Line 6 Spider 212 with persistent hum

[mbailly]

So I'm writing for a friend who owns a Line 6 Spider 212 (100 watts).

The story goes:  He was playing guitar in his basement and was goofing around and apparently caught his guitar on an exposed (electrical) wire.  In the process of electrocuting himself, he also did some damage to the amp. 

Now the amp has the 60 cycle hum (or very equivalent sound) no matter what is plugged into it.

I would like to fix this myself, if possible, and save my friend some money.

Thanks 

[Brymus]

Sounds like it fried some caps,try to find the schematic,write to Spyder if you have to.
Taking pics of the insides of the amp might prove helpful too.
Let us know.

[J M Fahey]

Your friend should pray 8 hours a day, just for being alive.
Besides that: what was he doing close to an *exposed electrical wire* with a guitar hanging from his neck?

[mbailly]

Your friend should pray 8 hours a day, just for being alive.
Besides that: what was he doing close to an *exposed electrical wire* with a guitar hanging from his neck?

Well I'm not exactly sure why he had an exposed wire in his basement.  I'm guessing it was one of those sketchy college houses.  He lifted the guitar up in the air (imagine the guitar hero power-up) , and caught part of the headstock or maybe part of one of the tuning mechanisms.

I will get some pics up as soon as I can.

[mbailly]

I found two suspect spots.

In the second picture there is a white substance covering a few spots. 

[phatt]

The white stuff is likely just the factory goob used to support large components like Electro Caps. (in the old days they used Real Brackets).
Judging by what you have said and looking at the fried components at what looks like the input socket, Then it's all bad news.

If *Mains* Voltage has been induced into that circuit then probably a lot more than 2 resistors are fried, unless you are gods best friend I'd say most chips will also be fried.
The poweramp may still work but that would be the best you can hope for.
Now it's just *Spare parts*
Phil.

[J M Fahey]

Now it's just *Spare parts* Cry

Those surface-mounted-components, everything-into-a-big-mean-chip amps are unrepairable, even by their makers, unless the trouble is a *very* minor mechanical one, such as a scratchy pot, worn/bent jack, etc.
Even Line 6 themselves will give you a new one or at least swap the entire board if it breaks during warranty time.
It´s cheaper than paying somebody $50/65 an hour sitting at a bench trying to repair it, with uncertain results.
Not all is lost anyway  , now you have a beautiful enclosure+speaker+power supply waiting for your chipamp.
What does the transformer supply?

[monkeycabbage]

now you have a beautiful enclosure+speaker+power supply waiting for your chipamp.
What does the transformer supply?

Jm, I love your optimism!!

I'm still pondering over my Rock Pro but have considered several times of the possible salvage benefits!

[mbailly]

The white stuff is likely just the factory goob used to support large components like Electro Caps. (in the old days they used Real Brackets).
Judging by what you have said and looking at the fried components at what looks like the input socket, Then it's all bad news.

If *Mains* Voltage has been induced into that circuit then probably a lot more than 2 resistors are fried, unless you are gods best friend I'd say most chips will also be fried.
The poweramp may still work but that would be the best you can hope for.
Now it's just *Spare parts*
Phil.

The amp works perfectly, on board efx and all, save for the loud hum.  Maybe I'm a foolish optimist, but the amp seems salvagable.  (or is my friend better off buying a new head and using it with this cabinet.)

[Brymus]

Thats insane he's lucky to be alive.
You could try removing the input jack then unsoldering all the components where the board has turned color.
Use some acetone and clean it up real good so you can inspect the traces.
Find the schematic and replace those burnt SMD components(if there is enough of the traces left)
Then if it still hums IDK I would check all the electrolytics with a meter to see if thats it.
A bad filter cap can make a bad hum and they dont like the wrong polarity voltage.
Beyond that (and thats alot of work but not impossible)Yeah its probably spare parts.
So a few hours patient work for a maybe,but no outa pocket expense minus a few passive components.

[Enzo]

What has probably happened is that the ground trace from the input jack has evaporated - blown open like a fuse - from trying to handle the mains current to ground.

Even if hte rest of it works, that missing ground will cause large hum when trying to play through the amp.

Looks like some small components burnt up, could be small value resistors to ground could be low voltage caps, etc.   Line 6 doesn;t hand out schematics.   Finding one will be just luck.

[phatt]

I'm with *Enzo* :tu:
Yeah well if it still works just rebuild the input section,,, but with a lot of surface mount and double side boards you still have a long way to go.
Hope your  eyes  are good.
Phil.

[mbailly]

Thanks for all the feedback.  I'll see what I can do and let you know how it goes.  :tu:

[J M Fahey]

Enzo, good guess. At least it sounds reasonable. I use a "jeweller's loupe" to check suspect traces and pads, the kind you place on your eye and frown to keep it there. If unavailable/expensive, a pair of "+4" cheap reading glasses and a good desklamp will do nicely.

[Enzo]

And when ground traces do burn open, it isn;t always right near the rest of the problem.  They will burn open at the thinnest point, so there might be some large ground traces around the jack, but some little narrow point where it connects with other ground areas becomes the weak point and PFFFTTT.