Just a few more questions about my amp repair

[Stellasstillarat]

I'm gonna tighten down every screw inside the amp. I'm also gonna disconnect the fan and run the amp without it for about ten minutes. I will not have it hooked up to a radio I know not to key it up without the fan running. Weather its the fan causing the buzz after ten minutes of use I don't know. I hope I will find out. I will clean it and lubricate the fan/berring while it's disconnected. Vk also suggested I glue or lacquer the transformer. Can someone tell me what type/brand of glue/lacquer I should purchase? Which one is better glue or lacquer, and how do I apply the glue/lacquer on the transformer? How long should I let the glue/lacquer dry before using the amp? I'm not sure but I think the amp is buzzing louder than last night yet it still starts off nice and quiet only to begin buzzing as time goes by. I have a friend that will be helping me on Saturday. Thanks to vk, captain killawatt and all the rest of my wwdx friends that always come through with excellent answers to my questions. P.s. My brother always said I had a face for radio.

 

[vkrules]

Not that critical. I have used thread locker ,epoxy, contact cement, Iv'e even stolen , I mean borrowed ,the daughters clear nail polish . doesn't have to be super strong just dry enough to stop the laminations vibrating.In recent times Iv'e had several PSUs that I have had to lacquer the lamination ends . Never had that problem years ago they all had 1/8 inch thick lacquer on them, I guess modern cost cutting is to blame.Might not be that but its worth a look. You can usually see if its loose or not.Another thought might be to check the bridge rectifier one of mine starts to buz just before it goes Boom

 

[Captain Kilowatt]

I used regular old polyurethane wood finish on one transformer one time. It worked.

 

[Stellasstillarat]

since I won't be opening the amp until Saturday, I did a couple of test last night. It made me think the fan might not be the culprit. I turned the amp on and let it run without keying it up. Here's what I found. After it ran for about 20 minutes it began a slight buzz as aposed to when i turn it on and begin keying it and sending a signal through it emietly,at that point it starts to buzz in about three minutes. It took the amp one hour to buzz as loud as it does after three minutes of keeping it, and even after the hour it didn't buzz as loud as it does when I heat it up quickly by sending a signal through it. I'm sure the amp doesn't reach the temperature it does when it's being keyed as apossed to just sitting there power on not being keyed. After an hour I shut it down and noticed that the fan continued to spin for a few seconds yet made no buzzing sound the instant I cut the power the buzz ceases,the only sound the fan makes is the sound of a fast spinning fan slowing down then coming to a stop. As all the advice I received, this is what I'm gonna do, tighten down all interior screws, disconnect the fan and run the amp (no carrier through the amp) for a bit to see if it buzzes without the fan running, lubricate the fan/berring and glue/lacquer the transformer. So does anything I mentioned about the testing and results I listed while running the amp without keying it give you a better idea of what the problem may be? one more question. What is and how do i recognize the bridge rectifier? Once again I want to thank all who took the time to share there knowledge and help me. The combined knowledge of all wwdx members is infinite. best site, best members, hands down!
UOTE="Captain Kilowatt, post: 497376, member: 39"]I used regular old polyurethane wood finish on one transformer one time. It worked.[/QUOTE]
La

I used regular old polyurethane wood finish on one transformer one time. It worked.

 

[Captain Kilowatt]

The fact that the noise stops the instant you turn it off means it it indeed power supply related and not the fan. It seems that something is buzzing as it gets hot as indicated by the fact it takes longer and is not as bad when it is just sitting there on and not keyed up generating heat. The bridge rectifier should be the first component connected to the transformer secondary wires and will have a large capacitor connected to it as well. Be careful as that capacitor may still have a charge on it. It may only be 19-22 volts or so but if you accidentally short it to ground it will make a hell of a bang and you run the risk of requiring new underwear should that happen. Personally I am still leaning towards the loosened hardware somewhere.