MTC900 no neck glow

[Togsodar]

So, Ive got a Chase HQ with an MTC 900 which has no neck glow, I found a couple of resistors that had come disconnected from the power supply and fixed those but still nothing. I can hear a faint crackle from the chassis when I connect the power. Ive had a play with the neckboard which although has a crack all the way across as far as i can see its been fixed and should work ok.

Here's a photo of the chassis, can someone point me in the direction of possible causes, common faults and where the HOT is located on this chassis.

Many Thanks.

 

[tb2000]

Ok, well for starters that's a MTC900/E, not a MTC900 which is the chassis prior to this one and somewhat different in circuit design!

The HOT is the BU208 transistor screwed to the metal upright heatsink on the right on the chassis (nearest the lopt/flyback). It may have a plastic safety cover over it. If you get a crackle it sounds like you have HV, so I wouldn't think there's much wrong with the HOT. If you have no heater then you need to trace it back to the chassis. There's not much in the heater circuit to go wrong really, there's a slight possibility that your lopt/flyback has failed.

 

[Togsodar]

Many Thanks for your reply tb2000

Ah now i thought orignally it was a mtc 900E I should learn to go with my first instincts

Is there any way of testing the lopt/flyback with a multimeter to check if its working or is it just worth replacing if still available?

And forgive my ignorance but is that the black box on the bottom right

 

[tb2000]

The only thing you can test with a multimeter on the lopt is whether the windings still have continuity and that they aren't shorted to each other. MTC900/E lopts were fairly sturdy (when compared to MTC9000 or Polo lopts) but I have replaced a few lately due to shorted windings and also worn out/broken focus controls. To be honest, the only way to properly test is to compare to a new one. They are still available. I have some but i'd prefer to keep them for repairs. Try messaging gunblade, he may have one spare that he's willing to sell. and yes it is indeed the black box on the bottom right, with the anode lead with the rubber cup on the end! Even if yours is fine, is worthwhile having a spare in case yours does go faulty at some point.

 

[Togsodar]

Thanks tb2000 i think ill replace it if they're not too horrendous.