Help. My amp is broke! Oh noes!

[mauser]

Ok. Despite being mortally wounded today, I was able to hobble to radio shack.

I procured:

40 watt soldering iron with pencil tip.
Solder sucking bulb.
96/4 tin/silver solder .032 gauge
some pre made alligator clip leads.  well insulated.
Some DeOxit D5
1k 1 watt resistor for discharge tool
some  shrink wrap..may have some in garage...but motorcycle in the way of that tool box. I cant move it right now.


I'm going to tin the iron and cut one of those alligator clip leads in half and solder the resistor inline...cover the whole deal with shrink wrap.  Then I should be able to drain the caps if I find voltage.

Any flaws or ideas while I make up my discharge tool?

Then I'll pull the chassis. With pics. Might as well document everything, maybe a picture will help someone putting one of these back together or something.

Elsa checking stuff out.


Mauser and Zeus have to have a look as well.

[galaxiex]

Nice guitars! 

I have the Epiphone Tony Iommi Signature guitar in what  else... Black...
I got the last one in Canada after they went out of production. Not that that is any big deal... You can still find them on Ebay etc...

[mauser]

I love the Iommi Guitars!    I have a set of Iommi signature pickups from one a guy took apart and painted the whole guitar with a Sabbath theme...why he would take the black chrome pickups in it out...I do not know...he put some purple ones in it now.  I got those pickups for $50 on ebay make an offer!!   Real Gibson 4 wire Iommi's.   I'm gonna put them in my SG with coil tapping pots and have a screamer.

I have the discharge tool made.  It measures 970 Ohms resistance.   Also temporarily soldered one of those alligator clip leads to the black lead on my Multimeter.  Now I can ground it on chassis and probe one handed...right handed...lol.

Going to pull the chassis after dinner.

Am I missing anything?  I'm not plugging it in and doing any testing live till I get schooled by you guys on what to do. Just checking caps for voltage and discharging and inspection all unplugged.

[mauser]

Chassis out.   Pics coming.

[mauser]

[mauser]

So the next obvious move is to take the board off the chassis to inspect the back of it.   Looks like I have to take all the knobs off and the heat sink deal screws from under the chassis.  And slip board back and flip it over.

[mauser]

So guess what?   I FREAKING FIXED IT!!!!!   WHOOOO HOOOOO 8| <3) :dbtu: :tu: :duh xP 8| :loco <3)

[DrGonz78]

You have to add more than all those emoticons as to what fixed it!! lol. Of course very glad to hear that it works now :dbtu:. But seriously we're all on the edge of our seats wondering what was wrong.

[mauser]

Pics uploading and video.

[mauser]

I was pretty excited.   So it was a solder joint on the filter cap.  Only one on board that looked funny.  Like fractured around the perimeter. Could barely see it.  There was no voltage higher than .2 v   So I went ahead and re-soldered all the 4 joints on the 2 filter caps.  I cleaned the pots while I was at it and the input jacks.  Put it back together...said a prayer.  Bam.  Flipped the switch and was rewarded by the amp gods.

I got sooo lucky...cause I don't know a damn thing about electronics...lol.

Bad joint


Fixed

[mauser]

I  must thank you all VERY much!!


Videos

https://www.youtube.com/watch?v=QQaBn3JVp3I&feature=youtu.be


https://www.youtube.com/watch?v=wvOdHOgAQ10&feature=youtu.be

[J M Fahey]

 :dbtu:   <3) 

Now you are enjoying your amp, congratulations  :dbtu:

Compare your results with those of the guy wo did not want to look inside his Yamaha amp .... and to boot blamed us for not adivinating his problem  :loco

Guess who's happy playing guitar tonight ?   8|

[DrGonz78]

Nice Job!!  :dbtu: Those loose/cracked solder joints on the filter caps can cause all sorts of strange symptoms in the amp. Shhhhhhhh.... Juan that Yamaha was a surprise "Secret" gift...

[mauser]

I have a compulsion to fix broken things.  Drives me nuts till I do. You guys gave me the confidence to do it.  This amp has a beautiful clear channel now. The chorus is awesome.  Never sounder better. The pots turn like butter.  That DeOxit stuff is a miracle worker. The pots where moderately hard to turn....now I could roll them all walking by with a pinky finger.

Next project...

Replacing two input jacks on another Fender Amp. An old Red Knob Twin Solid state.

[g1]

  If that's a red knob "the twin", it's a tube amp.
If it's a solid state twin, then it's from the late sixties and I was not aware that they had red knobs, but could have been replaced.
  If it's "the twin", you will need the special 9pin Fender jacks.  Don't even think about trying to modify to use anything else, too much switching going on in those jacks.