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Member
b0w_bender
Posts: 3

Re: red light flashing on a 42HL196.

thanks I would prefer to be alive and without a TV then dead :-)

I'll look for a tech. I'm a highly mechanically inclided person but when it comes to electronics i'm an ignoramous so probably best If butten it back up and take it to the recycling place.  We got 6 years out of it and we'll look at a different brand for the next one.

Member
chaosmountain
Posts: 1

Re: red light flashing on a 42HL196.

[ Edited ]

One thing I noticed that no one touched on, is the heat sink ?

 

It is kind of a pain to have to desolder it along with the STRW6765 because that thing is bonded big time to the heat sink by the thermal compound.

I would like to see a photo of what IKnowTech did with his custom heat sink.

 

I bought one of these off of craigs list for $35.00, ordered the STRW6765 off E-bay for $8.00 shipped, spent an hour taking out the board, replacing the part and putting it back in.

 

It fired right up and ran great!!

My 28 year old daughter is a happy camper to say the least!!

It is for her room as she has been watching TV through her PC monitor which is only 17"!!

LOL!!

 

Here is a photo of the part for anyone who wants to know exatly where it is and what it look like.

 

 

 

 

Member
IKnowTech
Posts: 9

Re: red light flashing on a 42HL196.

I still occasionally check this forum even though the TV has been working fine since the repair.

 

As I mentioned, I really don't want to haul the TV down and open it up just to take pictures, but I can briefly describe what I did with the heatsink.  I was stumped at first as I tried to find an extrusion that was about the same profile but longer, so adding a couple small chunks turned out to be the best option.  Since I had the heatsink removed, it was much easier to make modifications before re-installing it.  Here's what I did:

 

The non-finned center flat area on the opposite side of the STRW6765 regulator chip is just over 0.5" wide.   I had on-hand a few small heatsinks for bridge rectifiers; base dimensions 1'' by 1'' with six 1.75" tall fins and a hole in the center of the base.  I carefully sawed one in half so I had two pieces 0.5" by 1" with three fins each.    In each piece, I drilled a #4 size hole about an inch deep in the center of the base, opposite the finned side. On the removed heatsink, I marked two drill spots 1-1/2 inch apart symmetrically centered horizontally on the existing regulator mount hole and centered vertically in the flat area, and drilled two #6 holes (cleaning off any burrs). The two heatsink pieces were then coated with thermal grease on the bases and attached to the non-finned flat area opposite the regulator chip side.  #4 self tapping 1" screws through the chip side holes of the heatsink fasten the two pieces; before tightening them for good, line them up so the fins are in line and centered in the non-finned channel. 

 

The added heatsink extends past the edge of the PCB but they are clear of any obstructions, and the fins run in the vertical plane in parallel with the extrusion of the heatsink.  I estimate that the theta of the heatsink is lowered by probably 2-3C/Watt, which amounts to between 20-30C reduction in die temperature if the chip is dissipating between 10-15Watts.  This can make a huge difference in reliability for a device that runs as hot as this one seems to in this design. 

Member
harlock
Posts: 3

Re: red light flashing on a 42HL196.

do you have a record of the cap values for the ones you replaced? it would be nice to order the caps without having to open up the tv.

thanks


IKnowTech wrote:

To verify this theory, I soldered around 50uF of ceramic capacitors on three rails; 24V, 12V, and 20V.  These were soldered on the backside of the power board in parallel with capacitors C872, C873, C888, C889, C890, C895, and C896.  When plugged in, the 12V remained present after the second relay click, and the TV turns on and works normally.  It appears the problem is bad capacitors and I'll be replacing those shortly.  

 

Member
IKnowTech
Posts: 9

Re: red light flashing on a 42HL196.

Yeah, just happened to see this.  I bought 6 pieces of 1200uF 35V (Digikey P12406-ND) for the 1000uF cans, and 2 pieces of 680uF 35V (Digikey 493-6930-ND) for C895 and C896.  I replaced the rest of the electrolytic caps on this board as well (except for that big 450V can which is quite costly) but the 8 main ones I mentioned above are critical as they are subject to the highest ripple current stress. 

 

Keep in mind that all this may still not fix your set;  you have to go through a methodical process of measuring and ruling out potential failures, which you'll absolutely need the service manual for (Freely available on the web). 

 

And, I'll repeat again, perform such service under strict high-voltage safety protocols.  Don't even think of trying this if you've never worked with 400Volts DC before; It is an absolutely unforgiving voltage level.

 

 

Member
spark_d
Posts: 1

Re: red light flashing on a 42HL196.

Exact same problem here - It's nice to see I'm not the only one who spent thousands on a tv with a shelf life of a few years - thank you for standing behind your broke product Toshiba - I won't make the mistake of buying another one ever again and I'll make sure that my friends and family won't either.

Member
harlock
Posts: 3

Re: red light flashing on a 42HL196.

[ Edited ]

awesome, i have a few local stores i can buy from so today i will check the only one that is open on a saturday,

i picked the tv up from someone who was moving knowing it had the problem (they were going to take it to the recycler). it did work the first couple times i had it plugged in then the 3rd time i plugged it in the heard the relays click  3 times. so i'll do the caps and if i need to, the voltage regulator.

thanks

 


IKnowTech wrote:

Yeah, just happened to see this.  I bought 6 pieces of 1200uF 35V (Digikey P12406-ND) for the 1000uF cans, and 2 pieces of 680uF 35V (Digikey 493-6930-ND) for C895 and C896. 

 


 

Member
harlock
Posts: 3

Re: red light flashing on a 42HL196.

 

the 46" regza i bought in jan 2009 still going strong. if you are going to boycott every manufacturer who has had capacitor issues that is going to be a very very long list.


spark_d wrote:

Exact same problem here - It's nice to see I'm not the only one who spent thousands on a tv with a shelf life of a few years - thank you for standing behind your broke product Toshiba - I won't make the mistake of buying another one ever again and I'll make sure that my friends and family won't either.




Member
IKnowTech
Posts: 9

Re: red light flashing on a 42HL196.

You've got that right.  The sad truth is that most set makers (and laptops and mobile devices), especially those who's primary business is not home entertainment electronics, have their TVs built by ODM suppliers whose names are unknown with respect to the brands they build for (think Apple and Foxconn).  The reason the support is so poor is because the brand name company has little control over the part procurement practises of an ODM supplier once that ODM makes it to the brand companies Qualified Vendor List. 

 

I've repaired 6 TVs and 1 monitor and I can say that all but 1had capacitor issues, and there were a couple big name brands in that group (names starting with "S").  Two sets had outright design errors as well as capacitor problems (I count my Regza as one of those since I would never have designed a power device to run so hot).  So far my repaired TV has been workiing fine.  I have had one instance where it's internal computer got "wedged" and it would not respond to button presses, requiring holding the power button on the frame depressed for 5 seconds to invoke hard-reset.