Yamaha CR 620 with loud hum.....

[Skywatcher]

Not if its popping.. Lamps are mis-wired. Could also be the source for your hum..

If I remember correctly, these are wired in "series-parallel".

 

[Skywatcher]

Not if its popping.. Lamps are mis-wired. Could also be the source for your hum..

Look at the lamp wiring photo. I see 5 shrink tubes, and 2 red wires going into one shrink tube.

 

[avionic]

Look at pins L1,L2 , L3 and L4

L1 should have 3 wires attached
L2 has 2 wires
L3 has 2 wires
L4 has 3 wires attached..

The L (lamp) pins are close to the black cap in this photo.

 

[avionic]

The lamps look to bright in your photo. So they are likely the wrong size ..Voltage or current or both..

 

[Skywatcher]

Look at pins L1,L2 , L3 and L4

L1 should have 3 wires attached
L2 has 2 wires
L3 has 2 wires
L4 has 3 wires attached..

The L (lamp) pins are close to the black cap in this photo.

And you'll notice one pin is a "loner" and has no trace connected to it. It serves as a "junction" pin for 2 wires.

 

[avionic]

you'll notice one pin is a "loner"

2 pins L2 and L3

 

[red71rum]

That was a 30 second exposure and iso 64, they look brighter than they are actually in real life. Here is another pic from the day before, a quick snap with my cell phone -

 

[Skywatcher]

That was a 30 second exposure and iso 64, they look brighter they are actually in real life. Here is another pic from the day before, a quick snap with my cell phone -

View attachment 2147733

Could be the camera, but it appears the green condoms aren't on the bulbs.

 

[avionic]

Look at pins L1,L2 , L3 and L4

L1 should have 3 wires attached
L2 has 2 wires
L3 has 2 wires
L4 has 3 wires attached..

If there not wired like this .. the unit will " pop" ...

 

[ConradH]

You've even got the rare plastic headphone hole plug! The bulbs may be messed up, don't know, but that unit is known for having lots of failing caps. IMO, it's a sweet sounding receiver if given a proper restoration.

 

[Drumaniac]

That was a 30 second exposure and iso 64, they look brighter than they are actually in real life. Here is another pic from the day before, a quick snap with my cell phone -

View attachment 2147733

Mine looks exactly like this

 

[red71rum]

Could be the camera, but it appears the green condoms aren't on the bulbs.

I will have to ask the tech during a break in help desk calls.

 

[Skywatcher]

I will have to ask the tech during a break in help desk calls.

Could be the replacement bulbs are too big for them too. It's not a big deal either way. I am just used to seeing the greenish tone.

 

[Drumaniac]

Could be the replacement bulbs are too big for them too. It's not a big deal either way. I am just used to seeing the greenish tone.

I have the same unit and there is no greenish tone. Some are as his picture shows and some are green. The original lamps are not as strong as my pioneers with similar lamp colour.

 

[red71rum]

Could be the replacement bulbs are too big for them too. It's not a big deal either way. I am just used to seeing the greenish tone.

I have the same unit and there is no greenish tone. Some are as his picture shows and some are green. The original lamps are not as strong as my pioneers with similar lamp colour.

I was told the greenish tone is a "sock" that goes over the lamps, again maybe I misheard what I was told: )

 

[Drumaniac]

They come both ways, green or as his picture.

 

[avionic]

They come both ways, green or as his picture.

Not... They were all greenish.. Your green condom has dry rotted away.

 

[Drumaniac]

Not... They were all greenish.. Your green condom has dry rotted away.

You may be correct, mine are a yellowish white and several i have seen are like this. Maybe the green casing has rotted. Cannot remember if they were green 50 years ago lol

 

[avionic]

Its pretty common for those bulb filters to fade,dry rot or melt after 50 years..

 

[Drumaniac]

V

Its pretty common for those bulb filters to fade,dry rot or melt after 50 years..

I have also faded over the past 50 years