Neotec NT-2700

[Djsniperwolf]

I have a Neotec NT-2700 that is continually blowing it’s HOT. Fortunately, I have some background info that I hope will allow someone to point me in the right direction.

CRT was plugged into a MAMe cab through a JPAC with 15khz dip switch set. I believe this was done on a retro-pi, which is something I never messed with. He proceeded to book up a rom image of mortal kombat. He then proceeded to attempt to change the resolution of the game.

I guess the image got really bad or distorted, made a sort of whining noise before shutting off. I bought the monitor from him as it sounded like a HOT issue. Replaced it and it immediate blew on me on power Up.

With this information, Is there any info someon can provide on where to look or what to do? I am by no means savvy, but I have done cap replacements and Such.

Thanks!!

[R_J]

Re: Neotec NT-2700

If the horz. output is blowing, check the components in the base circut IE: R426 & L401. if they are ok, check for any shorted diodes off the flyback, like D502, also check the drive transistor, Q401.

[Djsniperwolf]

Re: Neotec NT-2700

If the horz. output is blowing, check the components in the base circut IE: R426 & L401. if they are ok, check for any shorted diodes off the flyback, like D502, also check the drive transistor, Q401.

Perfect, thanks for pointing me in the right direction. I will check those circuits.

Something else interesting, I noticed the HOT was arcing with the screw that mounts it in place. I have the mica pad and paste in place which I find odd. I may order a new insulator, plastic washer, paste, and screw to be proactive.

[R_J]

Re: Neotec NT-2700

Which transistor are you using? 2SC4542 has two styles, one is all plastic and needs no insulator and one needs the insulator but the screw should already be insulated from the transistor

[Djsniperwolf]

Re: Neotec NT-2700

Which transistor are you using? 2SC4542 has two styles, one is all plastic and needs no insulator and one needs the insulator but the screw should already be insulated from the transistor

Crap, you're right. It is uninsulated... could that have been the issue?? Okay.. need to seek out the insulated HOT right away. I'll still do some inspections on the board to make sure the arcing didn't fry anything.

And recommendations on where to source an insulated 2SC4542? Thanks a ton for pointing that out.

[R_J]

Re: Neotec NT-2700

If the heatsink is grounded, and the transistor tab is exposed metal (it is connected to the collector) it must be insulated. I don't know where to get these parts anymore, most places like digikey etc. no longer carry them. A 2SC4747 is also a substitute.