if 'big10p's doesn't work out.Thumbs Up

If I can't get one, I am considering a rewind it by hand (plus cordless drill if I can count that fast). In my youth I did some part time work at a transformer factory and this, (appart from the fine wire) looks like one of the easier ones. No laminations, one primary and secondary with no centre tap, plus round one bobbin.

Unfortunately the wire has dissapeared into the insulation on mine. But if I unwind the outer winding and remove the insulation I might be able to find it I suppose. Smile


Posted By: david_orton_2000
Date Posted: 21 Nov 2016 at 5:14pm
Hey there,

If this is the same as the one on the 900, i have some pcbs I could sell you...
i.e. ones often found in Tron.
If you have the resistance measurements for me to test in advance, please supply them. :-)

Cheers,
DaveO.



Posted By: BaldiGit
Date Posted: 30 Nov 2016 at 1:33pm
Well I've managed to procure a 2nd hand TH2 transformer (thanks again big10p) that had met the same fate. But the wires where still evident and I managed to re solder them back. That gave me a primary resistance of around 2M ohm (not sure if that's right.... but it was open circuit before). And a secondary of about 0.4 ohms. I have carefully changed all the capacitors, checked and double checked values and orientation. And was expecting good things to happen when plugged back in....... ?? But it was just the same ??.
Does anyone have a FAQ or flow chart of a repair sequence? There are plenty of test points on the board. But without knowing what to expect, they're useless.

Also.... I'm initially testing it without a video signal. Looking for neck glow and static on the screen. This isn't one of those monitors with a spot killer/stand by function is it...???


Posted By: gunblade
Date Posted: 30 Nov 2016 at 2:00pm
70 ohms one side and about 1 ohm the other


Posted By: PaulSwan
Date Posted: 30 Nov 2016 at 4:48pm
This transformer is also used on the MTC-90 "MT" daughter board as an alternative source.
Paul.


Posted By: BaldiGit
Date Posted: 30 Nov 2016 at 7:19pm
Hmm.... If that's is correct. I still havent repaired TH2 Ermm.....!!!


Posted By: gunblade
Date Posted: 30 Nov 2016 at 11:02pm
it is correct,i have repaired hundreds of them


Posted By: big10p
Date Posted: 01 Dec 2016 at 2:19pm
Sorry to hear you didn't have any luck with the transformer, Gary. Was the neck board any use? If you can find a manual online, I think they should tell you what the test points are for.

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Posted By: BaldiGit
Date Posted: 01 Dec 2016 at 6:14pm
The neck board looks great, but I was going to get the monitor working first then swap it. Just incase I added to my problems.... I have a manual that gives me a circuit and a brief description. But no FAQ or fault finding flow chart Cry.

But now at least I have 2 TH2's. So I should be able to count the windings off and rewind with new wire. Thumbs Up


Posted By: BaldiGit
Date Posted: 01 Dec 2016 at 7:40pm
gunblade.. You don't know how many turns the fine wire is? I'm just disecting my old one and the outer winding is 21 3/4 turns. But that's the easy one....... Confused


Posted By: BaldiGit
Date Posted: 02 Dec 2016 at 1:45pm
Well I've removed the outer winding and soaked the coil in thinners. Which has loosend the shellac varnish and allowed me to unwind the insulation tape.
I have found the 2 ends of the coil and got a resistance of 74.5? which is in the ball park. I'll extend these ends with something a bit chunkier and I've ordered some HT winding insulation tape. Plus I have some insulating varnish in stock.

So hopefully that'll do it. Thumbs Up


Posted By: gunblade
Date Posted: 02 Dec 2016 at 3:01pm
yep 75 ohms is correct


Posted By: BaldiGit
Date Posted: 02 Dec 2016 at 4:32pm
Thanks Gunblade. Thumbs Up


Posted By: BaldiGit
Date Posted: 08 Dec 2016 at 7:36pm
Transformer all repaired, insulated and re-wound. I have 75 ohms one side and 0.7 ohms the other. Between the windings and to the frame is open circuit as would be expected unless I had a short.

But still the monitor is dead Ouch.......

Any ideas chaps????


Posted By: gunblade
Date Posted: 08 Dec 2016 at 10:23pm
my advice is to either send it for repair or replace the chassis


Posted By: BaldiGit
Date Posted: 09 Dec 2016 at 5:03pm
Hmm.... I hate to give up. But there's an old 19" LCD looking like a promising replacement at the moment. Unhappy


Posted By: gunblade
Date Posted: 09 Dec 2016 at 5:36pm
trouble with chassis this age is the amount of issues,you fix one thing and another appears
not a nice chassis to start with tbh


Posted By: gunblade
Date Posted: 09 Dec 2016 at 5:52pm
i would suggest getting a hanty mtc9000 to replace this 900e-tb2000 normally has a few for sale
its an exact match chassis-just need to know what crt socket is used 


Posted By: limpy
Date Posted: 09 Dec 2016 at 5:56pm
Originally posted by BaldiGit BaldiGit wrote:

Hmm.... I hate to give up. But there's an old 19" LCD looking like a promising replacement at the moment. Unhappy

lcd will look sh*te.
gunblade is the "challenge anneka" of the arcade monitor world. he makes stuff work so its up to you!
fantastic crt or vomit lcd....
give him a pm mate.
your not giving up. you have selected to put it in better and quicker working hands than yours ;)
knowledge is power etc etc


Posted By: gunblade
Date Posted: 09 Dec 2016 at 6:12pm
i don't have a big fat arse


Posted By: PaulSwan
Date Posted: 09 Dec 2016 at 8:57pm
I'm finding 900E somewhat more annoying than 900 because of repeated small transistor failures and the 900E has a silly amount of those in the RGB pre-amp. God knows why they dropped the integrated pre-amp in favour of a transistor fest.

I'd try a new TDA2593 since it's socketed and easy to swap out to try. It'll be dead if that is toast. If you have access to a scope, the 900E USA manual has some nice waveforms to compare against but you'd be getting into the deeper technical knowledge realm...
Paul.




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ZZZ


Posted By: limpy
Date Posted: 09 Dec 2016 at 9:47pm
Originally posted by gunblade gunblade wrote:

i don't have a big fat arse

no but you would look good in a yellow jump suit :)


Posted By: BaldiGit
Date Posted: 10 Dec 2016 at 9:28am
Wow.... Touched a nerve there Embarrassed.

Thanks for the ideas Paul. I was looking at the TDA 2593 as they are cheap and also at the TDA 2653A. I have voltage from the B+, although a bit high, but no HV at all. So it must be on the right hand board somewhere.


Posted By: karlcdoe
Date Posted: 20 Mar 2017 at 3:36pm
Thread resurrection....

Did anyone ever locate a readily available alternate to TH2? I am just working through a few old 900e chasis with no HV and the first two I have looked at appear to have dead TH2s.

So before I ruin my eyesight on transofmer micro surgery seems wise to ask the question.

Cheers

Karl.


Posted By: BaldiGit
Date Posted: 20 Mar 2017 at 7:49pm
Sorry to say no....Cry I was forced to give up on the Hantarex in the end. I was doing up an arcade machine for a friend and i the end he was quite happy with an LCD. 
I did however manage to repair the TH2. I soaked it in paint thinners to soften the varnish and managed to unwind the primary which was only 20 ish turns. I could then see where the wire had come adrift and make a repair. A bit of transformer tape and some varnish and it was all giving the correct resistances. But something else was wrong with it.

I would have liked to have got it going. By a war of attrition there wasn't many components left to check Ouch.


Posted By: Belike
Date Posted: 20 Mar 2017 at 8:06pm
I also have a non-working 900e chassis (used to work 6 months ago), if you send me a pic from the actual part, I can check.


Posted By: karlcdoe
Date Posted: 21 Mar 2017 at 10:28am
Thanks for the comments. I managed to repair 2 of 3 TH2s from the chasis I have (might resort to thinners for no3). However my thinking is something a little more permanent would be nice as the resoldered wire will probably rot off again at some point and unlike the mtc9000 the LOPTs are all still working on the chassis I have.

Belike, the transformers should be about 1 ohm on one side and 70 on the other, I swiped a pic from an old forum post a while back, here it is

http://s1294.photobucket.com/user/ksarcade/media/MTC900_TH2_035_zpsjqlsplvv.jpg.html" rel="nofollow">

cheers

Karl.



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