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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 10:09 am
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bluesky636 wrote:
I'll be blunt. This is the problem. You are "guessing" at what you should do next instead of following a logical troubleshooting process.....I'm sorry to say this, but I really think that you are in over your head at this point and should take the amp to a professional for an evaluation and possible repair.

fretworks wrote:
It's Alive :D
She is alive and strong.
Q1 was the problem

Wrong again Bill, maybe you'd be better off sticking to armchair-moderating the forums. :roll:

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 11:36 am
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Nope, I have to agree with bluesky636, the shotgun-guessing-game approach is haphazard at best. The methodical approach is always best over the long haul, and it can get very frustrating when trying to help someone who is jumping all over the place and just guessing.

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 11:41 am
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strings10927 wrote:
bluesky636 wrote:
I'll be blunt. This is the problem. You are "guessing" at what you should do next instead of following a logical troubleshooting process.....I'm sorry to say this, but I really think that you are in over your head at this point and should take the amp to a professional for an evaluation and possible repair.

fretworks wrote:
It's Alive :D
She is alive and strong.
Q1 was the problem

Wrong again Bill, maybe you'd be better off sticking to armchair-moderating the forums. :roll:


Maybe you should learn something about amp repair or at least how to read:

bluesky636 wrote:
fretworks wrote:
I have confirmed continuity to ground after r20, so am I right to be certain that something is shorting or opened to ground?.....

Q1 how do I test, and can this be removed to see if is the problem?


Q1 functions as a muting circuit when switching between normal and drive channel. When switched, the signal path is momentarily shorted to ground. If you are measuring a short from the output of R20 to ground, Q1 is either shorted or there is a problem in its power supply that is keeping it active. If you simply run a jumper from the output lead of R20 to the input lead of C14 as stratele52 suggested, you can jumper around the power amp in jack and verify continuity to the phase inverter input without removing any parts.


The OP is lucky he didn't break more than he fixed in his troubleshooting. But I doubt you would understand. I think I hear the denizens of the Lounge calling your name. They miss you.

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 12:42 pm
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bluesky636 wrote:
I think I hear the denizens of the Lounge calling your name. They miss you.


:lol: :lol: :lol:

Arjay

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:13 pm
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bluesky636 wrote:
The OP is lucky he didn't break more than he fixed in his troubleshooting.


Seems like the OP did just fine. So what's the deal anyway, do you think fixing amps is in your DNA, or did you have to learn it by asking questions too? I'm not sure if I've ever met a more condescending $@!&#.

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:15 pm
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shimmilou wrote:
Nope, I have to agree with bluesky636, the shotgun-guessing-game approach is haphazard at best. The methodical approach is always best over the long haul, and it can get very frustrating when trying to help someone who is jumping all over the place and just guessing.


Some people just have no clue what it takes to diagnose a vacuum tube amp, or any amp for that matter, in person or over the Internet. I'm not referring to the OP. :wink:

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:25 pm
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strings10927 wrote:
bluesky636 wrote:
The OP is lucky he didn't break more than he fixed in his troubleshooting.


Seems like the OP did just fine. So what's the deal anyway, do you think fixing amps is in your DNA, or did you have to learn it by asking questions too? I'm not sure if I've ever met a more condescending $@!&#.


Have you looked in the mirror lately?

Tell us, in what amp threads have you provided any meaningful advice regarding building, modding, or repairing?

As far as my DNA goes, no, but the degree I earned in electrical engineering back when tubes were still part of the curriculum along with 35+ years as a system engineer working mostly in the integration and test of both guided missile weapons systems and other classified government systems have kind of helped out a bit. Building and modifying several amps (and writing detailed threads about it here) has proven useful also. Where did you get all of your amp knowledge from?

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:27 pm
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Retroverbial wrote:
bluesky636 wrote:
I think I hear the denizens of the Lounge calling your name. They miss you.


:lol: :lol: :lol:

Arjay


Strings 10927 is on my ignore list, but I find his posts so worthwhile (they really make me laugh), I can't help but read them. I don't know why he has started posting in the amp forums since he is clearly out of his league.

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:39 pm
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I'm not going to get caught up in your BS bluesky636. Just don't ever call me for help with your computer and I'll be sure not to look for any of your help with a tube amp. Good day.

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 2:53 pm
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strings10927 wrote:
I'm not going to get caught up in your BS bluesky636. Just don't ever call me for help with your computer and I'll be sure not to look for any of your help with a tube amp. Good day.


Deal! :lol: :lol: :lol: :lol:

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 3:40 pm
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bluesky636 wrote:
strings10927 wrote:
I'm not going to get caught up in your BS bluesky636. Just don't ever call me for help with your computer and I'll be sure not to look for any of your help with a tube amp. Good day.


Deal!


Works for me too!

:wink:

Arjay

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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Mon Dec 30, 2013 6:31 pm
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stratele52 wrote:
fretworks wrote:
Q1 appears to be internally shorted to all three legs. Out of the circuit ?

I tested cr2 and cr3 in reverse bias with a couple of 9 volt batteries and a 1k resistor.
Scematic shows cr1 and cr2 at 15v.
They tested 14.7 and 14.9
They seem fine.

You are very qualified ! Congrat



Fretworks, Did you find the reason for all three legs of that FET to short out? I kinda find this hard to believe, unless you had one bigtime short in the board. These FET's often are used in a current limiter function, as well a switching funtion. So maybe a big current short to ground fried the FET?

Thanks!


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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Tue Dec 31, 2013 5:16 am
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BMW2002Ti wrote:
stratele52 wrote:
fretworks wrote:
Q1 appears to be internally shorted to all three legs. Out of the circuit ?

I tested cr2 and cr3 in reverse bias with a couple of 9 volt batteries and a 1k resistor.
Scematic shows cr1 and cr2 at 15v.
They tested 14.7 and 14.9
They seem fine.

You are very qualified ! Congrat



Fretworks, Did you find the reason for all three legs of that FET to short out? I kinda find this hard to believe, unless you had one bigtime short in the board. These FET's often are used in a current limiter function, as well a switching funtion. So maybe a big current short to ground fried the FET?

Thanks!


I aks this question dec 25 ; reading short out of circuit ?

No answer.


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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Thu Jan 02, 2014 10:34 am
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Happy New Year!!!

I have been very busy and unable to respond until now.

fretworks wrote: Q1 appears to be internally shorted to all three legs.
stratele52 wrote: Out of the circuit ?
On Dec 25th I (fretworks) wrote: Yes out of circuit.

BMW2002Ti wrote:
Fretworks, Did you find the reason for all three legs of that FET to short out? I kinda find this hard to believe, unless you had one bigtime short in the board. These FET's often are used in a current limiter function, as well a switching funtion. So maybe a big current short to ground fried the FET?

I did not find a reason.
I went through the whole circuit all the way out to the footswitch jack.
All components tested within spec and there is complete continuity of signal.
I ordered replacement jfet.
Q1 replacement jfet111 is soldered in and amp is 100% functional with no problems and sounds great!

I mentioned in my very first post that I had replaced some bad resistors. these might have been subject to the same possible surge, lightning?
As a reminder, I picked this amp up in a trade. Previous owner said it just died one day.


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Post subject: Re: 1993 blues deville 2 x12 low to no volume i need help
Posted: Thu Jan 02, 2014 10:56 am
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Thank's for answer.


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