It is currently Mon Mar 16, 2020 4:52 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3  Next
Go to page Previous  1, 2, 3  Next
Author Message
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 2:47 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
Too true, I'm afraid.

Troubleshooting down to the component level on an eyelet board (or point-to-point construction) is becoming a "lost art". And vacuum-tube theory is seldom taught at engineering schools anymore.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 3:04 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
I would say that a true technician who learn electronics in school and not on the job get the knowledge to repair amplifiers no matter the problem.
Whether printed or eyelet board circuits, does not change the circuit, only the appearance.
Eyelet circuit board are more easy to work on.

Tubes, not even studied at the school, a true technician able to master them with minimal information with Google for example. This is substantially similar to the transistor in theory.

By against a guy trained on the job, will be exceeded if it has not already experienced the same circuit and a similar problem.


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 8:26 am
Offline
Hobbyist
Hobbyist

Joined: Wed Jan 08, 2014 11:18 am
Posts: 12
Attempting to upload pics. Let's see if this works.[img]http://s1334.photobucket.com/user/jazznbluez/media/T2eC16ZIFIeUOmKzBSUssLyBzw60_57_zps825ebadc.jpg.html?filters[user]=138883609&filters[recent]=1&sort=1&o=1[/img]


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 8:39 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
shelshaf wrote:
Attempting to upload pics. Let's see if this works.[img]http://s1334.photobucket.com/user/jazznbluez/media/T2eC16ZIFIeUOmKzBSUssLyBzw60_57_zps825ebadc.jpg.html?filters[user]=138883609&filters[recent]=1&sort=1&o=1[/img]



Not working . You can test by yourself after sending your answer if not ok EDIT or DELETE.

How to post photo....here


forums.fender.com/viewtopic.php?f=2&t=52777&hilit=Nutter%27s+guide


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 8:55 am
Offline
Hobbyist
Hobbyist

Joined: Wed Jan 08, 2014 11:18 am
Posts: 12
Sorry, I see the "preview" button now. Here are a few pics. The one with the caps didn't work out too well. However, you can see the first two on the left in one of the pics. [url][URL=http://s1334.photobucket.com/user/jazznbluez/media/T2eC16ZIFIeUOmKzBSUssLyBzw60_57_zps825ebadc.jpg.html]Image[/url][/url]
[url][URL=http://s1334.photobucket.com/user/jazznbluez/media/T2eC16dzUFIcl9sVUsBSUsr5HQ60_57_zps57674f8e.jpg.html]Image[/url][/url]
[url][URL=http://s1334.photobucket.com/user/jazznbluez/media/T2eC16JzUE9s38-JGBRfsNN59lg60_57_zps03f3931c.jpg.html]Image[/url][/url]


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 9:02 am
Offline
Hobbyist
Hobbyist

Joined: Wed Jan 08, 2014 11:18 am
Posts: 12
This pic of the caps is a little better, but you still can't read the writing. [url][URL=http://s1334.photobucket.com/user/jazznbluez/media/caps_zpsed8dc3e8.jpg.html]Image[/url][/url]


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 9:36 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
shelshaf wrote:
stratele52 wrote:
Retroverial +1

Background noise ; Need new plate resistors on all 12XX7 tubes.

Cracking noise ; tubes'sockets may need cleaning and retensionning .


Plate resistors have recently been replaced. Tube sockets were cleaned.


1- Picture not clear enough to see plate resistors if they are new . Are they ?
Plate resistor was replace by you ?

2- The dog house , where are filter caps , the 2 blue are new ; are the value are good ?
Two brown ones, are originals.
3- The yellow one ; what is is value ?
4- Check 2 resistors ; must disconnect one end , good ore not ?
Caution ; discharge capacitor ; lethal voltage

5- We need to know all Power Supply voltages.
You may need to replace all bypass cap . Double electrolytic 25 mfd , they are black with 2 wire at one end and one wire at the other end . I use Sprague Atom
We can see only 2 on your half amp photo.

