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

All times are UTC - 7 hours



Post new topic Reply to topic  [ 32 posts ]  Go to page 1, 2, 3  Next
Go to page 1, 2, 3  Next
Author Message
Post subject: 100th post need some opinions with photos
Posted: Fri Dec 06, 2013 9:38 am
Offline
Professional Musician
Professional Musician

Joined: Wed Dec 15, 2010 7:06 am
Posts: 1662
Ok being this was my first post viewtopic.php?f=12&t=47799 I thought it right to post my 100th here. I need to dig in to my 69 SFSR deeper. I have been in this amp changed tubes changed the caps under the doghoues checked Bias (still not happy)I do know how to solder and know how not to kill myself in there, I am very weak on reading schmatics, but time to learn. I am looking for a step by step manual or book nice to have a DVD teaching me, one that will not go way over my head but will help me troublshoot, measure voltage, resitance and anything else I should know about my 69SFSR . I was not the first person in there as the caps under the dog house had 3 Malorys and 2 Japanese ones and residue all over the inside cap, wrong power tubes 1 6L6GB and 1 6L6 GC in bad shape It is somewhat better but not where she should be, Here are some gut shots
Image

Image

Image

Image

Image

Image

Image

Image

Image

Image


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: 100th post need some opinions with photos
Posted: Fri Dec 06, 2013 10:50 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
Where is the amp sonically at the moment? Did any of the servicing and maintenance that you performed previously improve the tone?

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: 100th post need some opinions with photos
Posted: Fri Dec 06, 2013 6:50 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
mud, Happy 100th!

Do you have photos of the caps under the doghouse? You need a solid power supply unit & bias supply before any other changes. IMHO.


Thanks!


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 3:23 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
Mud , what is the problem with your amp ? If not broken , don't fix it .

There are no videos ( IMO ) to show you how .

Caution ; lethal voltage in tubes amps . Even is unplug since many hours


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 6:55 am
Offline
Professional Musician
Professional Musician

Joined: Wed Dec 15, 2010 7:06 am
Posts: 1662
Retroverbial wrote:
Where is the amp sonically at the moment? Did any of the servicing and maintenance that you performed previously improve the tone?
Arjay


Yes after I changed out the caps under the doghouse and put in proper tubes,she most definetly got louder

BMW2002Ti wrote:
mud, Happy 100th!

Do you have photos of the caps under the doghouse? You need a solid power supply unit & bias supply before any other changes. IMHO.


Thanks!


No I did not take any photos under the dog house after I changed them out,all spauges, but the amp did wake up

stratele52 wrote:
Mud , what is the problem with your amp ? If not broken , don't fix it .

There are no videos ( IMO ) to show you how .

Caution ; lethal voltage in tubes amps . Even is unplug since many hours


Thank you I am well aware of the lethal dangers of tube devices Yes I go one hand behind my back. Im good at Chop and Swap,for many years I worked on a bench where the tech would just give me parts and location and I would replace them without knowing why, so I have some experience but not enough knowlege

The Issues:
1) I can't get the bias past 27ma, it has a balance pot
2) Vibrato has a POP POP motor boating to the speed,volume with this issue stays the same I can bring the volmue up and my guitar will drown it out
3) now here is a wierd one when the reverb pedal is pluged in to the unit I can not get any reverb, pedal button in or out ,does work for the vibrato even when I switch the pedals input as reverb side to the vibato side, so I know the pedal works I even metered the pedal.When I pulled the RCA from the Reverb where the pedal goes,the reverb works, so I have reverb and when I dont want it I just plug the pedal back in , but that is not right
These are the major problem, cosmedics is is anothe issue but that can wait, not sure if I am going to recone the speakers or eventualy get some Webers but that will need to wait

thank you all
mud


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 7:10 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
" I can't get the bias past 27ma, it has a balance pot. "

Prolly tired output tubes (6L6GC) and/or rectifier. What are the plate voltages on the anodes of those 6L6GC?


" Vibrato has a POP POP motor boating to the speed. "

Bad wiring layout around the 12AX7 associated with the vibrato section. Try various 12AX7's in this position. I've found the vibrato's motorboating can be related to the specific 12AX7 used.



" When I pulled the RCA [plugs] from the Reverb [coax cord] where the pedal goes,the reverb works, so I have reverb. "

Most likely, you have a problem with the wiring in that foot switch. Try remving the rubber-plastic cover and inspecting the wiring and switches.


