What component failure would cause sync issues?

[Nipedley]

Yes I'm back again! I finally got my machine up and running today, after all the work I've put into the chassis, I plug it in only to find it has exactly the same problem as when I first started troubleshooting it 2 years ago xD.

It's had a new cap kit, I've tried all different kinds of wiring, gameboards, power supplies. This has to be a chassis component that's causing it, right? For those of you unfamiliar with my problem, it's vertical scroll on a hantarex mtc-9000. It just REFUSES to lock. I've tried 6 different remote boards!

What component has been causing me 2 years of trouble?! Please help!

[grantspain]

i think you have already tried the sync switch and joining sync wires/trying different input combinations
ic2 tda2595 is common to the sync

[Nipedley]

Thanks! I think you might be right there. Just to cover my bases, is there any other components I should try? Might as well order them all together and try them all in one go =)

[grantspain]

there so many common components its too long to list but ic1 tda1670a is another and check resistor r35(10k)

[Nipedley]

Thanks just ordered those 2 replacement ic's. Will let you know how it goes in a couple weeks (I'm too scared to discharge a monitor until at least 2 weeks has passed ^^)

[Nipedley]

Right I've replaced TDA2595 which is no problem, but after I went to put in TDA1670A I realise that it's not a TDA1670A in its place, its a TDA1675.

Is this a part another engineer has replaced with which is compatible, or perhaps a different revision of board?

Don't want to put the replacement chip in unless I know it belongs there..

[grantspain]

tda1670a is the original mtc9000 vertical deflection i/c
tda1675 is used on later chassis and polo range
if you check the datasheets you will find these two i/cs are virtually identical

[Nipedley]

Is it alright to use the 1670A on this chassis then or shall I have to order a 1675? Damn postal strikes now as well, fantastic!

[grantspain]

well if it were me doing this then yes i would use the tda1670 but you must do what you feel confidant with,its possible someone put the wrong tda in there which is causing the problem with the sync

[Nipedley]

I checked out the datasheets and can't actually find ANY differences only the tda1675 datasheet was printed better =D. I'll go with it, all the pins the same and so are the thresholds so should be no problems (fingers crossed!). I'll let you know how it goes in a couple days.

Thanks for all the help grant! You've been absolutely invaluable with your vault of hantarex knoweldge

[Nipedley]

Oh gawd it's still there!

I'm going to try to describe it best I can, and theres 2 new screenshots (ignore quality, had to downsize with ms paint >.>) and a new video to try and help solve this once and for all..

The picture rolls, it will lock at most for 5 seconds. During this period it still jumps up and down a few pixels. Occasionally there are retrace lines visible on screen (evident in second picture).

I have tried every wiring combination, every type of sync, many many different boards, I have replaced isolation transformers and replaced power supplies, replaced TDA2595 and TDA1670A, done the standard cap kit... probably more I'm forgetting.. Help!

Video link (6mb);

[grantspain]

show me  a pic of your signal wiring,both monitor end and game board end

[Nipedley]

Here you go, colours are different because they meet in the middle with molex connectors (I've also tried about 3x of these over the year(s))

[grantspain]

sega megatech yeah?
ok blue to blue
red to red
green to green
blue/white to black
white to pin5 or 6 on the monitor
all this correct and you have tried the white(sync)in both pin 5 and 6 and adjusted the sync switch?

[Nipedley]

That's right, believe me I've been through every wiring permutation you can think of. I've tried sync in both pins seperately and together, sync switch as well. When I first got the cab it was wired Jamma with seperate horiz/vert sync with its own plug to the monitor and it rolled then as well!

This really has me stumped!

[grantspain]

this could be a game board fault,is there any way you can hook up a different game board or make a scart lead to try on you tv

[Nipedley]

  Done both mate. I've tried; An SNK Prisoner Of War Jamma board, 3 Mega-Tech boards, a Sega Naomi board. Also made an rgb scart cable for an old Sanyo tv I had lying around (which worked).

Tough problem huh? 

[grantspain]

well its proved to be monitor,this is a strange problem to say the least
you could check the 3 transistors tr10,11 and 12 and also check for broken track

[Nipedley]

How do I check a transistor? I'm a newbie to anything I havent done before.. and I've never done that =)

The only broken track on the board is where a previous guy decided to replace the LOPT and lifted a bit, but he fixed it by exposing the copper and soldering onto it. That's what I make of it, anyhow

[grantspain]

you need to set your multimeter to ohms and check across the legs in all combinations and compare readings of all three,if one is faulty then it will read different to the other two
btw is this the top monitor or bottom doing this?

[Nipedley]

Great thanks for the info, I'll check those out soon.

It's the bottom monitor, 20" MTC9000. I also tried swapping the vid. signal for the bottom one to the top and it works fine, just to make sure the video signal was good.

I bought a replacement MTC9000 board from Swallow Amusements but that full-on died on me a little while ago so I thought I'd have another go with this board instead..

[grantspain]

whats worrying me is something that happened a lot with megatechs and playchoice10,there were many instances where techs put the wrong flyback in the chassis as a replacement i.e a 10inch flyback in a 20 inch chassis
you can check this by cross referencing the flyback part number which will be printed on the body
another option is to repair the swallow amusements chassis as that fault may be more simple to put right

[Nipedley]

You might be right, the tech who worked on this cab last was a jackass (He converted it to jamma and ripped the top monitor out, leaving a rather unsightly hole that he selotaped some plexi onto so people couldnt stick their hands in! Who would want to play a cab like that?!)

I'll check out the transistors and the flyback no. tomorrow (bit dark now - spiders )

The problem with the swallow amusements' chassis was it worked fine, I took it out to swap the yoke plug (had it in the mirror-option) then plugged it back in, boom no picture! Rather random.. I'll take a look at that tomorrow as well see if I can find any cold solder joints or anything about..

[Rickn]

Sorry I did not catch this earlier. Unless I read the thread too fast and mssied something?

100% not TDA 1670/1675, these are vertical outputs and you would have vertical collapse.

Not Flyback, you have picture.

Transistors??

Looks like you have an image, is that a multiple image, meaning same image side by side, is it stable verticaly??

If so we have wrong res monitor for what the game is set to.

I do not know anything about Hantarex, but ...

Good luck

Rick Nieman
Rick@Niemandisplays.com
www.niemandisplays.com

[Nipedley]

Hey Rick! Thanks for replying, I've seen your posts about the forums before and they're always very insightful

It is a standard res monitor and a standard res game, the image is perfect in every way except it scrolls from top to bottom, top to bottom.. and it never ends!

I have exactly the same problem now as when I picked it up 2 years ago (trying to fix it since), none of the repairs fixed the sync problem but at least the image is much prettier now

My avatar is from one of the monitor's better days.. but it never lasts more than 10 seconds before it starts scrolling again.

[Rickn]

Ok grant was on the right track with connections- and as he knows Hantarex and I do not- I trust your connections are right??

So let's start from scratch.

Ok from cold you power up, what do you get? Did I understand that after a while it loses sync, or does it never have it.

So did you ever have this game operational and in good sync?

We need to weed things out, so do you have anyother games at standard res any other monitors that we can use to subtitute and rule out game or monitor or connections??

Hey Grant, if you are watching and have a schematic for this could you e-meil me it or point me to it.

Thx Rick

[Nipedley]

Connections are all good, tried every combination possible really.

It never has vertical sync, horizontal is perfect. As soon as its turned on it will start scrolling, best I can do is adjust with the v-hold pot for a few seconds before it starts off again. It's always been this way..

I've 4 different game boards all of which have the same symptoms which work fine on my wells gardner k7000, so it's definitely a problem with this monitor chassis.

Schematic can be found here in the manual; http://www.mega-play.co.uk/manuals/mon_rc_mtc9000.pdf

I've been trying to understand and fix this thing for 2 years so far! Not having much luck as you can see

[grantspain]

hey rick here's a link to the schems http://www.freeinfosociety.com/electronics/schempage.php?cat=10
i worked on loads of these chassis in the late 80's but i was just a kid so i don't remember all the problems,one thing i mentioned earlier was a problem when techs swapped out the flyback but got the wrong voltage flyback-i know that when you replaced a 10" flyback with a 20" then the monitor would shut down as the tube was getting far too much eht but i don't remember the opposite happening
the strange thing with this particular fault is the fact it seems to lock on power up and then looses vertical sync
my guess is one the transistors crapping out
its an obscure fault to say the least

[Rickn]

So the problem is most likely IC 2 or components in front of it.

Play with SW4.

If you have an oscilloscope this would be a whole lot simpler.

This should be an easy fix for a local TV shop.

It may have been mentioned, but is the game Composite sync (5 wires R,G,B, GND, Sync) or separate (6 wires R,G,B, Gnd, Horiz, Vert)

Rick

[Nipedley]

Just replaced IC 2 yesterday with no luck. What other components could be at fault?

I already tried the local tv shop, but because its not a "tv" they blank-out refused it.

This game's composite sync, just like the connector on the chassis

A huge thank you to you both (and everyone else through the years!) for trying to help out with this darned thing.
Quite tempted to blame it on the gremlins

[Rickn]

So you did play with SW4??

This switch changes it from composite to separate sync.

Rick

[Nipedley]

It's too dark/late (midnight!) for me to mess around right now, I'm going to test this stuff out tomorrow

The only switch I'm aware of on my model MTC9000 is a switch to change from positive to negative sync, which I have played with before and only ends up with a giant mess on the screen 

Tomorrow I plan to test out the transistors, and check out the flyback number just to make sure

[Nipedley]

Madness. I figured I'd try out grant's advice and take a look over the alternate chassis I purchased last year, found a few cold solder joints and whoila we have a picture (which doesnt roll like crazy!) only problem now is the picture is ultra-blue.. Unfortunately there only seems to be a red and green gain control on the neckboard?!

Gawd these hantarex monitors are weird. (Also an mtc 9000 chassis by the way).

There is a blue cut off pot on the neckboard but I've heard those arent for playing with, so if its not that pot and there isnt a blue gain one then how do I make my monitor have normal colours?

My oh my..

ADD: I pulled the monitor just now (cant access neckboard from cabinet without pullign the whole lot out I'm afraid) and set the red and green gain pots to half each, but with no noticeable change. Still a huge blue tint. Any suggestions?

ADD2: So I got bored and tried setting R +G gain to full and to zero, and nothing! Still major blue tint. I guess that means I probably have a faulty blue transistor? Sighs..

[SirPeale]

There is a blue cut off pot on the neckboard but I've heard those arent for playing with...

Of course you can play with them.  See what it does.

[Nipedley]

I heard a few years ago it was to do with voltage and 'dont touch!' but I just had a go anyway. I found the Blue gain control (hidden and not in the manual?) with no change, and changed the blue drive control so it matched the others and the picture is still blue as ever. Seems to have a couple of blue retrace lines at the top of the screen now as well.

Since the controls havent seemed to help this whatsoever, can I assume it's a transistor issue?

[grantspain]

good chance the blue drive transistor is leaky,this is a common fault on all hantarex range-swap out one from the other chassis

[Nipedley]

Thanks grant I'll have a go with this probably next weekend, at least she is playable now just a little bit blue

Might order up a cap kit as well. Nice to know things are finally on track!

[Nipedley]

I'm checking out the 'sync problem' chassis just to see if I can find the problem.. I can't see any numbers on the flyback? There's a logo that says Diemen Spain HR on it, but thats about all I can make out?

When checking transistors, did you mean the ones on the board or the neckboard?

Also, I've ordered a new transistor for the 'blue' chassis because once again the parts on my 'sync' chassis dont match up to it. The 'sync' chassis has BF850 transistors while the 'blue' chassis has BF450...

[grantspain]

the chassis with the blue drive fault check and change tr203 on the neck card,if you still have a blue problem then check tr1,2 and 3 on the main chassis
just take the tr203 from the sync chassis and swap it onto tr203 on the blue chassis
the the flyback will have numbers embossed on the side of the body,it can be difficult to see
don't worry about the transistor difference as they are probably exactly the same

[grantspain]

after checking some notes i made millions of years ago in respect to sinc problems on mtc9000 i found the following.
check t110 and 112
replace c149,150
replace ic104
if all checks out and you are using seperate sinc inputs use a 10k or 5k resistor on the vertical sinc to ground
if you go back to the sinc problem chassis maybe these notes cab help

[Nipedley]

Thanks grant, I have a crap load of replacement parts in the mail (damn postage strikes!) Once they arrive, I can replace the transistors on the 'blue' chassis and fully re-cap it, and at the same time then I'll go through the check list for the sync chassis.

Everything I've ordered before, next day delivery. Been waiting a week now because of royal mail!

[Nipedley]

Right after 2 deliveries each taking well over a week of the wrong component I finally caved in and swapped over the BF859 from the 'sync' chassis and huzzah the blue problem is gone, it now looks great. After some extensive play-testing () I then discovered it has a horrific static sound, almost like it's going to explode. But the picture looks absolutely fine. Am I just worrying too much or is something amiss here?

This is with the back of the cabinet off, so maybe that's why the sound is so prominent but I wouldn't like to finish it off and stick it in the corner only for another component to go next week or something.

[Nipedley]

Just thought I'd ask, while working on the 'sync' chassis some more earlier (I was bored) I noticed that the mains smoothing cap was of the wrong value, 330uF instead of 470uF. It had been replaced by another tech, is that alright or would that potentially cause problems - even the sync problems?

Following the sync signal throughout the entire board and replacing every dodgy component along the way as a last measure