Samsung HL67A750 DLP with bad caps!

[mb3df]

Re: Samsung HL67A750 DLP with bad caps!

Hi, I just found this thread and joined the site. Can you share with me where you found a replacement LED driver board. I've been looking around online everwhere and can't locate one. It would be a shame to have to junk an otherwise good tv 'cause Samsung does not support its product.

[Tiezane]

Re: Samsung HL67A750 DLP with bad caps!

Just sent you a PM with the info.

[Woodfighter]

Re: Samsung HL67A750 DLP with bad caps!

Tiezane,

I am having the same issues with my Samsung HL67. Could you tell me where you found a LED driver board?

[LLLlllou]

Re: Samsung HL67A750 DLP with bad caps!

Poor thing. Samwha are not very good. Time to replace all of them not just the vented ones. It's not so much diameter that is important, but ESR and ripple ratings. You want the ESR to be the same or slightly lower, and the ripple rating to be the same or higher. I would use Panasonic FC, nichicon PW, Chemi-con KY

Actually Samwha WB are VERY good, way better in specs than the FC PW or KY series. They're more the equivalent of the FM or KZM series. They also last quite a while. WB series supposedly went out of production in 1999! My TV was manufactured in 2007, so they sat in a box for at least 7 years, then worked in my TV for another 6 years. Only one was bloated, four out of the five still test within specs! That's better than most. Of course there's the "shame on Samsung" thing, for using 7 year old caps in a $3K TV, but at least they used decent old caps. There was actually a class action lawsuit that Samsung lost because of the old caps. The settlement just expired a few months ago.

I just replaced all five of the WBs in my hlt6187sx, I used Panasonic FR series. The 16x25 3300UF 25V ones not only have 10000 hour endurance rating, but they're one of the few series in this can size (the FM and the KZM, both in 2700uf are two others) that exceeds the WBs rated specs.

WB:
2200uf 25V 16x25 .015ohm 3.46A ripple

FR:
3300uf 25v 16x25 .014ohm 3.82A ripple

The extra capacitance should help steady the rail, those LEDs eat an ungodly amount of current.

While I had the TV open, I took the opportunity to replace all the rest of the caps under 200v as well. Mostly Capxon crap, KM and GS series, replaced with UCC KZE and KY respectively. BTW, the GS is an 85 degree series, and all still tested fine. If you know how to design a SMPS even old and crappy caps can last a long time.

The TV once again starts up like the day it was born.

[Tiezane]

Re: Samsung HL67A750 DLP with bad caps!

Tiezane,

I am having the same issues with my Samsung HL67. Could you tell me where you found a LED driver board?

I got it from www.skysearchersystems.com. The guy there had to order it from Samsung, they had to ship it to him then he turned around and shipped it to me. He's in Arizona, I'm in NC. When he ordered it, he ordered from Samsung's west coast warehouse, but they were out of stock, so they had to sent it from their east coast warehouse, out to him, then back to me. Probably took a little longer than it could have, but the guy there is great to work with, and the communication from them was really good.

still haven't had time/space to get into this TV more to find out where it's still failing. Some day....

[Woodfighter]

Re: Samsung HL67A750 DLP with bad caps!

Thanks for the info. I contacted the company via email but have not heard back from them yet. My guess is there are no more new BP94-02327A LED boards out there anymore.

The 4 bulging capacitors on the power board are what did in my LED driver board. Wished I would of notice them sooner, could avoided the problem by replacing 4 one dollar a piece capacitors!!!!

[Tiezane]

Re: Samsung HL67A750 DLP with bad caps!

Well, I finally gave up on finding time/space to repair this thing and sold it off I got a whopping $75 for it, but at least it's out of the way, and will soon be replaced with a Samsung UN65F6400, so while I'm sad to see the DLP go, I'm looking forward to the new addition

Thanks to everyone who helped troubleshoot this beast, I really wish I could have dedicated more time and resources to working on it, I have a definite respect for the engineers that created DLP, so many parts and so much to make everything work together... truly amazing.

