: Hitachi & Other Manufacturers Convergence Problems (STK392-110 ICs) Read Post 1
The sad thing is if you replace the ICs and don't replace ALL the bad resistors, as soon as you start up the unit, you wlll blow the ICs and need to start over. It's also possible (as mentioned before in this thread) that there could be some broken solder on the board itself.
You replaced 2 of the resistors, however, there could have been 3-4 bad ones... See the previous posts in this thread with resistor numbers.
The local Radio Shack had tested all the resistors. I did not see broken solder before putting the board in, but I am new to this, so it would be easy for me to miss something. What is the best way to identify broken solder?
One needs to test the circuits with a volt/amp/resistance meter, usually when the board is in the TV, with the TV on, to see if the readings are as indicated in the service manual.
The hard part about testing a board for cracked solder is that sometimes the circuit will be fine because the solder is "touching" while other times it may not be. This is often why items will work when warm and not when cold, due to the thermal expansion.
2006-06-15, 09:17 PM
This sting is great and what I suspected. My 3 year old 43uwx10b has the 110 amps installed, should I order the 120, 150 or 180? I found the spec sheet of the STK392-110 and the "typical" circuit has current feedback resistors as 3.3 ohms, compared to the 1.0 ohms of the installed board (toasted). I replaced the resistors and it still doesn't work (converge) This shows they were pushing the current about three times what the typical design should be. If I change the amplifier what are the value changes necessary? If anyone is interested Sears parts actually stocks the board ($236), and I ordered the service manual ($39) which I hope will point out some details. On the sears site there is a basic exploded view of the major parts. Thanks for the pointers guys. ( I worked on Advent projection TVs for 6 years back in the mid 70's) So I've repaired my share of TVs.
2006-06-24, 11:26 AM
My question is how difficult is it to take out the entire PCB, and bring it to an authorized Hitachi dealer, and have them replace the new resistors & amps.
2006-06-24, 11:30 AM
This thread has lots of terrific info, and many of the home repair work examples have been done by people who know their way around the innards of a TV set. For others thinking of doing a board swapout, I don't recommend doing it unless you have an electronics repair background. You could cause further problems to the TV and/or void your warranty. TVs also have high potential for causing electrical shocks.
Having said all that, if you still want to go ahead with a board swapout or repair, bear in mind that PCBs and ICs are sensitive to electrostatic discharge, so make sure you follow all the necessary electrostatic discharge precautions to protect the chipsets and circuitry:
find or download a proper service manual for the TV set so that you can prepare
remove metal objects from your hands
stay grounded as you touch PCB boards (grounded wrist-straps are available from electronics and computer supply stores)
handle boards by the board material and not by the chips or electronic components
stay grounded as you remove them (yes I repeated myself but its so da#ned important!)
immediately put the board into a properly shielded chip bag (available from electronics and computer supply stores) and fold it over to seal it with tape
keep the board out of direct sunlight and away from any sort of magnetism or static electricity sources as you transport it
My question is how difficult is it to take out the entire PCB, and bring it to an authorized Hitachi dealer, and have them replace the new resistors & amps.Hitachi will probably simply swap the board. I believe they charge about $3-400 for this. Shoot them an e-mail or give them a call.
Although Stampeder's suggestions are all correct, very few people use all the "grounding and bag" precautions with TV boards. I believe they may be more "robust" than computer boards, nevertheless, one cannot be too careful.
2006-06-24, 12:03 PM
...one cannot be too careful.And I am the first to admit that I have not always been so careful. I blew up my first home radio when I was about 12... ;) so imagine the heartbreak of frying a TV set board! :eek:
2006-06-24, 02:23 PM
Thank you Stampeder & 57 for the advice.
2006-06-28, 11:29 AM
FYI The "manual" from Sears Parts ( $39.99 plus $10.99 S&H) is a cheap copied CD with the PDF files. The shipping and handling is a plain non-ridgid envelope. Not impressive at all. The prints are hard to read even on "B" (11 x17) paper.
2006-07-18, 03:14 PM
This is the sad tale of a Hitachi 53UWX10BA.
