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Peavey Windsor to JCM800 Conversion.
#21
Like this?

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#22
The guy who authored the mod positions his next to the P.T. which makes sense. Shortest path between it and the choke.
My Vase amp has a choke similarly positioned.

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#23
Works for me.
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#24
I'm guessing it doesn't matter which way the choke is wired right? There are 2 wires.
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#25
I don't think so. Either way round should work.
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#26
Holy shit! This is the first time I've had the power section PCB lifted. The would explain why that pair of el34s went bad so fast. Just something else to fix. I'm gonna do a bit of probing before I go any further. If those are burnt, I'm sure something else is. 3 of the 4 are burnt.

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#27
That was fortuitous, lifting the board.
Replace those with higher wattage ones, if not wire wound higher wattage.
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#28
All I have are 1/2W carbon 10ks. Looking at the size difference, the originals are are only 1/4W. These should workI hope.
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#29
They should be better than the 1/4 watt ones. [ 1/4 watt ones, that was cheap of them, especially on output valves. Almost designed to fail ]


I've fixed three of the same model sattelite box in the last couple of months with exactly the same problem. It seems that if they get a power surge it goes straight past the fuse and hits a couple of 1 meg resistors in series that bleed off some low power from the main primary voltage in the power supply, blowing the first one out. They are too low wattage [ 1/4 watt ] I've been replacing them with half watt ones.
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#30
Damn it. It's just one thing after another this morning. R47 on the output breakaway is giving me shit.

I test my resistors before and after I install them to make sure everything stays good. All 3, 100k 1/2W resistors I have put in have changed value to the exact same thing. After they are soldered in, they drop to exactly 32.8k. When I desolder them and test again, they show 72k. All 3! I only had 3.


These are wire wound good resistors. There is no way in hell I'm burning these with 3 seconds of iron heat. I had to pass a brutal NASA spec soldering test, and I haven't  burned a single component in the almost 5 years since. WTF is going on?

I had to stop and turn my iron off for the day. Not evenclose to done either. All the old parts are out, but nothing has been put back in yet. Maybe I'll have better luck tomorrow.

GV, would 110k be close enough if I parralel 2, 220k for that spot? And, how was that amp even running with 3 of those bias resistors burnt and open? Shouldn't a fuse be blowing?

Edit:

Never mind on that R47 thing. Once I disconnected P401 it gave me the right value. I just happened to notice that there was resistor in parallel on the other end. A variable resistor at that. I had yet another dumbass moment.
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