[skyblaster]

Re: Samsung HL67A750 DLP with bad caps!

LLLlllou,

Thanks for your post. I have the same model RPTV and am now looking around for those FM 2700uF and FR 3300uF components. I recently replaced the DMD due to a few stuck mirrors and noticed three bulging WB series 2200uF caps on the sub power board while I had the back off the set.

I'm curious if you replaced any caps on the main power supply or just the SMPS?

Thanks!

[LLLlllou]

Re: Samsung HL67A750 DLP with bad caps!

LLLlllou,

Thanks for your post. I have the same model RPTV and am now looking around for those FM 2700uF and FR 3300uF components. I recently replaced the DMD due to a few stuck mirrors and noticed three bulging WB series 2200uF caps on the sub power board while I had the back off the set.

I'm curious if you replaced any caps on the main power supply or just the SMPS?

Thanks!

Sorry, I somehow missed your post till just now.

I replaced all < 200v caps on both PSU boards. The one cap I didn't replace, is a single big one on the main board. I knew I should have, but it looked like a major PITA to get the all the shielding off. Sure enough, less than 6 months later, and it's acting up again, I'm betting it's because of this one lousy cap. All I need is few hours of free time . . . that should take another year. I also need to do a pre-emptive recap on my dad's TV, probably another year before I get to that.

BTW, Digikey carries the FR series.

[skyblaster]

Re: Samsung HL67A750 DLP with bad caps!

Thanks for the reply LLLlllou!

I actually went ahead and purchased 2700uF FM series from Future Electronics since they were a good price. I didn't bother to replace any other caps.
Still need to source a reasonably priced 1910-6143W DMD since the one I replaced it with was no better than the original....bought used

[AlexW]

Re: Samsung HL67A750 DLP with bad caps!

Help!!!! I have replaced the led driver with the new one with the heat sink on it and I have replaced all of the bad caps. Tv will just turn on and try three times like all others... I tested the LEDS are tha 9volt and they all check out ok? Any advice would really help.

[the_pill]

Re: Samsung HL67A750 DLP with bad caps!

I have had this problem with my set for a few years, that's right i said YEARS. I power the tv on and no picture, sometimes I get the 3 blinking lights in the front, other times the set powers on, and no picture. When it powers on with no pic, I just leave it on for around 5-10 min, then turn it off and then back on and it starts right up. I think I'm going to just replace the sub power supply, and see if that totally fixes the issue. Anyone have any suggestions?

[Trips]

Re: Samsung HL67A750 DLP with bad caps!

Welp, I get to join the club now with you guys. Just experienced the "flashing lights issue" myself. And from what I have found thus far, this thread seems to have some of the better info I have found after searching for the last hour.

Sadly, I'm seeing that it appears to pretty fairly difficult to track down a replacement LED Driver Board. So I really hope that isn't the problem with my HL67A750.

I have been putting off replacing the DMD chip, as I only have 2 stuck mirrors for several months now. But I've noticed the last couple of times I turn the TV off, I hear an audible "short" sound. A slight "zap" if you will, yet the TV always fires right up. Disheartening to say the least, and I've expected something like this for a few months now. Alas, its here. Tonight I heard my UPS start beeping steadily. I power cycled it once, heard that familiar "short" sound, and when the AVR and TV powered back up, no picture, no dice, no bueno.

I have yet to try what "the_pill" mentioned worked for him, leaving it on for 15 min, then power cycling again to get it to display a picture. Will try that next as having the TV work while I source parts over the next week would be GREAT. Only TV in the house :-( . IN the meantime, I am going to do some more digging, testing, figure out where to start, and report back.

That said, how have some of you recent guys with this issue made out? Anyone that has been through this have anything insightful to add, or where I should begin?

Thanks in advance!

[MEM1971]

Re: Samsung HL67A750 DLP with bad caps!

I notice this model service manual and looks almost identical to my model HLT6187sx. Not able to find my model service manual and thinking its the same. Both are led dlp meaning no bulbs. only difference I see so far is the put a fan on main board and model in manual has ribbon cable from main board to dmd and mine uses regular dvi cable. Also not quite as many components on one in manual as mine has two reg coax v/s only the one in manual mentioned here. im thinking cause mine has analog and this one does not. parts are readily available for this one and not my hlt so much. Wonder if main board would work in mine. PSBs are the exact same thing and I like the fan this one has

[oysteroid]

Re: Samsung HL67A750 DLP with bad caps!

I've been working on a Samsung HLT6187SX/XAA for some weeks now. For quite a while, it has had problems when first powering on. The green light will blink once per second for a while, then go solid for a bit, then start blinking again. After a while, it might come on and display video but fail to respond to control requests, as if something is frozen. Or sometimes the sound is such that everything is maybe twice the normal pitch, making people sound like The Chipmunks. Other times, the audio is just a loud buzz. Or sometimes, audio is fine, but no picture. In most cases, after a minute or two, it resets itself and tries again. After a few resets, it tends to work fine. Once warmed up, it will go all day without problems.

Based on many things I read online, I thought for sure replacing the electrolytic caps in the power supply might help. I cracked it open and immediately saw a row of five swollen caps on the sub power board that feeds the LED driver board. I decided to replace ALL of the electrolytic caps on both the power boards, somewhere around 22 of them if I remember right. I also replaced the 1000uf 35V cap on the main board. I selected all Panasonic and Nichicon with better or equal specs on ESR and ripple current. I also replaced anything where the board looked a little brown from heat. So I replaced a handful of resistors with higher wattage versions, a couple of diodes, and a VIPER22ADIP-E low power offline switcher.

After replacing those, the TV behaved exactly the same way as before. No improvement. Once I got to looking more closely at the main board, I noticed a little surface mount component that was burnt and melted into a little ball, with a blacked area around it. It was next to one a cable header that connect to the DMD board. On the bottom of the board, on the row of pins for that header, I noticed two of the pins were bridged together with lots of solder. That explains the burnt component as this was a dead short of a 5V line. But the solder had to have been like that for the life of the TV and so probably had nothing to do with the power-on problems. This short prevented 5V from reaching the DMD board on one of the pins. I fixed it and replaced the burnt SMD ferrite bead and all the components near it, including a few little SMD capacitors, some resistors, and a zener diode. As I expected, that didn't fix the original problem. But I noticed that once warmed up, when I access the service menu, I have options that were missing or inaccessible before.

In my inexperience, I at first assumed that all those small cylindrical capacitors on the main, DMD, and LED driver boards were the solid polymer type. After more research, I realized that they might well be aluminum electrolytics. Since this thing improves when warm and since aluminum electrolytic capacitors have lower ESR when warm, I still think the problem might be related to capacitors. So I got an ESR meter and started testing those caps. I soon realized that testing them in-circuit is almost useless, as most of them are in parallel with other caps which lowers ESR reading dramatically. I desoldered a few to sample them and found some that had high ESR readings.

I am thinking of replacing all of the V-chip/SMD aluminum electrolytics that remain in this thing, about 140 of them, leaving the handful of green inked ones that are obviously polymers. It doesn't make too much sense to desolder all of them for testing, as it is hard to get these V-chip packages off without damaging them. To save some money, I was thinking of putting in Wurth capacitors in a regular radial leaded package and just bending the legs to fit the pads. Those are considerably cheaper than something like Panasonics in an SMD package.

What do you guys think? Should I do this, or should I just junk the TV? I am not sure what else to try here. I don't have an oscilloscope to see how clean the power is coming from the power boards, but I have voltages where they should be everywhere and all new caps on power supply. Actually, there are two pins on a cable connecting the power board to the main board that should have 16V according to service manual where I read 18V. Should I worry about that? I am not even sure my meter is accurate. It is a $30 Bosch automotive DMM. The thing is, this slightly high voltage is present when the thing is working great after warming up, so I don't suspect this has much to do with anything. I could be wrong!