At less than three years old (Oct 2004) both STK392-110 chips were professionally replaced.
This lasted until May 2005. The same chips were replaced by another shop. This shop failed to completely fix the issue as there was a slight convergence issue in the upper left part of the screen that wasn't real noticable. But since the shop was going out of business and I had to pick my TV up myself on the second to last day they were open I couldn't hardly complain.
Sept 2005 the convergence issue popped back up. A third professional repair party came and and replaced the STK392-100 chips and the "coil" (which I haven't seen mentioned in the forums.) By the way, this 3rd "pro" didn't know what he was doing with the convergence processes via the remote and he got frustrated and left because he kept losing his settings and then didn't take the time to align the screen. He grabbed his tools and ran out of the house when I pointed out convergence flaws. I found the convergence instructions online and finished the job myself and the picture looked great...for a while...
Well now in July 2006 the TV is out of convergence again!!!!
I have asked each time if there is some thing wrong with the TV to cause this and each repair person has said no. Has any one else seen these chips go out as fast as 7 to 9 months?
I've ordered a two STK392-110 and will be attempting to fix this with the help of a neighbor who has electronics expirience. I'm beginning to think if we can replace the chips ourselves and I can get a pair for under $20 I may have to start replacing them proactively every 6 months or so.
Any thoughts? Any tips of what not to touch inside?
2006-07-19, 02:25 PM
I have been reading the different posts regarding the convergence issues with older models (UWX, FDX, SDX). Have there been similar issues with the S Series, like my 51S500 for instance? This was the next generation, but are they different enough, or are they using the same boards in the same configuration? I believe the line is at least 2-1/2 years old.
2006-08-05, 08:50 AM
I have a few questions regarding my convergence problem on my Hitachi 57SWX20B, made in 2002.
1) Should I replace both the existing Sanyo STK392-110 with STK392-150, (output ICs) and use a silicone heat sink compound when installing. If I use STK392-150 do I need to change any resistors? Which ones, what value, wattage rating?
2) I have read that I should check and if necessary replace resistors RK50, RK54 and RK58. Please correct me if I am wrong, but I believe they are 1 watt, metal oxide resistors.
RK50 = 2.7 ohm
RK54 = 1.2 ohm
RK58 = 4.7 ohm
3) Where can I buy replacement STK392-150’s in CANADA. It appears that they are readily available in the US for about $15US, i.e. www.mcmelectronics.com . I have also read that I should be careful about counterfeit knock-offs from China, selling for about $6US on Ebay, which are highly inferior, where the pins fall off in your hands. I have found that Globe Electronics - www.globalsemi.com are the authorized distributor for Hitachi in Canada, when I called Hitachi, I was automatically connected to Global. The price here is about $32, (no picture). The STC392-110 here are priced at about $66. When I called, the person there could not confirm that they were original Sanyo ICs, and said that they were “generic” and could be made by anyone. I think that this was their generic statement and did not know off hand if they were genuine Sanyo parts. As I understand it “STK” is a Sanyo chip identifier. Please let me know where you bought your ICs in CANADA and your experience good or bad. Please provide the website or phone number. If you bought them from the US, what was your total price including tariffs, taxes, etc.
4) I am concerned with electrical hazards within the RPT. I believe that in order to remove the ICs, I will need to have access to the underside of the circuit board to de-solder the output ICs. However there are several connections (about 16) that would have to be removed. the flyback transformer is located on this board, one red lead, three black leads, on the top with rubberized caps which may retain a high voltage charge. How do I safely disconnect these leads? Is there an electrical hazard here?
There is a warning sticker inside that says:
HIGH VOLTAGE WARNING
DISCHARGE THE RESIDUAL ANODE – VOLTAGE CHARGES TO CHASSIS ONLY
WHEN SERVICEMAN DISCONNECTS ANODE LEAD AT FLYBACK TRANSFORMER
I have read that if I leave the TV unpluged for four hours, the charge will be discharged to a safe value.
