HRDx Issue?

[km5jh]

Wondering if anyone might have some thoughts on this. I've got a 3 to 4 year old Hot Rod Deluxe 1X12 that I've been trying. I noticed that one of the 6L6 power tubes in XV4 socket was not glowing as the other in XV5. I thought the tube was bad so to verify this I switched the tubes from one socket to the other to see what would happen . When I powered up the amp the one I thought might be bad was glowing in XV5 but the other "good" one was not glowing in socket XV4. This tells me that both tubes may be OK but maybe there is a problem with tube socket XV4. Am I missing anything here? The amp still works but there must be something wrong. Any thoughts on this? I just checked the bias and it is setting at 34mV's. This is low and probably reflects one live power tube. Thanks, KM5JH

[NTBluesGuitar]

You're likely in need of some attention on your tube socket pin solder connections.

But, it's under warranty, so have Fender fix it!

[km5jh]

You're likely in need of some attention on your tube socket pin solder connections.

But, it's under warranty, so have Fender fix it!

You may be right on the pin connections. I thought it might be under warranty but according to my son, it's past 5 years old. I'll examine the socket and see if I find anything. Not sure what else it might be. Thanks, Tony

[NTBluesGuitar]

Well, it could be any of the green wire connections from the power transformer through the tube socket PCB.

Specifically look at pins 2 and 7 on the power tubes.

[km5jh]

Well, it could be any of the green wire connections from the power transformer through the tube socket PCB.

Specifically look at pins 2 and 7 on the power tubes.

Will do.... Thanks, Tony

[km5jh]

UPDATE....

I checked V4 and found 3 pins with broken solder contacts (3 side by side). I de-soldered the 3 pins and cleaned them and then re-soldered with 94/6 tin-silver. I powered up the amp and mission accomplished. I set the bias at about 68mV's. I'd be curious to hear what bias folks are using with the GT's. I have some JJ 6L6 tubes on the way and will switch out the GT/Sovteks when I get the JJ's in. What bias setting is good for the JJ's??? Thanks for your input.... Tony

[FrankJohnson]

UPDATE....

I checked V4 and found 3 pins with broken solder contacts (3 side by side). I de-soldered the 3 pins and cleaned them and then re-soldered with 94/6 tin-silver. I powered up the amp and mission accomplished. I set the bias at about 68mV's.

this is the most common scenario I have encountered.

I biased a little hotter than that....and it plays fine.

[NTBluesGuitar]

I set the bias at about 68mV's. I'd be curious to hear what bias folks are using with the GT's. I have some JJ 6L6 tubes on the way and will switch out the GT/Sovteks when I get the JJ's in. What bias setting is good for the JJ's???

Biasing is set to a percentage of maximum plate dissipation, not a mV reading. The mV reading is a result of bias, not a process to bias.

There's somespecific bias information in the amp sticky thread.

[km5jh]

Biasing is set to a percentage of maximum plate dissipation, not a mV reading. The mV reading is a result of bias, not a process to bias.

There's somespecific bias information in the amp sticky thread.

True... the mV is a measure at the test lead on the PCB and is a indication that is commonly referred to. I didn't go into detail. I'll check out the area you mentioned... Thanks, Tony

[km5jh]

this is the most common scenario I have encountered.

I biased a little hotter than that....and it plays fine.

Thanks.... Tony