[stanman2242]

Re: Samsung HL67A750 DLP with bad caps!

I've been working on a Samsung HLT6187SX/XAA for some weeks now. For quite a while, it has had problems when first powering on. The green light will blink once per second for a while, then go solid for a bit, then start blinking again. After a while, it might come on and display video but fail to respond to control requests, as if something is frozen. Or sometimes the sound is such that everything is maybe twice the normal pitch, making people sound like The Chipmunks. Other times, the audio is just a loud buzz. Or sometimes, audio is fine, but no picture. In most cases, after a minute or two, it resets itself and tries again. After a few resets, it tends to work fine. Once warmed up, it will go all day without problems.

Based on many things I read online, I thought for sure replacing the electrolytic caps in the power supply might help. I cracked it open and immediately saw a row of five swollen caps on the sub power board that feeds the LED driver board. I decided to replace ALL of the electrolytic caps on both the power boards, somewhere around 22 of them if I remember right. I also replaced the 1000uf 35V cap on the main board. I selected all Panasonic and Nichicon with better or equal specs on ESR and ripple current. I also replaced anything where the board looked a little brown from heat. So I replaced a handful of resistors with higher wattage versions, a couple of diodes, and a VIPER22ADIP-E low power offline switcher.

After replacing those, the TV behaved exactly the same way as before. No improvement. Once I got to looking more closely at the main board, I noticed a little surface mount component that was burnt and melted into a little ball, with a blacked area around it. It was next to one a cable header that connect to the DMD board. On the bottom of the board, on the row of pins for that header, I noticed two of the pins were bridged together with lots of solder. That explains the burnt component as this was a dead short of a 5V line. But the solder had to have been like that for the life of the TV and so probably had nothing to do with the power-on problems. This short prevented 5V from reaching the DMD board on one of the pins. I fixed it and replaced the burnt SMD ferrite bead and all the components near it, including a few little SMD capacitors, some resistors, and a zener diode. As I expected, that didn't fix the original problem. But I noticed that once warmed up, when I access the service menu, I have options that were missing or inaccessible before.

In my inexperience, I at first assumed that all those small cylindrical capacitors on the main, DMD, and LED driver boards were the solid polymer type. After more research, I realized that they might well be aluminum electrolytics. Since this thing improves when warm and since aluminum electrolytic capacitors have lower ESR when warm, I still think the problem might be related to capacitors. So I got an ESR meter and started testing those caps. I soon realized that testing them in-circuit is almost useless, as most of them are in parallel with other caps which lowers ESR reading dramatically. I desoldered a few to sample them and found some that had high ESR readings.

I am thinking of replacing all of the V-chip/SMD aluminum electrolytics that remain in this thing, about 140 of them, leaving the handful of green inked ones that are obviously polymers. It doesn't make too much sense to desolder all of them for testing, as it is hard to get these V-chip packages off without damaging them. To save some money, I was thinking of putting in Wurth capacitors in a regular radial leaded package and just bending the legs to fit the pads. Those are considerably cheaper than something like Panasonics in an SMD package.

What do you guys think? Should I do this, or should I just junk the TV? I am not sure what else to try here. I don't have an oscilloscope to see how clean the power is coming from the power boards, but I have voltages where they should be everywhere and all new caps on power supply. Actually, there are two pins on a cable connecting the power board to the main board that should have 16V according to service manual where I read 18V. Should I worry about that? I am not even sure my meter is accurate. It is a $30 Bosch automotive DMM. The thing is, this slightly high voltage is present when the thing is working great after warming up, so I don't suspect this has much to do with anything. I could be wrong!