5) Once the new output ICs are installed, do I have to make any adjustments or calibrations, or do I just need to perform the Magic Focus? Before I knew that I was dealing with a convergence problem I tried using Magic Focus about 3-4 times, and the TV responded with the error code number 5. I have read that I should not try using Magic Focus until the set is repaired. I am lead to believe that further adjustments may now be required in the DCU.
Thanks in advance for your help...
4. 4 hours should be plenty of time.
5. You should do the DCAM manual convergence, not just the magic focus. See the Sticky at the top of the Hitachi forum on the DCAM.
I cannot answer your other questions for certain.
1. If you change the IC model number, I believe the resistor values are then different.
2. I would check all the resistors on the convergence board. I believe there are more than 3.
(I had my TV repaired by a pro as indicated earlier in this thread, but lots of people have done it by themselves)
2006-08-07, 05:58 PM
My Hitachi 43FXW20B
seems to have the same typical problems..
if you press on..it sounds like it wants to turn on..(tick tick tick) and then back off. I was told it was the convergence circuit...
does anyone know where I can get the parts to fix this? or if anyone on here feels like meeting up and sharing some talent?
If its replacing IC's and resistors..I'm sure I can pull that off.. I'm a 4th yr electrician, learned about electronics in college...
Thanks in advance!
The TV not turning on and the ticking may be a blown relay, or power supply, which may not be related to convergence at all.
2006-08-08, 04:40 PM
any idea what I should check on for the power supply? or where I might check for the relay? the noise it made wasnt very loud, it sounded like it wanted to turn on but just couldnt...
can I test resistors while they're on the board?
I checked them with my ohm meter and compared them to my book from school and they seemed off.
2006-08-08, 08:19 PM
TV makes a couple small noises when you try to turn it on..red light comes on..(briefly) then goes off.
I checked a few more things out on the board tonight.
I checked the 2 resistors on the right side of the power supply board
R924 & R925.. and I believe i got around 3900 ohms, according to my book, it states 3920 +/- 5% (orange,white,red,gold).
I checked the ones near the STK392-110's, they're a little more whack from what I gather.
RH11,RH12,RH15 (Brown,Grey,Gold,Gold), I believe they were all around .8 ohm to 1 ohm.
RK50 (Red,Red,Brown,Gold) .8ohm
RK51 (Orange,Brown,Gold,Gold) 3.6ohm
RK54 (Brown,Grey,Gold,Gold) 2.1ohm
RK55 (Brown,Green,Brown,Gold) .6ohm
RK58 (Yellow,Brown,Gold,Gold) 4.9ohm
RK59 (Couldnt make out the colours...) .8ohm
So I figure a couple of them passed, given the expertise on this forum, is it likely that it is just a few resistors, or maybe the STK392-110 as well?
I'm wondering, how on earth does one even go about replacing an STK392-110, I practiced my soldering skills on some old 486 motherboards by trying to remove components, and I did not even have the slightest bit of luck. I used Coldheat which could be why. I've got a Weller soldering gun, but it seemed a bit too large for this application, and I figured a 486 board would be pretty close.
Thanks in advance!
2006-08-13, 10:35 AM
After several years, I had the red convergence problem. I replaced the STK392-110 ICs and prior to putting the board back in found that RK42 was bad (open). I decided to replace this resistor. The service manual purchased from
www.servicemanuals.net shows this as "METAL FILM RESISTOR(2.2OHM 1W )" however it looks nothing like RK50 which is the same part number. RK50 has the correct color codes to be a 2.2OHM resistor. However, RK42 has a different color code. RK42 looks to be: Brown Yellow Brown Gold, which would be 140 ohm 5%. RK42 also has a white painted middle that I don't think is part of the color codes. I can't measure RK42 as it is open. So, does anyone have a service manual that shows RK42 as other them 2.2 Ohm. Anyone ever need to replace RK42? If anyone gets a chance, can they please measure RK42 and let me know what they see. Anyone have any advise from here?
2006-08-15, 10:24 PM
Concur... I don't want to fix this thing AGAIN. Where can we buy a new/refurb one from?
Also, do you guys know how much (or if it's even an option) to replace the entire DP1X Convergence PWB? Do you know where one could get their hands on one of those?