Troubleshooting help - more amp woes

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Illumination
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Joined: Fri Apr 09, 2021 5:41 pm

Troubleshooting help - more amp woes

Post by Illumination » Fri May 07, 2021 1:47 pm

So I recently posted a thread about my 6505+ 112 combo which was constantly blowing fuses. After much troubleshooting and parts replacing, I thought I'd got it working last night, as I replaced some capacitors and when I powered it up, the fuse held. However, it was late at night and I didn't want to play it so I left it til today to test how it sounds. The answer is it's not right at all!

When I power it up, once I hit the standby switch to the play position, the speaker just starts to buzz constantly. Both channels are the same. The post gain control does affect the volume of the buzz. When I plug the guitar into the input, there is some fairly clean guitar sound coming through but I can't get any distortion. If I plug the guitar into the effects loop return instead, there is distortion but it's messy, noisy, crackly, not a proper tone. I have literally no idea what this could be. I guessed that I must have created a short or something while I was replacing the parts that I've swapped out, but I've been back through it and couldn't see anything.

Anyone got any ideas? :(

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Enzo
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Location: Lansing, Michigan

Re: Troubleshooting help - more amp woes

Post by Enzo » Fri May 07, 2021 4:12 pm

Or perhaps a ribon connector is off a pin or even a connection broke on one.

Illumination
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Joined: Fri Apr 09, 2021 5:41 pm

Re: Troubleshooting help - more amp woes

Post by Illumination » Sat May 08, 2021 8:05 am

I've reflowed some of the solder joints that I'd been working on and I've got the amp fully functional, but with this constant background buzz/hum. I've had the amp powered up out of the chassis and I've been tapping and poking all the caps and moving the cables to see if there's any clues but nothing. I wonder if this is a grounding issue, but I can't find anything. I was trying so hard to avoid having to take this to a tech because I can't really afford it, but I'm starting to think I'm going to need to accept defeat

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