Two Home Theater Receivers - Same make & model - blow center

WHAT THE ?


This is JVC's RX-515V Pro Logic Surround Receiver, 80W
mains, 20W Center, 20W Surrounds. 1994 model I believe.


The first one, I bought in 1995 new, blew center channel
last summer. I plugged the center speaker into a mains
output to check it - got sound. Pressed Test, got noise
in all speakers exc center.


I was lucky to EBay a replacement from Texas, and it served
me well until just today. All other speakers, features work.
Just no center.


I do not know if the problem is on the internal input side
of the surround, or the output side. I would appreciate
some help fixing this as I really like the features and extra
inputs these older units have compared to today's.


Why does the same thing keep quitting on this model?

 

[N_Cook]

On 14/07/2015 13:20, thekmanrocks@gmail.com wrote:

WHAT THE ?


This is JVC's RX-515V Pro Logic Surround Receiver, 80W
mains, 20W Center, 20W Surrounds. 1994 model I believe.


The first one, I bought in 1995 new, blew center channel
last summer. I plugged the center speaker into a mains
output to check it - got sound. Pressed Test, got noise
in all speakers exc center.


I was lucky to EBay a replacement from Texas, and it served
me well until just today. All other speakers, features work.
Just no center.


I do not know if the problem is on the internal input side
of the surround, or the output side. I would appreciate
some help fixing this as I really like the features and extra
inputs these older units have compared to today's.


Why does the same thing keep quitting on this model?

Same central speaker with some intermittent short on the VC ?

 

NCook mibht be right about the speaker, OR maybe it is four ohms ? Newer stuff (you call that vintage but I don't) really don't like pfour ohm speakers.

Could also just be a weak point in the design.


Closest print I could get was for a 518 which may or may not be the same. It shos discrete component output stages but the scan is so shitty I can't tell much else about it. But at least it doesn't use ICs that you might not be able to get. Just got through with onr like that I had to slightly redesign for a guy in Pittsburg. Damn shame all the money he has into that unit but he figured it was worth it. Redesigning is not cheap.

But IF it is discrete component it is just a matter of a few transistors, maybe resistors. While I don't call that model vintage, it is probably worth fixing.

Or you could just take some eight ohm resistors from right and left and feed the center from them. That is almost what the amp does in most normal modes, but it does it at line level. Phantom and some other modes don't, but I don't know about you, I think L+R should be sent to the center channel. That way you might be abl to understand the dialogue in a movie amidst all the %^#$$# special effects. It would work for now whilst you get one of them fixed.

 

Nope. All speakers are 8ohm.
Receiver calls for 8~16ohm loads,
that's what I give it.

Additionally, all my inputs are padded
6 & 12dB via Harrison Labs
attenuators. So both on the input
and output sides both of my RX-
515Vs have been very pampered.

 

In that case, see if you can find the layout of the thing to get near where you need to be and inspect the PC board fro bad connectuions. The wway the heat flowsa in these things can do nasty things to solder joints.

And the fact that it is not goiung into protection means it may well be just bad connections. When things short out, it usually won't kick the relay in or maybe blows fuses. I rarely say this - but it might be something simple.

 

jurb:

Thanks for the vote of confidence. I really don't
know my way around inside a receiver. Lots of
tiny electronic components on a PC board. I can
get near the white thing on the back-side of the
center channel speaker terminals, but to solder
I'd need to remove two or three vertical standing
PC boards to get at the mother board, so to
speak.

Rather just do the EBay thing again, and hope I
get lucky.

 

Update: Center channel worked briefly this
morning, then a half hour later it was out again.

Definitely a loose circuit somewhere inside.

 

[Chuck]

On Tue, 14 Jul 2015 05:20:37 -0700 (PDT), thekmanrocks@gmail.com
wrote:

WHAT THE ?


This is JVC's RX-515V Pro Logic Surround Receiver, 80W
mains, 20W Center, 20W Surrounds. 1994 model I believe.


The first one, I bought in 1995 new, blew center channel
last summer. I plugged the center speaker into a mains
output to check it - got sound. Pressed Test, got noise
in all speakers exc center.


I was lucky to EBay a replacement from Texas, and it served
me well until just today. All other speakers, features work.
Just no center.


I do not know if the problem is on the internal input side
of the surround, or the output side. I would appreciate
some help fixing this as I really like the features and extra
inputs these older units have compared to today's.


Why does the same thing keep quitting on this model?

See if you can see any small black plastic rectangles on the amp or
speaker terminal board (relays). Tap on them with a plastic or wood
stick. If the center channel comes back, replace the relay or
resolder the connections to it if they look bad.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

Alright, Mark Z, et al:


I've discovered that I can get center channel - for a while -
by moving the speaker wire around in the center ch
connector on the receiver. Last night I stripped off an
extra long length of wire, so as to bend it over to double
the thickness.


That worked - last night. This morning I turned it back on,
and got center for about ten minutes before it cut out again.
I fiddled with it some more, and discovered that by having the
speaker wire(16AWG by the way) *barely in* the connecting
terminal, with the locking tab left up, I get center pretty
consistently. If I pushed the positive in all the way - NO
center. If I jiggled it - intermittent center. So we'll
see how long it produces center with the positive barely hanging
in there. Different times of day, the center works, other times,
not.


My original RX-515, which is still in my cellar, is definitely blown
center, at the component level. No amount of jiggling or
doubling over the copper strands is gonna pass sound through
the center speaker with that thing.


And the sad part of all this is JVC is OUT of the home audio
business! Here they had a great mid-price surround-sound
receiver for mid-1990s, ample power, connections for TWO
tape loops(great because I have an EQ on one and my
tape deck on another), and a phono input.


I couldn't give two shits about HDMI inputs, bluetooth, and X.1
digital surround if I can't hook all of my analog gear up to it!!


So I'm going to buy every remaining RX-515V out
there, at least just for parts interchangeability.

 

[Mark Zacharias]

"Chuck" <chuck@mydeja.net> wrote in message
news:k3ncqatvmhho8db2sos0rd2ditd6qf0l7t@4ax.com...

On Tue, 14 Jul 2015 05:20:37 -0700 (PDT), thekmanrocks@gmail.com
wrote:

WHAT THE ?


This is JVC's RX-515V Pro Logic Surround Receiver, 80W
mains, 20W Center, 20W Surrounds. 1994 model I believe.


The first one, I bought in 1995 new, blew center channel
last summer. I plugged the center speaker into a mains
output to check it - got sound. Pressed Test, got noise
in all speakers exc center.


I was lucky to EBay a replacement from Texas, and it served
me well until just today. All other speakers, features work.
Just no center.


I do not know if the problem is on the internal input side
of the surround, or the output side. I would appreciate
some help fixing this as I really like the features and extra
inputs these older units have compared to today's.


Why does the same thing keep quitting on this model?


See if you can see any small black plastic rectangles on the amp or
speaker terminal board (relays). Tap on them with a plastic or wood
stick. If the center channel comes back, replace the relay or
resolder the connections to it if they look bad.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

I've worked on analog receivers almost every day for 33 years. While I
cannot diagnose via usenet, if there IS a history of these blowing the
center channel, I would look very closely at solder connections relating to
the bias transistor. This is the type of thing that might cause such a
history on a given model type.

The advice given on the relay is good if the channel volume is merely down
or especially if the volume is intermittent and comes back with an increase
of the volume control setting or as he said with tapping the relay body.

Mark Z.

 

Depressing discovery:


These particular JVC receivers have PC boards
arranged in a specific way: main "mother" board at
the bottom, with two input boards angled 90deg. to
it - vertical.


On the larger of the two vertical PC boards are most
of the inputs: Tape 1, VCR in/out, CD, Video, & Phono.
This larger vertical board interfaces the main board via
two multi-pin connections(20-30?) pins each.


It is when gently moving this board side to side or up/
down, that I can cause the center channel to cut out in
surround mode. In regular stereo mode, moving that
input board has no effect aside from minor crackling.


This model receiver is just over 20 years old, and my
examples of it are showing its age. Unfortunate, as
I have no need for the features of modern receivers if
ya cain't even hook up a phono or a cassette deck to
'em!



What I might end up doing is using the old JVC for all my
analog sources, then Tape1 out to the "PC" or DVD input
on a new digital 7.1 receiver. My TV and DVD player can
just HDMI out to that modern unit, and when I want to
listen to CD, cassette, 8-track, or records, i just select
that input on the old JVC, and the remaining analog audio
input on the modern receiver.

 

Just got my third JVC RX-515V in the mail
today - fully functional, but with same
problem:

The smaller PC board perpendicular to the
mother board connection has eroded over
21 years. Out of the box, no center channel
in pro-logic mode. After some wiggle and
tapping, it worked.


So what I will do is use this RX Receiver as
a stereo only for all my analogs, and feed tape
1 out to a modern digital X.1 surround receiver
with pro-logic for surround from 2-ch sources.

 

Where are you geographically ? Maybe you should just bring the thing over (Ohio) with some money and some beer.

If I fix one here, you'll probably know how to fix the other two, unless you smoked the original one.

But really, in text this is worse than trying to do it over the phone unless you are with some seriously good people with tech and communicationg by whatever means.

I am different than alot of techs, I WILL let you watch.

It's the talking that can costya.