Highlighting is not just checking values; you need to confirm every connection makes the connection(s) it's supposed to make, and only what it's suppose to.bobtait wrote: ↑Sat 08/09/25 5:14 pmThe original is the one that is in it now. I only patched in the new one for a few minutes. But I am going to keep going through the circuit too. I checked the values of every part I put in as I was doing it but I will check them again. It is pretty easy to just patch in the other OT too. I'm just glad it's making any kind of noise at this moment. And thanks!
Robinette 6V6 JCM 800 build problem
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Re: Robinette 6V6 JCM 800 build problem
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'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright
Modern Ground Schemes
Soldering Technique
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Amplifier Tools & Parts Info
Troubleshooting Basics:
Step 1: Remove and discard all JJ tubes.
Step 2: Highlighter test.
Step 3: Use a Voltage Chart from the downloads section to test your voltages.
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Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info
Troubleshooting Basics:
Step 1: Remove and discard all JJ tubes.
Step 2: Highlighter test.
Step 3: Use a Voltage Chart from the downloads section to test your voltages.
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Re: Robinette 6V6 JCM 800 build problem
This advice is gold - doing exactly this helped me trace a missing earth connection in my bias supply. The layout diagram I was following made it hard to spot.JMPGuitars wrote: ↑Sat 08/09/25 5:21 pmHighlighting is not just checking values; you need to confirm every connection makes the connection(s) it's supposed to make, and only what it's suppose to.
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Re: Robinette 6V6 JCM 800 build problem
So.. is it making sound now?
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"THIS should be played at high volume..preferably in a residential area"
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bobtait
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Re: Robinette 6V6 JCM 800 build problem
Yes, it is making sound now. My tone generator will play whatever frequency I choose through the speaker. However, the amplitude is very low. If I increase the the input voltage it gets louder but I am getting up to 8 volts on the input which is far beyond a guitar signal. I have not had time to get back on it for a few days. I will patch in the new output transformer just to make sure that the first one was not damaged with the shorted output jack. And I will trace the entire circuit again. I feel that the culprit will reveal itself. It could well be a damaged OT. I sure put it through hell. I will post as soon as I get back into it.
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Re: Robinette 6V6 JCM 800 build problem
Maybe a far fetched idea.. but maybe plug in a real guitar?
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bobtait
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Re: Robinette 6V6 JCM 800 build problem
I plugged my Les Paul in as well as the tone and you could hear it like a whisper just enough to tell if you put your ear right next the speaker.
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Re: Robinette 6V6 JCM 800 build problem
When in doubt, check all voltages.
0 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright
Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info
Troubleshooting Basics:
Step 1: Remove and discard all JJ tubes.
Step 2: Highlighter test.
Step 3: Use a Voltage Chart from the downloads section to test your voltages.
Web Design: flashydragon.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale
Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info
Troubleshooting Basics:
Step 1: Remove and discard all JJ tubes.
Step 2: Highlighter test.
Step 3: Use a Voltage Chart from the downloads section to test your voltages.
Web Design: flashydragon.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale
