• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Lights replacement on receiver not working as intended ?

T

TrevorBarten

Well-Known Member
I was working on a jvc vr-5505l receiver and it has this selector board with 2 rows of 4 lights on it. Basically all the original ones had disintegrated so I bought some modern day led light replacement not thinking much of it. However when I put those on they all lit up at once and the selection knobs only caused the correct ones to light up more but it didn't cause the others to turn off. Is this because they are more efficient ? Any tips on how to proceed ? I checked the service manual but cou;dn't seem to find what lights where used on this part.
 
Register to hide this ad
Someone smarter than me will hopefully offer some advice.
Seems to me "sometimes" a resistor is needed to equalize the load difference between incandescent and LED lamps.
 
Any lamp(s) drive my an open collector or similar TTL sourcing output will still receive voltage with the TTL device on an "off" state. Incandescent lamps have relatively low resistance until the lamp filament increases in temperature, so that is generally sufficient to pass any current leaking the TTL switching device without illuminating. An LED uses such a comparatively lower current that is can illuminate on just a very few milliamps of leakage current.

@goodolpg is correct that a load resistor could be used to pass that leakage current, but it must be sized properly to prevent causing excessive current when the lamp is supposed to be on.
 
Is the supply voltage to the indicator lights AC or DC. It is also important to know the voltage being supplied. It sounds like your original lamps may have been powered by A/C voltage directly off the power supply board through the selector switch. Until we know these parameters it is difficult to know what configuration of the LEDs will work in this application.
 
Watthour said:
Any lamp(s) drive my an open collector or similar TTL sourcing output will still receive voltage with the TTL device on an "off" state. Incandescent lamps have relatively low resistance until the lamp filament increases in temperature, so that is generally sufficient to pass any current leaking the TTL switching device without illuminating. An LED uses such a comparatively lower current that is can illuminate on just a very few milliamps of leakage current.

@goodolpg is correct that a load resistor could be used to pass that leakage current, but it must be sized properly to prevent causing excessive current when the lamp is supposed to be on.
Click to expand...


Thanks for the tip I'll try looking for replacements in that direction.
 
aldena007 said:
Is the supply voltage to the indicator lights AC or DC. It is also important to know the voltage being supplied. It sounds like your original lamps may have been powered by A/C voltage directly off the power supply board through the selector switch. Until we know these parameters it is difficult to know what configuration of the LEDs will work in this application.
Click to expand...

It's ac and I am pretty sure what you are saying is correct. I'll have to take a look and check though. That wont be for a bit though so if we assume that what you said is correct and the voltage supplied is AC, would the incandescent lamps Watthour suggested work?
 
Take a look at the schematic. The schematic for the VR-5505 shows 8v 150ma.

Perhaps the schematic for the L shows the specs, or maybe they are the same?

Rob
 
Dammit - @Robisme beat me to it. They appear to be a miniature screw base (Type E-10) lamp, which could be more difficult to find.

You can get a 5-pack of them from the UK through that auction site, but they are spendy.
 
Last edited:
HOWEVER...

...The schematic shows the transformer secondary voltage for the lamp circuit at 6.8V with 120V primary supply. That makes me think that it might JUST be acceptable to install the more commonly available 6.3V rated lamps and save a tuppence or more. The common options there would be a #40 or #46 indicator lamp. They are about a quarter apiece ($ US).
 
I ended up ordering some 5v 0.4 w and 5v 0.6 w lights before you guys told me the original spec. The company I ordered from didn't label the bags so I don't know which ones I used but these work fine and look exactly the same as the originals that disintegrated so if anyone has a similar problem and can't find the original spec those should work fine.
 
Watthour said:
HOWEVER...

...The schematic shows the transformer secondary voltage for the lamp circuit at 6.8V with 120V primary supply. That makes me think that it might JUST be acceptable to install the more commonly available 6.3V rated lamps and save a tuppence or more. The common options there would be a #40 or #46 indicator lamp. They are about a quarter apiece ($ US).
Click to expand...

I ordered some replacement before you commented. Since I measured 4.6 v when I checked and not 8 volts I went with 5 v lights which seem to work just fine.
 
It's worth noting that LEDs require DC voltage to operate, so if run from an AC supply they will flicker unless a diode is used to correct the circuit. A dropper resistor will also be needed to go down from the 6 - 7 volt feed to the LED friendly 1.5 or so :-)
 
For a "raw" LED that is true. However, there are LED assemblies which include polarity protection, current regulation, and thus accept a much larger range of voltages in both DC and AC.

index.php
 
Markoneswift said:
It's worth noting that LEDs require DC voltage to operate, so if run from an AC supply they will flicker unless a diode is used to correct the circuit. A dropper resistor will also be needed to go down from the 6 - 7 volt feed to the LED friendly 1.5 or so :)
Click to expand...

Are you on 50hz power there? I don't notice a flicker using LEDs with 60hz AC unless I don't look directly at them.

Rob
 
You must log in or register to reply here.
Back
Top Bottom