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 7:41 am
Offline
Professional Musician
Professional Musician

Joined: Wed Dec 15, 2010 7:06 am
Posts: 1662
BMW2002Ti wrote:
" I can't get the bias past 27ma, it has a balance pot. "

Prolly tired output tubes (6L6GC) and/or rectifier. What are the plate voltages on the anodes of those 6L6GC?
The 6L6 are new (electro-harmonix) the rectifier is old I guess I should inveset in a new one, Plate voltage is 430vdc

" Vibrato has a POP POP motor boating to the speed. "

Bad wiring layout around the 12AX7 associated with the vibrato section. Try various 12AX7's in this position. I've found the vibrato's motorboating can be related to the specific 12AX7 used.
I will give that a try I do have a large supply of 12AX7 RCA's, Tungsol, IBMs, various other old ones and some new electro-harmonix



" When I pulled the RCA [plugs] from the Reverb [coax cord] where the pedal goes,the reverb works, so I have reverb. "

Most likely, you have a problem with the wiring in that foot switch. Try remving the rubber-plastic cover and inspecting the wiring and switches.

I have taken it apart metered it tried it in a different amp the pedal does work fine

mud


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 9:38 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
BMW2002Ti wrote:
" I can't get the bias past 27ma, it has a balance pot. "

Prolly tired output tubes (6L6GC) and/or rectifier. What are the plate voltages on the anodes of those 6L6GC?


[ .


Yes and....no

I had same problem with Pro Reverb ( Black face ) same cold bias with new tubes , I just change the resistor on pot for a lower value . The resistor with one end solder to pot body . My Pro Reverb have a 27 K and some PR have 15K . I put 15k and biasis right.

NOT same mod here. You have already a 15 K and a Balance pot .
First check with new 6L6. If not better replace the 1K resistor on bias circuit board by a bigger value ( 1.2 K ) Be carefull not to heat too much the diode rectifier.

Or less expensive , keep old tube an put a 1.2 K resistor.
____________________________________________

Easy mod you can do ; Balance pot to Bias adjustment pot


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Sat Dec 07, 2013 9:40 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14049
Location: Province de Québec, Canada
BMW2002Ti wrote:


" Vibrato has a POP POP motor boating to the speed. "

Bad wiring layout around the 12AX7 associated with the vibrato section. Try various 12AX7's in this position. I've found the vibrato's motorboating can be related to the specific 12AX7 used.
.


+1000
These amp need a good cleanup in wiring .


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Thu Dec 12, 2013 3:46 pm
Offline
Aspiring Musician
Aspiring Musician

Joined: Thu Dec 12, 2013 2:54 pm
Posts: 619
Mud,

I'm celebrating your 100th post with my first.

That bias balance adjustment just ain't right. Looks like someone tried to change it to a bias adjust, but the way it looks, it won't work right.


JMHO,
Vinyl


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Thu Dec 12, 2013 6:36 pm
Offline
Rock Star
Rock Star
User avatar

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

Welcome to the Forum! :D

It's a stock AB568 layout. It just looks a bit odd, as in these years Fender placed some resistors of the bias supply onto a connector strip, instead of onto the tagboard (as in the earlier AB763). Check the layout of the AB568 (two 10K-ohm, with 100k-ohm between the two).


http://www.webphix.com/schematic%20heav ... _schem.pdf


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Fri Dec 13, 2013 2:54 am
Offline
Aspiring Musician
Aspiring Musician

Joined: Thu Dec 12, 2013 2:54 pm
Posts: 619
Beemer,

Thanks, and I stand corrected. :oops:

Apologies Mud.

Vinyl

_________________
"Where confusion abounds, there's money to be made."


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Fri Dec 13, 2013 9:51 am
Offline
Professional Musician
Professional Musician

Joined: Wed Dec 15, 2010 7:06 am
Posts: 1662
First of all I do believe its a AA1069 circuit not sure if that matters
Second would it be this resistor I need to check
Image

Or these
Image

or all 4 and the pot

Thanks
mud


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Fri Dec 13, 2013 11:52 am
Offline
Professional Musician
Professional Musician
User avatar

Joined: Sun Aug 05, 2012 9:50 am
Posts: 1399
Happy 100th. :)

_________________
I have some Fender gear.
(Telecaster, Jaguar, Villager 12 String. Mustang l, Bronco, SCX2, Rumble 350, HRDIII, Rumble 2x8 Neo Cab)
http://www.reverbnation.com/modwiz


Top
Profile
Post subject: Re: 100th post need some opinions with photos
Posted: Fri Dec 13, 2013 1:06 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
mud wrote:
First of all I do believe its a AA1069 circuit not sure if that matters
Second would it be this resistor I need to check
Image

Or these
Image

or all 4 and the pot

Thanks
mud


I'd check everything in the biasing circuit, including the incoming voltage from the power supply.

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
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 32 posts ]  Go to page 1, 2, 3  Next
Go to page 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: