Olevia LT37HVS - power prolems, caps related?

[GLDIVER]

Greetings.

I have an Olevia LCD HDTV model LT37HVS. Set turns on and works for 20 to 60 minutes then makes a bit of a crackling sound and goes dead. No sound, no picture, no blue logo light on front. If unplugged for 30 seconds, then plugged back in, it again works perfect for 20 to 60 minutes and the cycle repeats itself. Since it goes completely dead as opposed to just losing sound or picture I suspect the problem lies in the power supply. During my research I've found a lot of information that bad capacitors can cause nasty problems. I'm wondering if this sounds like it could be capacitors in the power supply (Arestech AEP001-24 REV:1)? To my completely untrained brain it seem to be something very early in the power supply like a transformer since when it goes out EVERYthing goes dead.

Thank you in advance for your time, attention and insight. It is much appreciated.

Jeff,

[selldoor]

Re: Olevia LT37HVS - power prolems, caps related?

You need to take the back off the set and establish where the crackle comes from.

Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

It will be useful if you can say what the supposed fault was and a bit about yourself - skills tools etc.

[GLDIVER]

Re: Olevia LT37HVS - power prolems, caps related?

Hello selldoor and thank you for the quick reply.

The crackle sound comes through the speakers. I have already tore into the set and pulled the power supply so I'm too late to listen if there is an actual crackle coming from a particular area of the set. I think it's just static from whatever it is that's knocking out the power. I can take photos of the power supply which I'm pretty sure is the culprit since everything goes dead at once. I'll do that after I finish with work

While I do not have much experience with TV's, I have worked with computers (desk tops & laptops) since the 80's. Upgrading ram, modems, replacing LCD screens - who knew they cracked so easily - and such. Basically I'm 1/2 too cheap to pay someone else to do it, and 1/2 to interested in ripping it apart and seeing what makes it tick. I have a basement full of tools though my wife keeps "cleaning up" and I can't find them most of the time. I pretty much have no fear of ripping something apart. Which is both a blessing and a curse....

Thanks again for the reply, your time is appreciated!
Jeff,

[GLDIVER]

Re: Olevia LT37HVS - power prolems, caps related?

Ok... I've attempted to photograph the power supply board. Due to it's size I did the front in 3 sections. I've looked it over quite carefully on both sides and see nothing out of the ordinary. All the caps look good, no bloating or leaking. Nothing looks to have ever been hot. I don't see any "smoking" guns, at least to my untrained eye. Since everything goes dead it seems to me it's power supply related. I suppose there could be another board causing a problem that in turn kicks out the power supply, I just don't know. I can get a new power supply for $40 or change out the caps for $15. But I just don't have any confidence that either will cure the problem.

Small Caps are: elite brand
Mid size Caps are: Ltec brand

If you see anything I didn't or have any suggestions I'd love to hear them.

Thanks for your time!
Jeff,

[infringer]

Re: Olevia LT37HVS - power prolems, caps related?

If anything I would say 40bux is not bad at all for a power supply and in this case it sounds like it is something on your power supply being that it is going completely dead...

But if you want to save a few bux may want to wait for further advice.

[mockingbird]

Re: Olevia LT37HVS - power prolems, caps related?

Does the logic board have solid-state or electrolytic caps?

[budm]

Re: Olevia LT37HVS - power prolems, caps related?

This power supply has PFC circuits (in the third picture), 5v standby (picture #2 top section small transformer), switched 12 or18V power supply (middle section transformer), switched 24V power supply (bottom transformer).
So right now you are not getting any indicator lights on the front of the TV at all, if that is the case, the standby power supply may be bad or the main board is completely dead.
Check the DC voltage at that 450Vdc DC main filter cap (this is the Line voltage primary circuits so be real careful), it should have about 170Vdc (if the AC in put is 120Vac) WITHOUT the TV ON, if it does, then check and see you do have the 5Vdc from the 5V standby power supply section.
Just make sure NOT TO TOUCH any parts of the Primary circuits, you should have this TV plugged into GFI outlet to protect yourself.

[GLDIVER]

Re: Olevia LT37HVS - power prolems, caps related?

Thanks for the quick replies gentlemen.

infringer: I agree, $40 is a cheap power supply. Most want $60 to $80 for it, but I found a site that has it for $39.95 with free 2 day shipping.

mockingbird: I'm not sure which is the logic board, or what a solid state cap looks like, sorry.

budm, At last use before tearing it apart the set would power up and work perfect for between 20 and 60 minutes after that it would just go dead. No sound, picture or blue logo light at front. After unplugging it for 30 seconds it would again start up perfect for a while and the cycle would repeat. Can the power supply voltages you mentioned be tested with the power supply out of the set? I know some things don't like to be plugged in when there's no draw on them.

I'm a little curious what exactly it is that gets "reset" when unplugged for 30 seconds. Is there some type of circuit breaker in there somewhere that resets? Or is it just something cooling during that short period of time? Or is just rebooting it enough to get it to work for a short while?

Thanks again for the help. It is much appreciated!
Jeff,

[mockingbird]

Re: Olevia LT37HVS - power prolems, caps related?

mockingbird: I'm not sure which is the logic board, or what a solid state cap looks like, sorry.

The logic board is the board with the lcd driver chip and whatnot. LCD TVs should have four boards if I'm not mistaken. PSU, Logic, Inverter (Which should be part of the screen), and tuner.

Since it's an Olevia, which is considered an off-brand, you should check to see if you also need to change the caps on the logic board. Can you post another pic?

[selldoor]

Re: Olevia LT37HVS - power prolems, caps related?

I would try the hairdryer test. While the set is on warm firstly the power board with a hairdryer to try and get it to go off quicker. If that doesnt make ant difference try on other boards. Then if you establish a board try and narrow it down to a section.

[bmc763]

Re: Olevia LT37HVS - power prolems, caps related?

Thanks for the quick replies gentlemen.

infringer: I agree, $40 is a cheap power supply. Most want $60 to $80 for it, but I found a site that has it for $39.95 with free 2 day shipping.

mockingbird: I'm not sure which is the logic board, or what a solid state cap looks like, sorry.

budm, At last use before tearing it apart the set would power up and work perfect for between 20 and 60 minutes after that it would just go dead. No sound, picture or blue logo light at front. After unplugging it for 30 seconds it would again start up perfect for a while and the cycle would repeat. Can the power supply voltages you mentioned be tested with the power supply out of the set? I know some things don't like to be plugged in when there's no draw on them.

I'm a little curious what exactly it is that gets "reset" when unplugged for 30 seconds. Is there some type of circuit breaker in there somewhere that resets? Or is it just something cooling during that short period of time? Or is just rebooting it enough to get it to work for a short while?

Thanks again for the help. It is much appreciated!
Jeff,

How did you make out with the new power supply , did it do the trick? I am having the same problem, unit has been great for 6 years and bang dead after a couple of weeks of erratic shutting off, wouldn't turn back on until I unplugged it and then it just wouldn't power up one time !

Where did you find the supply for $39.99 with 2 day free ship? I may need to buy one from the sounds of it !
Thanks

[azdave35]

Re: Olevia LT37HVS - power prolems, caps related?

i have the same tv and had similar problems...i replaced the caps on the power supply and it didnt help..i used a hair dryer on the main board and found the bad caps..i replaced them and it fixed the problem....before you replace the power supply check the caps on the main board

[bmc763]

Re: Olevia LT37HVS - power prolems, caps related?

Replaced the power supply for about $45 and TV is brand new..

[Taterbug]

Re: Olevia LT37HVS - power prolems, caps related?

Which caps were replaced on the main board?

[selldoor]

Re: Olevia LT37HVS - power prolems, caps related?

Man, this is some old thread! Post pictures of your boards and also try the hairdryer trick.