Hantarex mtc900e smoking.
- Thread starter Oggyuk
- Start date
Retroman839
Senior Member
If it got really hot
Your flyback is probebly shorted internally ..
Mine did it on a cab and it was a lot of smoke ..
You would need a new flyback .
Maybe you can visually see a crack in the flyback or smell your flyback has burned up?
Replacing the Bu208a will just blow it again .
You need to find the underlying cause,
Ai says
Check the high-voltage polyester snubber/tuning capacitor sitting right next to TR15. If this cap drops in value or cracks open, it can no longer filter out the massive voltage spikes generated by the yoke and flyback, instantly punching a hole through your new BU208A transistor.
Your flyback is probebly shorted internally ..
Mine did it on a cab and it was a lot of smoke ..
You would need a new flyback .
Maybe you can visually see a crack in the flyback or smell your flyback has burned up?
Replacing the Bu208a will just blow it again .
You need to find the underlying cause,
Ai says
Check the high-voltage polyester snubber/tuning capacitor sitting right next to TR15. If this cap drops in value or cracks open, it can no longer filter out the massive voltage spikes generated by the yoke and flyback, instantly punching a hole through your new BU208A transistor.
Retroman839
Senior Member
I was replacing hots from Fairchild
Importing Fairchild transistors from usa at £40 a pop ..
Just to blow them instantly on a pf
29”
That sucked.. I hope you can find the
Reason why you’re hot is blown.
I would check that snubber
And check flyback
Before fitting a new hot just for it to blow
Importing Fairchild transistors from usa at £40 a pop ..
Just to blow them instantly on a pf
29”
That sucked.. I hope you can find the
Reason why you’re hot is blown.
I would check that snubber
And check flyback
Before fitting a new hot just for it to blow
Last edited:
The wobbly image is either the degauss ptc stuck on or the power regulation circuitry not working. Check the B+ for 126v. If it's not 126v or it's not adjustable you need to fix that part. Also, if you haven't already, change the three small caps out at C25, C36 and C83 (these can cause picture brightness problems), all are at the rear of the RGB interface/psu board. I don't see a red convergance issue, but it does look a bit like it's overdriven. Knock the red drive or cutoff on the neckboard down a bit. The positioning problem looks like maybe a sync issue. I'd check the small BC transistor in the sync circuit first at TR1. It'll be either a BC237 or a BC547.
Thanks, will have go at these.
I have 128v at B+, caps C25,C36 and C83 have been replaced. tweaked the red down a lot. not looked at TR1 yet
Retroman839
Senior Member
pic looks to big ?
Is it def right chasiss for screen size ?
Is it def right chasiss for screen size ?
Retroman839
Senior Member
it looks pretty wide that
Wider I would say than my
Mtc900E goes on a
20” tube. Which is most likely less naturally on a bigger tube I understand that ..
Is this a 19” tube ?
Wider I would say than my
Mtc900E goes on a
20” tube. Which is most likely less naturally on a bigger tube I understand that ..
Is this a 19” tube ?
Depends on your definition of 19" or 20". Sometimes people say 19", sometimes 20". Though technically a 19" is an A46 crt. If it's an A48 crt or, if Videocolor, an A51-421X for example, then it should be fine. The problem here is with the chassis image adjustments, or B+ being a problem. Or possibly caps etc.
Retroman839
Senior Member
Yeh ..
I’m Just curious if that width is going to dial in/ or remain to wide ?
Like enough to fill a 22 or 26” ?