Hi, after you replaced the five caps and the other big one on sub led board did you try the TV then?
I always find it a good practice to only do one thing at a time, then see if it fixed it or not.
As far as the other power supply I would not have touched it unless you saw some obviously puffed caps.

I have never seen a power supply on any of these LED DLPs cause ANY problem other than the tv just would not turn on.
I have wished it caused problems with turning off or rebooting but sadly it was the mainboard.
The only power supply problems from puffed caps I have seen were from very puffed caps. They just would not turn on.
I see a lot of them with slightly puffed caps that worked fine but I replace them anyway because I would rather sell it with new ones
rather than questionable looking caps.

I think your problem is in the mainboard and as far as replacing all those little silver caps on it
I would not do it unless you saw one obviously split on top.
I think the caps would cost more than a board and that is too much money to spend on a guess.

I am beginning to wonder if some of these mainboard problems are from that
big chip that has the heat sink on it.
I think as far as mainboard troubles like yours I would want to try to re-flow that big chip first.
I my self have never done that.
If you are interested in trying a different mainboard PM me.

[oysteroid]

Re: Samsung HL67A750 DLP with bad caps!

stanman2242,

Hi, after you replaced the five caps and the other big one on sub led board did you try the TV then?

No. I replaced all of the aluminum electrolytic caps on both power boards before trying it again. And everything behaved just like before. I didn't have an ESR meter at the time. But when I got one, I tested all the caps I pulled from those boards and roughly half of them had quite high ESR readings. One of them, a mid-sized one (don't remember the specs) had an ESR of about 20 ohms but looked just fine, with no bulging. The five bulged ones also had very low capacitance readings. They were supposed to be 2200uf and measured something like 900uf.

I've been thinking of trying the reflow thing. I guess it is worth a try before trashing the TV. But I don't have a heat gun and I am not comfortable putting that toxic board in the oven where I put food! Who knows what kind of crap gasses out when you heat it to 400 degrees! Now I guess I need to buy a heat gun too! Or a reflow oven!

As far as the cost of the caps goes, I have estimated that if I use the Wurth radial lead caps, I can probably replace all 140 of them on the main board, the DMD board, and the LED driver board, for under $35. A bunch of them are only about 13 cents each. I'd have to use V-chip/SMD caps on the DMD board, as the radial packages won't fit under the shroud. The worst thing is all the time and tediousness of removing 140 V-chip caps and soldering 140 small caps onto those boards, especially when you have to bend the all the leads to fit the pads!

And some of those caps are definitely bad. I was able to test a few without removing as they weren't in parallel with others and some had high ESR. A few that I desoldered to test were quite high. One 10uf 16v had an ESR of around 34 ohms and looked just fine physically with no sign of leakage or bulging. I realize small caps have higher ESR, but 34 is too high even for that size. Another randomly sampled identical one had an ESR of just a few ohms. While on the board, the 34 ohm one measured 0.08 ohms because of other devices in circuit with it. Desoldering them all just to test them wouldn't be good. I'd probably damage them in the process of removal and so might as well just replace them all.

The problem has to be something that changes with heat. ESR in caps is one such thing. I suppose bad BGA solder contacts could change with heat flexing the board or something. It is probably either solder problems or bad caps. After all, most of those small SMD caps only have an expected life of 2,000 hours. This TV is over 8 years old and has seen heavy use!

[oysteroid]

Re: Samsung HL67A750 DLP with bad caps!

Well, I finally replaced all the small electrolytic surface mount caps on the mainboard and it works! FINALLY! Now I just need to get it all back together!

[oysteroid]

Re: Samsung HL67A750 DLP with bad caps!

It didn't last more than a day. Back to troubleshooting.

[stanman2242]

Re: Samsung HL67A750 DLP with bad caps!

It didn't last more than a day. Back to troubleshooting.

Oh no, That's a shame after all that work.
I know I would never tackle a job like that but
then again I might have when I was younger, I am 67.
I still have a few of those laying around if you need one.
I just got one with only 7100 hours on it.