6021W subminiature tubes change - problems

[Bazzy]

Hi everyone,

Last night I decided to change the standard Philips 6021W tubes of my AUdio Aero Capitole cdplayer/DAC.
These tubes have been playing for 13 years now.

I had bought raytheon 6021W tubes as a replacement, but after I had soldered them in they don't work, they dont even glow.

I kept to the same pin layout as the philips tubes, since I thought the pin layout of the same type of tube should be the same.

Am I overlooking something?

Does anyone have experience with these tubes?

 

[MagicBus]

Possible misalignment? Easy to happen with these tubes. You can find the heaters pins with a DMM's buzzer.

 

[Boydk]

My bid too. You can´t always change the just by the looks or a dot. Take MagicBus´s advice and find pins 3 & 6 with the dmm. Then the rest should be easy

 

[Bazzy]

Thanks! I didn't know that.

The reference point I used was the slighty bigger gap between two of the eight pins.
I thought that gap marked the difference between nr.1 and 8.

But, if I find nr 3 and 6 with the buzzer, how will I know which one is 3 and which one is 6?

This maybe a stupid question but I have absolutely no knowledge of electronics.

But I can make a good solder joint : -)

 

[MagicBus]

The heaters pins should leave two pins between them which are both cathodes.

 

[Boydk]

Exactly.... with pin 3-6 you have 7-8-1-2 on one side and 4-5 on the other side. If that´s too hard, then you maybe should leave to a qualified technician

 

[Bazzy]

Exactly.... with pin 3-6 you have 7-8-1-2 on one side and 4-5 on the other side. If that´s too hard, then you maybe should leave to a qualified technician

: -) OK, thanks : -)

 

[Kay Pirinha]

As the pin (or wire) arrangement is symmetrical, and both triodes are equal, it doesn't matter if #3 really is #3 or #6 - or vice versa .

Best regards!

 

[MagicBus]

Exactly.... with pin 3-6 you have 7-8-1-2 on one side and 4-5 on the other side. If that´s too hard, then you maybe should leave to a qualified technician

Let's give it a try! I found some photos in the internet that show a kind of pins designation on the PCB. Something like a reversed T for plates, a Π for cathodes and the alike, all typical for tubes schematics. But the photos are not the best. Could Bazzy take a good photo of the tubes area that that would show what's written on the PCB? Even better with the tubes removed. First guess is that pins 1 & 8 are the first closer to the big yellow capacitors

 

[audiopro]

Be very careful. Those board traces are very fragile. Use solder wick to un-solder.
No offence, but I've seen too many owners try to do this themselves and seriously damage the board. Find a good tech. Those circuit boards are irreplaceable and easily damaged.
Chances are you put one or both in wrong. The filaments are wired in series. If one is wrong, neither will glow.