6- You may need some new outut tube , Sovtek 5881 are not the best even new ; You have to do some test .
7- Phase inverter tube ; 12AT7 ; check . And all resistor in this circuit ; disconnect one end to read.

Need to see photo of the other half of the circuit .

I hope you give aswer to questions and test 1 to 5 and 7 if not we can't go furter.
Question 6 , need new tubes.


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 9:57 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
The blue reservoir caps appear to be Spragues (they're correctly phased) while the gold GE's look to be OEM. That yellow thingie is anybody's guess. Impossible to tell about those power-rail resistors -- are they the correct value?

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 11:51 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Retroverbial wrote:
The blue reservoir caps appear to be Spragues (they're correctly phased) while the gold GE's look to be OEM. That yellow thingie is anybody's guess. Impossible to tell about those power-rail resistors -- are they the correct value?

Arjay



+1


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 12:31 pm
Offline
Hobbyist
Hobbyist

Joined: Wed Jan 08, 2014 11:18 am
Posts: 12
Any idea why there's a 1/4" jack next to the choke??? I know there's a whole in the back of the chassis next to the vibrato pedal jack. I'm thinking that was once a master volume or mid boost mod. Could the jack and the hole in the back have something in common?


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 2:39 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
That "jack" adjacent to the choke is actually the bias-adjustment pot. Look down into it and you'll see provisions for a flat-blade screw driver.

As for that blasphemous hole on the rear panel, who knows? Could've been a line-out jack, a master-volume control, any number of nefarious-and-unnecessary mods.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 2:44 pm
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Looks as though six plate resistors were replaced with newer carbon comp(the ones forming a "V") The other two along the back of the board seem to be the(darker) originals and the solder at the .1 and .022 caps is undisturbed. JMO, Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 4:19 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Image


The yellow cap on the right looks like it maybe leaking. In any event, check all caps, esp the paper GE ones in the middle for "pimples" and signs of electrolytic fluid leaks on the two sides of the caps.

From the symptoms of your original post, you should rule-out the power caps & resistors under the doghouse, first. It sounds like you may have poor filtering in the gain stage section. So, those GE and the yellow 'lytic caps are suspect. Maybe, just go ahead and replace them. The yellow one looks like an early Sprague ATOM with paper wrapping.

How old are those blue Sprague ATOM caps? I believe that Sprague went to the blue color (from orange-yellow) in the 1980-90's. So those blue ATOMS could be 25 years old.


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sat Jan 11, 2014 5:54 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
BMW2002Ti wrote:
The yellow cap on the right looks like it maybe leaking. In any event, check all caps, esp the paper GE ones in the middle for "pimples" and signs of electrolytic fluid leaks on the two sides of the caps.

From the symptoms of your original post, you should rule-out the power caps & resistors under the doghouse, first. It sounds like you may have poor filtering in the gain stage section. So, those GE and the yellow 'lytic caps are suspect. Maybe, just go ahead and replace them. The yellow one looks like an early Sprague ATOM with paper wrapping.

How old are those blue Sprague ATOM caps? I believe that Sprague went to the blue color (from orange-yellow) in the 1980-90's. So those blue ATOMS could be 25 years old.


Wipe the slate clean and replace them all with a fresh array of F&T's. Don't forget the bias cap.

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Issues with 67 Super Reverb
Posted: Sun Jan 12, 2014 1:49 am
Offline
Professional Musician
Professional Musician

Joined: Fri Jun 26, 2009 6:53 pm
Posts: 2252
Location: Harvard IL
Just want to say that, I agree with Stratele's opinion about formal education. I'm a self-taught amp tech and there is no substitute for the formal education. A Philosophy degree doesn't do much for electronics. Lucky you guys let me hang around !!! Keep Pickin'!!! Art

_________________
None of Us are free, if One of Us is chained !


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3  Next
Go to page Previous  1, 2, 3  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: