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JVC RX-5V LCD not showing info (just replaced backlight Fuse Lamp)

S

SteveKran

New Member
Hey guys...I'm new here

I'm trying to get a JVC RX-5V working for a friend at church. The original problem was the backlight on the LCD closest to the power switch.

I found one burnt diode (D499) and replaced it with an NTE5016A Zener Diode. I also replaced all 3 Fuse Lamps. They all light up properly.



NOW, the LCD screen isn't showing any information. (I believe it was blank from the start) The screen is now back lit, courtesy of the new fuse lamp, but it isn't showing any information.

I looked at some other RX-5V's on ebay, and apparently this is a common problem.

Any ideas how to get the LCD to show information again?


2ytpcok.jpg


Below is what it should look like

JVC-RX-5V-Stereo-Receiver-60watt-x2-7band-Graphic-_57.jpg
 
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Very common issue for this era of JVC receivers. I have the flagship RX-1001V and the right display board is out. You may be able to remove the faceplate and gently push in on the display board a little to see if the LCD lights up again. The just seem to de-laminate themselves after time and unfortunately, there is little you can do.
 
Electone said:
Very common issue for this era of JVC receivers. I have the flagship RX-1001V and the right display board is out. You may be able to remove the faceplate and gently push in on the display board a little to see if the LCD lights up again. The just seem to de-laminate themselves after time and unfortunately, there is little you can do.
Click to expand...

So you're saying it's not a loose solder joint that can be fixed...it's the actual LCD screen?

Any known sources for getting a new one? I'm up to the task of switching them out...pretty good at soldering
 
I have several of these receivers and have never had the display fail. Most likely a bad ribbon connection or cold solder joint.
 
redk9258 said:
I have several of these receivers and have never had the display fail. Most likely a bad ribbon connection or cold solder joint.
Click to expand...

It's not the ribbon connectors or solder joints. The display board attaches to the main board with a 90 degree tongue-and-groove press fitting. The gold plated contacts on the display board get loose and lose connectivity over time.
 
Electone said:
It's not the ribbon connectors or solder joints. The display board attaches to the main board with a 90 degree tongue-and-groove press fitting. The gold plated contacts on the display board get loose and lose connectivity over time.
Click to expand...
Would some deoxit clean and solve this issue?

If not, what do you think would be the remedy?
 
Electone said:
It's not the ribbon connectors or solder joints. The display board attaches to the main board with a 90 degree tongue-and-groove press fitting. The gold plated contacts on the display board get loose and lose connectivity over time.
Click to expand...
Is this specific to the RX-5V? On the RX-950V, I'm pretty sure the LCD is soldered directly to a PCB. Maybe the RX-5 is constructed differently?
 
redk9258 said:
Can someone post close up pictures?
Click to expand...

red....I think you're correct. The LCD is soldered directly to the PCB. There are a lot of pins underneath it that are soldered.

I can't get pictures tonight.....but I'll try to post some up tomorrow.


Thank you for all the help
 
Dang. Too far from me. I pulled the SEA board from my RX-750V to look at. The LCD is soldered directly to the PCB. The pins go into the LCD panel and do go into what appears to be sort of an edge connector. It is encapsulated in epoxy or something. I do not see gold though. Unless there were some event to crack the encapsulation, I don't see how the connection would degrade. I could be wrong about that though. You know though, on this particular receiver the main display has certain segments that fade as it warms up. I was thinking it might be bad solder connections but haven't pursued it yet. I have a noisy transistor (or something) in the amp section that needs fixed first. I haven't had time to work on it though. If you could translate the on time for this receiver into mileage, I'll bet it would be close to 1,000,000! I don't know if LCDs wear out,but maybe this one has.
 
Sometimes there's just a clamping factor-- if you apply pressure to different parts of the LCD assembly, do parts of the display come back to life?

I have a TRS-80 model 102 (early portable computer) where about 1/20 of the LCD didn't make proper contact and was dead. By carefully tweaking the pressure of the clamps that held the assembly together, I was able to get it readable.
 
IDK. It's kinda out of service for now. I did not try to apply pressure to it. When it is assembled, you cannot touch the LCD. I would have to try it with the PCB out of the receiver or something. It's weird how the segments don't just turn off, they fade away over time.
 
Yea i recently finished working on a JVC RX 999 and when i looked closely at the solder joints to from the lcd to the board i could not believe how many of them were cracked which was causing issues with the display glitching out.

I dont think the ribbon cable will become a problem as long as it is not taken out and put back in place a thousand times and handeled with care. (Rx 999v and rx 1001)
 
I have same problems with my RX-5V at tuner display which fade away. I think is a LCD driver issue, not LCD itself. When is power on receiver shows everything but after 10-20 seconds tuner LCD starts to fade and only few segments are lit. Sometimes no information on display and backlight is working. I measure voltages on all displays, the good ones has same voltages on all pins, on tuner display I have a lot of voltages or none.
Second problem: I can t change all inputs just Phono, Tape and CD. Pushing on AM or FM nothing is happened. I measured voltages on phono/tape/cd push buttons and I have 4.98V and arround 1V on FM and AM when lcd starts to fade an 3,5V with lcd without informations(like in second picture)
That I belive LCD driver is gone. Is a LC5813H-246 one, I found an OEM one on ebay.

20170421_183937_zpsnkxkcjac.jpg

20170422_095336_zpskxivwfoo.jpg


I have searched for bad solder joints but nothing wrong.
20170417_144943_zpsnwaoo6fb.jpg
 
Maybe that PCB needs some solder reflowed? Maybe it was hit with a voltage surge? My display does not dim like that. Here's what mine does...
750v.jpg
 
I replaced the bulbs for backlight using 8v and 250mA fuse model I have in hand. Shall I go for 12V one? Previous owner used LED for displays backlight and I don t like it.
Before
20170316_100930_zpsxvixxaag.jpg

20170316_102824_zps9tqhngkm.jpg

After. 8V bulbs
20170316_103412_zpstndutlam.jpg
 
Last edited:
According to schematic diagram there are RD13EB3 zener diodes (european version) and I have 8,4V on lamp. That means my lamps are good, maybe my picture is not very good made. My problem is I can t change to tuner, only CD/Phono/Tape works. And tuner part is not working. I measure voltages on tuner board and I found 12V missing on J102 connector. I followed it on diagram and I found a burnt resistor in 12V source (R862 - 100ohm), I replaced it and Q852 transistor (2SC1740) now I have all voltages on boards.

20170319_165414_zps4yebidrp.jpg
 
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