Question about JVC Televison & Video
To remove the whole unit to replace chips
I have some good advice for you---done this on this model several times and I will attach a few photos as well..
The convergence board is at front of set---remove 2 screws on back on either side---two more tiny ones on front where control door is and lift and remove entire grill below screen off.
There is a inspection plate dead center behind where the grill was--remove it also.
Behind it is the convergence board. It helps to take rear cover off also.
there are about six plugs to remove---three are identical for the convergence yokes----make sure you mark them so they go back in the exact same place as removed.
There should be another plug going to (seen from front) left to the power supply board and another small plug to the front left.
The last plug is hard wired into the convergence board and goes back and up to another board where it can (from rear of set) be unplugged.
Board is held in place by plastic tabs at front of set into the black plastic frame--lift it carefully up in case is also screwed in(not usual).
You now can lift the board up and out the front of the set.
If you look at the resistors---in front of the chips I would test all the small ones there and look for any that are discolored--if memory serves me they are 1.8 ohm and 1/2 watt----only the 1/2 watt resistors will fail and usually the set will not come on if this is the case---power light constantly blinks will be the issue.
Let me know if you have not replaced the chips ever and I will give you some pointers etc.
Posted on Oct 30, 2012
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Posted on Jan 02, 2017
I had a problem with my TV colors not lining up. One day I turned it on and the green was out of wack. I checked this message board and replaced the STK chips, bad soldering and all led to me just giving up on that and buying a whole new Convergence Board ($185). I just plugged this in and though now my Green lines up okay, my red is out of whack. Is there something I am doing wrong? Can anyone help me? Did i miss a step? Frustrated......Bruce
Posted on Aug 18, 2007
SOURCE: JVC AV-48WP74
havent had time to check these things out but here is some raw research I have done
No. The CRT driver ICs are prone to shorting and cause this symptom (I just had one with those very symptoms and the green CRT driver IC was shorted). Disconnecting the CRT board does not clear the short on the board. Often then is a small burn mark on the CRT board under the affected IC (but not always). The IC should be a TDA6111Q. Be sure to note the proper position
of the IC as it should face with the letters TOWARD the heat sink!!!!
Larry, Check the CRT driver ICs on each of the CRT boards.
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
Hi Guys, I don`t see many JVC`s and don`t have the print for this AV48WP30, went out this morning and as customer claimed on phone when you plug set in and turn on it makes a loud thump thump in both speakers 20-30 times then relay clicks, the thump stops, and blue idiot light on front goes dim/bright, dim/bright, have to unplug set to start this same scenario over again. Never develops HV or audio, Will order the service manual today, but would like to know if anyone has seen this before (should say "heard" this before)
I would disconnect each crt board and hv lead one at a time and try. Have seen several bad tubes on that model. The only other problem I have seen on that set is bad convergence amps, however that doesn't cause shutdown.
From Tech Repair CD:
JVC\AV48WP74\just went click*click*click when turned on Video drive IC (IC1101) on the red CRT module
shorted. It looked like bad solder on the B+ was the cause
Frequently Used Top Five Repair Parts by symptom code
MODEL NUMBER : AV48WP30 - TV
SYMPTOM CODE : DEAD
TOP FIVE PARTS :
Above from JVC Web site, also I have seen shorted video drive IC's on the crt boards short and cause this symptom. Try unplugging the 200 volt source to the crt boards and see it the set powers up and stays on. There is a B+ relay which supplies 130 Volts to the horizontal output circuit. Is this relay energizing? I takes about five seconds after the power is turned on for it to energize. If a short is detected on the 130 volt line the blue power lamp on the front will do what you describe and the relay will pulse on and off. (David)
Non-functional Digital Input
1. Power off the unit
2. Disconnect the digital input if it is connected
3. Remove the rear cover
4. On the digital input module, using a shorting pin (PC type) or a
jumper, short Pin 1 and Pin 2 of the
5. Power on the unit
6. Unplug the unit and remove the shorting pin or the jumper
7. Re-attach the unit’s rear cover
8. Power on the unit, and input the digital source
Posted on Dec 06, 2007
I purchased the two IC's STK392-110's and it fixed my problem. I was told that if one IC is bad, the other will also fail.The chips cost about $6.00 apiece via online shopping and required me to desolder the 19 pin's and carefully remove the chip from the heat sink(dielectric made it stick to heatsink), clean, reapply dielectric, and carefully resolder new component. Total cost was about $15.00. Thanks for the help!
Posted on Dec 15, 2007
SOURCE: stk392-110 chip replacement
stk392-110/150/180 all have same fit, form function except the 150's and 180's are basically upgrades for they're more stable (more heat tolerant than the original 110's); I'd buy the 150/180 myself; you can get the stk392-180 for just under 10 bucks on eletronix.com.
Posted on Apr 20, 2008
If this is not resolved soon, the picture will start to bow from the top and bottom. This is a common rpoblem with CRT based projections sets and is in the convergence circuit. If you can solder, you may be able to resolve this yourself. Be aware that there are potentially dangerous high voltages present inside the set even when unplugged.
The problem can be as simple as poor solder connetions at the convergence ICs or defective ICs. In any case, these ICs are large and black and are marked STKxxx. If you can locate these, try resoldering the pins on the ICs. If that fails to resolve the probelm, replace the ICs.
Please keep us posted.
Posted on Nov 17, 2009
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