Hyundai HLT-3270 Dead!

[netdent]

Looking at this for a friend, fairly old tv but might be worth saving, anyway it is dead no standy light and no voltages coming out of the psu, can hear the hv on the mains side which pulses every 20 seconds or so

I see there is a repair kit for this board which is BP-170AWL but the symptoms are blown fuse which this has not, checked for cold solder jpints etc, seems a hot spot around the 2 resistors in the centre? anyone any pointers? where to start?

thanks Ronnie

[selldoor]

Re: Hyundai HLT-3270 Dead!

Hi, we are probably all waiting for a picture of the back of the power board and a close up of the other side of the singed section.
My initial reaction is - is that little cap in the middle of it cooked and is that the startup cap? - cant find a schematic. I think i'd just replace it anyway.

Have you tested for power across the BIG Cap -High voltage so great care- meter on 600DC and observe the polarity.

Did you test the out voltages with the other boards connected?

[netdent]

Re: Hyundai HLT-3270 Dead!

Hi, we are probably all waiting for a picture of the back of the power board and a close up of the other side of the singed section.
My initial reaction is - is that little cap in the middle of it cooked and is that the startup cap? - cant find a schematic. I think i'd just replace it anyway.

Have you tested for power across the BIG Cap -High voltage so great care- meter on 600DC and observe the polarity.

Did you test the out voltages with the other boards connected?

Thanks for the reply selldoor.

I tested for voltages both ways plugged and unplugged, seems dead on the output plugs no 5v, I measured across the big cap varying from 411v to 422v on DC, more pics added, the cap you mention I think is the one I circled red? it looks normal not changed it yet 35v 1000uf

thanks Ronnie

[selldoor]

Re: Hyundai HLT-3270 Dead!

Hi - still cant find any data on this power board. Perhaps try and test the
components listed in the repair kit. Its good that they give the part no and description- perhaps cost up how much to buy separately.

[netdent]

Re: Hyundai HLT-3270 Dead!

Hi - still cant find any data on this power board. Perhaps try and test the
components listed in the repair kit. Its good that they give the part no and description- perhaps cost up how much to buy separately.

Thanks again, will have a look
Ronnie

[Kingspin]

Re: Hyundai HLT-3270 Dead!

When you get one of these sets dead with the fuse on the power board intact the first thing to do is replace all primary side electrolytics , that includes the big mains filter capacitor , these caps live a hard life and often are found to have gone high esr. The next thing to do after changing the electrolytics is to check the 2 schottky diodes on the heat sink secondary side , often 1 or both will have a short. Should you still have no luck getting the psu to start then consider a reclaimed board. The thing is it could be quicker and simpler than a rebuild of the psu , they can be time consuming to get a successfull repair these psu's so don't say i didn't warn you! Please Check all heat sink mounted components carefully for shorts/ leaks.
I hope this helps anyone contending with one of these little psu devils..

[Kingspin]

Re: Hyundai HLT-3270 Dead!

I forgot to mention replace all of the electrolytics on the secondary filter side too, they are poor quality and often fail. The 2 schottky diodes on the secondary side are very hard
to obtain , use a MBRF20H150CT this is a 20a 150v dual type it will need an insulating pad though as the original fitted is an insulated case schottky.

[tom66]

Re: Hyundai HLT-3270 Dead!

I used a 150V, 16A schottky on my set with a mica spacer and thermal paste. Do not skimp on the thermal paste!

[cyberkul]

Re: Hyundai HLT-3270 Dead!

I forgot to mention replace all of the electrolytics on the secondary filter side too, they are poor quality and often fail. The 2 schottky diodes on the secondary side are very hard
to obtain , use a MBRF20H150CT this is a 20a 150v dual type it will need an insulating pad though as the original fitted is an insulated case schottky.

Hi! I`m trying to repair one of these. Today I removed all the electrolytics, and found three of the small ones to be bad. Maybe some of the others too, but they were at least close to the correct capacity. One of the Schottkys is shorted. The two are not the same. The shorted one is a MBR20150FCT, and the other one is a MBRF20H100CTG. I found MBRF20H100CT, and MBR20150CT at Farnell.com Not sure what the difference between the originals and these are. Just an "G" and a "F" differs..

Did you mean that the one you suggested in the above post can be used as a replacement for both the originals?

Gunnar

[tom66]

Re: Hyundai HLT-3270 Dead!

I fixed this set and successfully used the 16A, 150V Multicomp diode that Farnell sells... still going strong in kitchen.

[cyberkul]

Re: Hyundai HLT-3270 Dead!

I fixed this set and successfully used the 16A, 150V Multicomp diode that Farnell sells... still going strong in kitchen.

Thanks! I`m starting to believe that I can fix this set!

[tom66]

Re: Hyundai HLT-3270 Dead!

Bear in mind mine had been attempted repair before, the guy had used the wrong diode and was shorting the PSU out, causing it to shut down, was a nice easy fix

[cyberkul]

Re: Hyundai HLT-3270 Dead!

Wrong schottky?

[tom66]

Re: Hyundai HLT-3270 Dead!

Completely the wrong device. Used a device with a designed-in short between pins 1 and 3. Looked like some ancient device from a 70's VCR! I noticed pretty quick after pulling the board out it didn't look right. It had a diagram printed on it showing the short between 1 and 3, as it was a single diode, not dual type. Also, there was no heat pad (mica spacer) and no thermal paste (unlike one for the 12V output, which was factory original), so if it had somehow worked, then it would have burnt up very quickly and failed again.

[cyberkul]

Re: Hyundai HLT-3270 Dead!

Hehe.. hopefully I`ll do better :-)

[cyberkul]

Re: Hyundai HLT-3270 Dead!

Just to let you know that the repair was a success :-)
Replaced all el. caps, and both schottkys. Set has been running fine the last month.

Gunnar

[tom66]

Re: Hyundai HLT-3270 Dead!

Nice to hear -- mine has been playing in the kitchen every other night when the fellow students watch movies, no problem. I don't like the picture quality one bit but it does OK for the occasional thing.

[Techstar]

Re: Hyundai HLT-3270 Dead!

Bear in mind mine had been attempted repair before, the guy had used the wrong diode and was shorting the PSU out, causing it to shut down, was a nice easy fix

I know the guy who supllied the diode was a complete idiot , it was purchased from a shop at stocksbridge sheffield as i know the repairer. Note , the service engineer should have checked the supplied diode was correct, all done in haste is a waste. Lesson learned for all. The guy in the shop who sold the diode got a right telling off!