Fender Champion 30 troubleshooting help

[J M Fahey]

Reverb tanks come in different impedances, shown by some codes stamped on them.
For best results, you must match codes or at least have a very close one.
Google the Belton page where they explain it.
If you use a non matching tamk, it *may* work (poorly) or be unreliable.
I'd check the code and order a matching one.
Anyway, congratulations on your troubleshooting skills.

[joecool85]

Good to hear it is almost there.  I'm with Juan though and would replace the tank with a proper one.

[nebraskaplayer]

Gentlemen...
Perhaps I overstated the "weak"; I believe it's relative to a nice rich reverb that I remember from the classic Fender amps of my youth... the 60's.
I think I have reached what this amp is capable of (or at least how it was initially sold), I might look for a better tank, (read, better specs), if I can come up with one cheap.  With the understanding that it would only help "some".
I have read many of the posts on this site regarding reverb and if I could use a quote from Phatt...

"... but my answer was based on the high likelihood that the owner is chasing a ***MUCH MUCH MUCH better Reverb*** and unknowingly assumes that the *TANK itself* is where the mojo (Killer tank slapping) reverb comes from."

I had tested the tanks in both amps and got virtually identical resistance readings on both input and output leads.  Coincidentally both of these relatively inexpensive starter Fender starter amps were made in 1999.
I used the table I found here,  http://www.tubesandmore.com/  to estimate what that would mean for Impedance.  My tests for both tanks were 26 ohms input and 200 output static, equating to the 150, and 2250 respectively at 1khz.
Below is a pic of the "bad" tank removed from the cardboard tube, with the Fender part number and the codes show the BB in positions 2 & 3, which according to the tables in the above website I believe confirms those values.
Not sure if I understand why the absence of the "fine" wire between the two posts terminating each spring at the Green (output) end  affects the output sound so dramatically, but  doesn't affect the resistance measurement of the input or output leads?,  I need to do some more reading to understand the magnetics in play?
The amplifier I took the tank from would have a dollar value less than a new tank, but the enjoyment of the learning experience continues, so I think I'll continue to research the above, as well as if there is a method to find a wire with "solderability" that would have similar resistance characteristics of the missing "fine wire" attempting to repair the "bad" tank.  I don't see much support for that effort across the web, (even for more valuable, classic tanks) much less the cheap cardboard one, but... that's what makes it interesting.

Thanks again. 
Dave

[joecool85]

Are the numbers on the good tank similar to those on the "bad" one?  Also, if the resistance tests similar on both you're probably fine anyway.

[nebraskaplayer]

Yep... identical tanks , So I'm done with this one.

I would still like to play around with the "bad tank" and see if I can find a suitable "Fine wire" to repair as stated in the earlier post, so if anyone knows of  a product that may work I'd be interested in trying, like maybe a winding from a resistor or a magnetic bobbin or something?...

I know it's not worth the time or effort, but the education I have received from all here has made the repairs so far enjoyable.
I'll check back to this post occasionally to see if there are any ideas, and continue to view the forum on a regular basis, and I may have some excellent photos to share of what CAN go wrong on a solid state amp....
Dave

[joecool85]

Dave, try using wire from an electric guitar's pickup.

[phatt]

Hello nebraskaplayer,
Let me know if I'm off the track with this answer

But Something you said there leads me to think you might be not fully understanding the workings?

**The electrical wires go to the coil,,,not the spring ends.**

The springs are purely a mechanical function, they are NOT directly connected to the electrical circuit.

The spring movement is created by the magnetic effect induced by the electric coil.

(From what I can see) It is the coil wires that have broken away from the green and black lead block terminal.

Oh yeah those wires have a coating and no you can't solder them as is ,,, you need to scrape the varnish from the end you wish to solder,,, then it can be soldered as normal.

You mention wanting the golden reverbs from 60's era Amps. Sorry mate not much chance of that with the pathetic circuits used in those Amps.

Far better to buy a digi reverb pedal.

Anyway a pic might help,
Phil.

[phatt]

Just found another picky,, close up Reverb transducer setup.
Phil.

[nebraskaplayer]

Thanks for replies,
looks like I won't be looking for fine wire to repair original tank.

Phil..
I've read all your posts regarding  reverb; don't think you could be off track with an answer, but thanks for being polite.

Your comment about not fully understanding the workings, was right on the money as I stated in my previous post...
"Not sure if I understand why the absence of the "fine" wire between the two posts terminating each spring at the Green (output) end  affects the output sound so dramatically, but  doesn't affect the resistance measurement of the input or output leads?,  I need to do some more reading to understand the magnetics in play?"

My confusion came from the fact that the "wire" that I was looking at was either something left over from production that got stuck on the end of the spring post(s).. or perhaps a fabric thread that had somehow  (in this poor little amps previously hard life, based on all the damage I've found thus far), got wound around the two  spring posts,  and under normal magnifying glass looked like a fine wire. I'll repost that pic below and if you save it and blow it up you can see that it is actually thread not wire. (that also explains why when I tried to "tin" it with soldering iron it burned to half it's length immediately).
I could see the other remnant of it on the other post, that is why I couldn't understand why there would be a fine wire between both the spring posts.  (that appeared broken)
Now that I have completely disassembled the tank, read your posts,  and looked at these diagrams (the two below) from Tubes and Mores website.. I do now  understand the electromagnets and the wiring...

I looked at the wires from the windings on the magnets to the connectors and they are actually OK,  I did find one of connectors wasn't fully engaged... connected but not "tight"...

I am posting pics of windings to connectors (where we thought the problem might have been), thought might be of value to someone else in the future... if they have these tiny "tanks".
Cleaned it up, checked all the push connections, stuck in in amp... and now REVERB ....,  So now I need to get some double faced foam tape to mount back in cardboard tank, and then more tape to anchor to cabinet.

SO both amps will have working tanks in them... I might play around and make a metal tank cover, and rivet tank to it (I have some light gauge aluminum sheet stock), and see if it makes any difference.

Regarding wanting the golden reverbs from 60's era Amps...
 
I guess I'm getting a little greedy for a $20 1999 SS amp... and with all the free help here, only $4.50 in parts,  It is a nice little practice amp. 

Now to find the two D shaft knobs and I'll be set...

I do have a SuperChamp XD that can produce a fairly nice reverb blackface sound ...the amp, not me...lol.

I have "looked" at this pedal, Boss FRV-1 '63 Fender Reverb, excellent review, but I haven't played through one.  But for the little I play (so far) hard to justify.

Thanks again
Dave