SOURCE: JVC AV-48WP30 48 in. Rear Projection
this is the raw research for this that I have found. It seems like the most likely culprit for this is the stk chips on the convergence board (JVC didn't put nearly enough heat sink compound on should be a small layer all the way across they put on a couple dabs) I hear tale you can check this out by disconnecting the convergence board and turning on the set . only go after the convergence board from the front (behind the speaker grill is another panel, the convergence card is right behind there) there is a sneak circuit which will kick in possibly destroying at least the dvi input and mabie more if the set is powered on with the back removed and you didn't put a jumper in the right place or cover over a hole in the back of the dvi module (supposidly to keep people from hacking movies, like there arn't easier ways to do that if you really wanted to). if that doesnt fix it then I have found several other possibilities but I am now a few hundred miles from the tv that I was working on so havent had a chance to try this out:
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
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxx
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.
Perry Bower
Electric Medic
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 :
2SC5552-RL
2SC5904-RL
QQH0113-002
STR-F6629B/F7
STK392-110
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)
Symptom:
Non-functional Digital Input
Solution:
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
SB connector
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
SOURCE: jvc tv model av-56wp74
1024x768
Normal
0
Won’t start
The power supply has an automatic shutdown circuit that
senses a shorted component and excessive current flow.
If you can access the convergence board and remove the plugs one at a time
(red, blue or green) for the convergence output, the TV may start up and show a
picture with the unplugged color misaligned.
This confirms a short in the convergence output. The convergence IC failure can
show up as coloured outlines or power supply shutdown.
If this does not help, then there is some other short circuit in power or
deflection circuits. You need a technician to troubleshoot HV or power
problems.
Replacing the output amplifiers
(located within the Convergence IC's) allows the pictures to line up
correctly, and no more color outlines or power shutdown.
This is the most common fault in all makes of rear projection TVs.
Some models of TV require major disassembly and considerable
shop/manufacturer's support to repair because of their design that causes other
power supply or vertical deflection problems. The poorly designed products
require a "bench" repair that can typically cost from $350 t0 $700.
Some TVs are designed for on-site repair and have more reliable circuit design
that does not usually cause damage to other parts of the TV when convergence
chips fail. The ones that usually allow reliable on-site repair are JVC,
Samsung and Hitachi.
It is normal to have some resistors in the circuit burn up or increase in value
from the heat (from 2.2 ohms to 5 or 10 ohms). These resistors must be replaced
with the right value or the chip may fail again.
This is not a simple repair like changing batteries or a fuse. Reading
through the other posts shows many that try and end up with bigger problems.
Your JVC uses STK 392-110 IC's. Misinformed people replace the IC's with
other "new and improved" IC's, like STK 392-150. These are
devices with different characteristics and require different value resistors in
the circuit. Replacing with the STK
392-150 will cause overheating of the resistors and a damaged IC.
If you are in Calgary, I can help. If not, get someone that has experience
working on your JVC. My website is below with some costs and explanation.
calgaryconvergencerepair.weebly.com/convergence-explanation.html
Good Luck,
Easyab
SOURCE: jvc tv
when both the blue light and red light are blinking it means 1 of 3 things. 1. lamp replacement. This often works everytime for the repair. TIP!!! DO NOT USE ANY OTHER LAMPS OTHER THAN JVC AUTHENTIC LAMPS. ANY OTHERS AND YOU RISK DAMAGING YOUR TV FURTHER. 2. the fans are not working properly or need to be replaced. They need to be cleaned every so often and they will stop working from burn-out if not done so. This repair will cost you less than 100 dollars. 3. The ballasts are defective and need to be replaced. The ballasts themselves run about 150 dollars. I tell you I have fixed this TV more times than I care to count, not to mention the number of lamps I have gone through. The guy at the TV repair place now knows me by name when i come to buy lamps. :(
SOURCE: I have a JVC HD52z575 that when I turn it on the
Power supply would be the issue the fix would be my good friends @ www.teexp.com I hope this helps.
Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620
SOURCE: I have a JVC AV-56Wp74 Blue power light on the
There are a couple of common problems this model has--one is easy to confirm.
How handy are you if I tell you to disconnect the convergence board to see if it is your problem?
The blinking blue light means the set is in protective shutdown, and I know a fairly easy way to see if it is your problem and how to fix the set if it is.
Let me know if you need help--I am here to help people and l know a lot about this set.
SD TECH
Testimonial: "this was very helpful thanks"
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