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I haven't been able to get it in the full volume mode at all lately... Just half volume... All the tone controls seem to work... It is quiet... Just half volume...
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That's good then. Have you ever tried to fix something that won't go wrong? Frustrating doesn't come close...Originally posted by Danglin' Fury View Post
Experience is something you get, just after you really needed it.Comment
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Yes sir I have... Lol! And you are correct... Frustrating doesn't touch it... Lol!Comment
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I have access to the 2 22nF coupling caps that are in the phase invertor... I'm going to change those tomorrow and see if that fixes the problem... The effects loop board seems to be ok... The jacks as well... When the amp came to me, the customer said the mains fuse blew and there was a dead power tube... I measured everything on the power board and it is ok.... As the power tubes are all operating as advertised...Comment
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Find those two caps on the board. Apply a steady signal to the amp. Now see if the signal is present on the phase inverter side of those caps, and then see if it is present on the power tube side of those caps. That will tell you if the caps are diminishing the signal
I don't know what operating as advertised means. All glowing heaters? Did you check for B+ on the screen of every power tube? Pin 4.Education is what you're left with after you have forgotten what you have learned.Comment
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Yes sir... ~450 Volts DC on pin 4 of the power tubes....Comment
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Anything? Also earlier in the thread, I took some measurements of the output transformer... The primaries look a bottle low to me, anyone else?Comment
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DC resistances don't tell you much. The best methods are probably (a) measure the primary inductance or (b) ring the transformer see RG Keen's method.Originally posted by Danglin' Fury View Post
Have you measured the grid drive yet?Experience is something you get, just after you really needed it.Comment
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I will do the lightbulb test, although its proving difficult to find a neon bulb locally... Here's the deal... I work at an electronics shop repairing and modifying high end analytical equipment for the battery test industry... Between that and my sons visiting every other day I have very limited time to work on amps, although I love doing it... Someday I hope to own my own shop but I digress... I just found out the shop I work in has a signal generator so tomorrow I'm gonna put in a 1kHz sine and see where the signal gets small... Man I'm telling you... The voltages in this amp and the resistance readings are all good... I've measured the resistance on all the caps (R.G. Keen says below 15 k ohms = bad caps) all readings are well above that...Comment
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Ok... Just applied a 1kHz sine wave into the Bugera.. Aaaaaaand it started red plating... Now its half volume AND the power tubes are red plating... Anything? Anyone?Comment
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Aaaaaaaand with the output transformer in the amp, still connected, I have about 237K ohms resistance between all taps of the primary measured to the secondary taps....Comment
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Does the red-plating only happen with signal?
Do you have any other type of OT you can sub in there to test?Originally posted by Enzo
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Disconnect the negative feedback lead before measuring.Originally posted by Danglin' Fury View PostComment
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The red plating most definitely only happens with a signal present... I may have a friend that has a spare OT he can loan me... Im gonna see if the bias caps are leaking today around 11:00-11:30... So I Will be able to eliminate that... Perhaps I can get another OT this evening... If it is the OT, any place I can find one for under $125?Comment
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And thank you sir... I completely forgot to do that...Comment
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