Hantarex polo star keeps blowing HOT

[MKL]

That transistor looks suspicious to me. I have quite a few of them, all pulled from TVs so I know they're authentic, and they don't have that kind of "label" on them. All the markings are engraved on the main body:

Yours looks like the fake ones pointed out here:

http://forums.arcade-museum.com/showthread.php?t=326880

Considering these are used on some WG monitors I totally believe there are a lot of fake ones around esp. on ebay. I hope yours is legit but wouldn't be surprised if it's not.

 

[TimRose]

Holy sh*t I just checked the original ones I removed and they are both flat print as well =/ how do I know if the ones I have a fake or real then?

 

[tb2000]

I'm not so sure, I've got chassis with 2sc5144 the same as that and they were fitted probably many years ago, so unless the!fakes were around years ago (possible) then I'd say it could be authentic.

 

[Judder]

Not my area of expertise but reading around there some good HOT check list of things that cause them to blow/short here

http://www.bestelectronicarticles.com/consumer-electronics/crt-televisions/how-to-prevent-the-horizontal-output-transistor-h-o-t-from-getting-shorted-after-replacement.html

I was intrigued, so Googled the phone number in the contact page and they're in Kenya - guess there's still lots of CRT TVs out there!

 

[TimRose]

Just had a read of that and I'd does make a half decent read, some good tips. I have emailed randy Fromm last night because I want his big blue book.

 

[Judder]

Just had a read of that and I'd does make a half decent read, some good tips.

Yes it's pretty good (good old Humphrey!) and I was a bit bored on the ferry to Ireland so read some more good tips below which should also help (I have a couple of monitors I need to fix too so also reading up for that!)

Apparently HOT vary from manufacturer to manufacturer and batch to batch!

http://www.repairfaq.org/sam/deflfaq.htm#dshot

 

[TimRose]

Can i replace a polypropylene cap with a film capacitor? The values are the same and I have seen other monitors with them fitted but is there a difference I'm missing?

 

[TimRose]

I took a gamble with it and it works the monitor lives!!! Muhaha. I feel great, what a weight lifted. Thanks guys you have all been top helps.
It's just got one small issue, but if I have to start a new thread just tell me.

I have no keystone, pincushion or horizontal width adjustment. I have horizontal shift, but that's it.

The pictures good it's just stretched out and curved right out. I have tried another e/w board and it's the same so that eliminates that. Anybody had this before?

 

[TimRose]

I've tried the post on the e/w board which shifts the image left and right. That's it, I could adjust the width coil which would make the image smaller but I don't think that's at fault here.
I have removed my controls board extention lead and swapped the controls board itself. None of which cure it. So the fault must be something on the main board.

Sods law that my schematic seems to be missing a strip between the 2 pages which shows you the pincushion circuit.

 

[TimRose]

OK last post of the night, read online about some pincusion correction diodes near the hot and what do you know, one tested 0 volt drop in both forward and reverse diode. So I pinched one from my other chassis and it tested good, now I get this, complete reverse symptom, still no controls but now everything is squished.
Sack this I'm going to bed....

 

[TimRose]

Problem solved, so for anyone else who looses cushion and width control, after changing the diodes right next to the HOT, if you encounter a shrunken screen like above, I found that the resistor right next to the horizontal width coil (r135 I think) was oc, replaced with a spare 10r and problem solved. Hope this helps