old fender amp making weird noises

Hi! I forgot to say sorry to everyone, about the fact I did not come here for a long time, but I've been really busy and had internet provider problems too.

Here my problem... Some weeks ago my Fender Bandmaster (blackface, born '64) started makink some noises when idle. They seemed random low-frequency growls, somehow. Anyway, after some time they got more and more loud, and less rare. last time I switched it on, after 20 minutes these noises became continuous and pretty loud too. Swithced it off, to avoid any kind of damage.
Now: I think that the power valves could be dead, at least one of them, even if they did not seem to produce strange colours or else. Has anyone an idea of what it could be? Keep in mind that condensers are still original. I do not know if these noises are due to dead valves, dead condensers, maybe a dead resistor.....
Thanks for your help!

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Another (easier to fix) possibility occurs to me. Your V1 preamp valve may have gone microphonic. This is quite common, especially with the Russian and Chinese types on the market. It usually results in whistles, "whoop" and "boing" noises. Look for the ECC83 or 12AX7 furthest from the power valves and nearer to the inputs, This is V1. Replace it with a new preamp valve from a trusted source if your filter capacitors are not the problem. It may solve your noises. The sparking is definitely something else, though. Dirty valve bases being the most obvious.

Hi bass! Thanks for the advice, I just bought a new preamp valve and will try that soon. I'm replacing the filter caps in these days too, so let's see.
About the crackling noises once the amp is warm...
Could it be one of the resistors connected to the valve base being broken and begin to crick-crack when hot?
In the meantime I bought new valve bases too, so, if the noises do not disappear, I'll try to put them on.
Thanks for yer help!

ok, I did not notice you posted twice, so I missed the first post.
Anyway, I'll try to put some photos here (is it possible to place a photo in the post, or how can I do that?). For now, I sprayed some good (they told me it was) contact cleaner/lubricant on the bases.
I just checked, and on the "+" end of one of the two 70uf capacitors there actually IS a tiny spot of white dust of some kind. I'm going to replace them anyway in these days.
When everything is done, I'll post back what happened. If I can I'll put post pictures too.

Riz, on this forum, you will see that I have posted a "sticky" thread, "Posting pics on Guitarsite". I hope this will help you to put pictures up. Keep in touch or PM me if you have any problems posting pictures. Once you find the problem and solve it, your info would be very useful to other readers here. Good luck, and keep coming back here for opinions and advice :)

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