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JVC RX-999V Display/Amp Issues

I just registered in part of this thread and lurking this website in general for a bit of time. Thank you in general to those helpful people out there.

This old thread gets a bump and I don't feel my specific situation is relevant to start a new thread.

The old hifi thing is somewhat new to me and I have aquired most of my stuff via dumpster diving. Though after clicking around here and there in forums and Youtube I unfortunately fell in lust with the JVC RX-1001V. I mean 89 buttons with most of which I will never need or use? Sign me up. Watched a few auctions on eBay and local platfroms come and go for prices I was unwilling to pay, until some guy an hour drive away listed one for sale but misspelled the title so I got it faily cheap and in proper working order (as far as I know).

Yesterday I pulled the top case to reveal maybe a decade or so of dust covering everything. But, someone had been in there at one point or another but I canot tell for what. The tie wraps holding the looms together are original and none of the screws show signs of being touched with a screw driver. Maybe to do a dust cleaning too. All parts look original, even the fuses.

Being bored, I used my Flir thermal imaging camera and had a look around. There is quite the thermal gradiant in that case and componentry; a 50C spread. Maybe it is relevant to the display issue, but on the main amplifer board around ENH-071 behind the right side display are several small components that reach upwards of 90 degrees Celcius (Flir 21). That heat is soaking the board which powers and controls the right side LCD display (Flir 24 - lower part of picture). As shown in the pictures, the right LCD panel is notably hotter than the left panel (Flir 18, 19, 20 (20 - with top case off).

All was good until I carefully cleaned out the dust and reinstalled the protective cover, now my right side display is doing a flicker dance. Sometimes the display reads "PHONO" sometimes "HONO". Good times.

For your curiousity and as a thank you, here are a few thermal image / visible spectrum hybrid pictures showing the RX-1001 at initial power up and after being on with speaker volume set at 5.5 for about an hour. Yes...I need to do something about my cabinet as it is way too small of an enclosure, but I digress, I have little overall space to work with. I may just throw in some computer housing fans to drive down the temps and do the LCD light modification. As you can see in the photos once the unit has been powered on for some time, the LCD display is registering into the mid to upper 30C temps.
 

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I am not really sure if the temps of those small components are normal. Did some dumpster diving at the recycling a few days ago and pulled out some USB powered slim line fans and installed those into the receiver then plugged into the switchable power supply. From the same angle and the thermal camera at the same spot for metering, the temps behind the LCD have dropped 3 to 4 C. I imagine if the receiver vented to open air, the temps will drop another 1 to 3 C.

1st picture is original temps, 2nd pic is with two 45 mm slimline fans running constant, pulling air through the unit and exhausting out of the top. Both photos are after about an hour of usage of the receiver. SEA, D. AP and Dolby all turned off.
 

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Just registered and am a complete newbie, but I happen to have a RX-999v with display lights that have not worked for the past 20 years and a Google search landed me here. I bought it new at Circuit City (yeah...) in 1990 or so. Everything has always worked, but the display lights went out in the mid-90s and I had a local guy repair it. The lights failed a few years later and the shop was out of business by then, so I just dealt with it. I live north of Dallas and there is no one near me who works on older amps like this, so I thought I would open it up and see if I could find any obviously burned out components. I pulled down the schematic and disassembly instructions, but am stuck at present. I have removed the top cover and front panel, along with the 4 plastic rivets across the top circuit board, but the board remains attached to the front panel by these pin assemblies the top left and right corners (see photos). How does one detach these two boards from one another? The attached disassembly instructions do not show these pin assemblies (sure that phrase is incorrect, but I am a novice) so I am flummoxed as to how to separate these boards. Thanks in advance...
 

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A bit of digging tells me these are right angle header connectors that connect the top green PCB to the front panel PCB. I tried wiggling them apart but to no avail (very gently as I didn't want to break anything) but I cannot tell if they are friction fitted (and so can be pulled apart) or latched. Any advice appreciated.
 
A few of the plastic rivets that secured the circuit boards to the frame have cracked from age. Is there a part number or replacement source for these? Is it a standard size? Thanks...
 
If it's the kind that has a pin that spreads the rivit, Mouser and DigiKey sell them. You would have to measure the hole or what's left of the rivit and look at the datasheet for the correct part number.
 
Thanks so much. Was able to get the boards off the unit, and low and behold, it is the exact same issue Elzikio had. D410, 411, and 412 are all fried; two of the four bulbs were clearly burnt out, and the other two look like they have broken filaments as well, but it's hard to tell. Will replace all the bulbs and the diodes as well (following the JVC Service Bulletin will use diode p/n RD8.2FB3 and use a spacer p/n E48269-001 to keep the diodes 1/4 inch off the PCB).

I have never purchased diodes or spacers or bulb like this before -- is there a vendor you can point me to? I cant find any markings on the bulbs, so if you have a p/n to share, I would be very grateful. (I put both the above part numbers into the Mouser search bar and neither returned anything.

This link from Ersa appears to the the correct diode, but I have no idea if the only do large industrial orders.

Thanks for your patience -- reading this discussion thread has been invaluable. I never would have attempted any of this without learning from all of you, so thanks for taking the time to document what you did.
 

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Forgive a newbie question, but the digikey link you sent is for p/n 1N4738, and the diode JVC listed in the service bulletin is RD8.2FB3. Are they interchangeable?
Just ordered the bulbs from Affinity for Artifacts.

​

 
Actually, my worry is that since the 1N4738 has a lead diameter of 0.86 and the RD8.2FB3 has a lead diameter of 0.45 (which the lead diameter of the currently burned out diode) will it fit the through hole on the JVC board? (I haven't removed the old diodes, so I can't tell the hole diameter. )
 
Those are the exact parts I used to update my RX-950V. The diode is an exact sub for the one in the service bulletin. The leads might be thicker because it is a 1 Watt diode as opposed to .5 Watts. The leads fit fine.
 
I was looking at the service bulletin, and it states that "When any of the lamps burn out, diodes D410, D411, and D412 may short."

I read this to mean that the lamps burning out causes the diodes to short. But is there any particular reason why the lamps might burn out? (My worry is that I am addressing a symptom rather than the actual cause of the symptom, i.e., what is causing the lamps to burn out?)

I haven't found any documentation about lamps failing in this model, and my unfamiliarity with stereos like this may be showing. Is it unsurprising for the lamps to burn out under normal usage? Is the only surprising thing (given the existence of a service bulletin) that when this happens in this particular model, it shorts out the diodes?
 
They are incandescent bulbs that only last so many hours or heat cycles before the filament opens. Most last longer than a person would normally keep these units. Let's face it none of these manufactures thought we would be talking about these bulbs 35- 40 years later!! The original diodes were undersized to handle the current when a bulb goes open. It's really a silly design to be honest. Why not just provide a transformer tap that can handle the bulbs in parallel? The diodes should not have any effect on the circuit until a bulb burns out. With the bulb out of the circuit, the diode drops 8.2V and the rest of the bulbs still light. The RX-950V and it's siblings have (3) 200mA bulbs in series. That's 600mA total. When a bulb burns out, there is 600mA of current going through a device rated at 500mA. Not a good idea. I think your model has (4) bulbs, so 800mA! Maybe I misunderstand the circuit, but that's the way I see it.
 
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