Hantarex MTC 900e problem

[gridrunner]

Hello Chaps,

The MTC 900e in my puckman lasted a whole 4 weeks before crapping out. It's lost vertical sync. The picture had some tearing initially and intermitent sync with a rolling field, now it's down to rolling vertical/squashed lines and no field.

Can anyone provide pointers on likely suspects?

thanks

 

[karlcdoe]

I rather presume you have tried to adjust the sync?

 

[karlcdoe]

anyhow, assuming you have checked that the roll can't be adjusted out I see the manual appears to be here: http://www.arcade-museum.com/manuals-monitors/Hantarex%20MTC900E%20Service%20Manual.pdf

I must state first that I have yet to bother fixing any of my hantarex monitors but I would start by checking for a good connection between the sync output(s) on the board and the monitor. Then check for cracked solder joints on the green hantarex connector (I did have one like this that caused a sync problem). Then I'd probably check the pot isn't 'dirty' and pull out my scope and try to confirm some of the waveforms make sense coming from the TDA2593 IC , they are detailed on page 13 in the manual.
If you don't have a scope then I'm sure there are some repair logs for hantarex monitors online somewhere, not sure of the exact models but it'll probably give an indication of common failure points. I'd then use that + the schematics to see what supporting circuitry lies around the sync circuit resistors/diodes/capacitors, etc and visually check them for burning, and then start pulling them and testing them with a multimeter. You could shotgun replace them if the parts are cheap/easy to find.

 

[gridrunner]

Hi Karl,

I've taken the chassis out to re-flow the connector solder joints and I'll change the caps in the vertical deflection circuit while I'm at it. I'll re-fit and try adjusting the sync if it won't hold. The tearing and instability made me think capacitor initially, but now the sync is completely gone.

 

[karlcdoe]

Hi, sorry I couldn't think of anythign more specific to check...

 

[Guests]

im guessing its an Italian/euro 900e?

have you tested the monitor with another pcb just to make sure its not a board fault/bad wiring?

i would pull the diodes TR1 to TR4 on the chassis and test/replace then work your way back on the sync circuit

Connors2012-04-17 16:13:04

 

[gridrunner]

Hi all,
swapping out caps in the vertical circuit cured this problem.

Caps are:

C32 2.2uf 63v

C33 1000uf 35v

C98 100uf 16v

C60 2200uf 16v

C55 10uf 25v

 

[Level42]

im guessing its an Italian/euro 900e?

Weren't all e's meant for the US ? I thought the 900 without E was the model for Europe, think someone mentioned E stood for Export ?

 

[PaulSwan]

900e is the next evolution above the 900. The 900e/USA is the one that was put in US cabs. The only significant difference is that the e/USA has a US-style single-supply monitor power plug and the degausing is on the 120V supply (AFAIK standard E's have a Hantarex power connector and a separate supply (240V?) for the degausing).

Paul.