I don't know that the speakers in the amp are "based" upon anything.  Well, other than generic "guitar speaker."  I suspect they have relatively high efficiancy to make the little amp sound louder without having to make the circuit beefier.

Sorry.  yes, the amps are certainly repairable to an individual.  I mention this only to point out that there are not going to be ANY premium parts in the amp.  Fender considers them disposable.  I don;t know what they do with them, all I know is the call tag for the dud sends it to Canada.  I am in Michigan which is very close to Ontario, so someone in Texas could conceivably send them elsewhere.    I seem to recall someone buying dead amp electronics by the pallet, possibly from fender, but I don;t know.  I have no interest in obtaining bulk blown stuff to fix and resell.  it might pay off for someone motivated.

The economics is simple, it costs Fender less to replace the amp than to pay me to fix it.

You are right, you did, I am sorry.  I lost my focus there.  Winter blues...

Keep in mind this is an FM212R, a Fender entry level product.  it is on the do not repair list.  It is very doubtful any parts in it are not from China.   If Eminence has a Chinese plant supplying the Fender plant, so be it, but until I see as 67 on the speaker, I won;t believe it.

I for one did not mention capacitors, I am more expecting an op amp skewed over to one rail.

My first thought is that somewhere in your preamp you have a serious DC offset, and you hear the sound come through as the system comes up to voltage and stabilizes.

Connect the amp to other speakers, the vibration from the inner speakers is probably vibrating a loose connection.

And likewise, turn the reverb down and the amp running, ball up your fist and whack the top of the amp. Does that make a pop or noise?  The amp should not react to the whacking, if it does, something inside is loose.

Looke connections inside are likely on larger parts like the large 5 and 10 watt power resistors, large filter caps, etc.

I thought we had already posted this, sorry, here is the CR112

Post whatever you want on this amp, Crate won;t care.

The only thing wrong with that inductor is that you think it is ugly.  It IS ugly, but they all look like that.  And as teemu suggests, if it were open - broke off at one end - then that 22 ohm resistor next to it woud likely be burnt.

If your big filter caps were all tired and dried out, the amp would hum, not squeal at high pitch.

If you turn the amp controls all to zero, the noise goes away?  Then the power amp is fine.

Does it make the noise even with nothing plugged into the input?  If so, the amp is oscillating somewhere.  But if you have to have something plugged in, we suspect the input jacks.   What if you plug a guitar into the input, but turn the guitar volume control to zero.  Still noise?  or does that also kill the noise?

So you have a PV Musician 400 series.  Peavey will send you any schematics you ask for - customerservice@peavey.com

BigBoy, may I point out that just now I checked, and the forum is being read by 8 members and 103 "guests."   That ratio is common.  Do you realize that forums like this are regularly scanned by robot visitors for places like google and yahoo?   When you google a topic and find a post in some forum like this one, it is because of exactly that sort of visitation.  So when you see 500 views on your post, the vast majority of them were not members at all.   SO don;t be thinking it is like a bunch of us sitting here refusing to respond.


it is like asking strangers on the street for directions, you can hardly count the folks riding by on the bus for not responding.

And sometimes members read the post and move on, having nothing worthwhile to add.



I make an effort to help as many people as I can over here, maybe not very many, but I do resent it if someone thinks I or we are obligated to solve all problems.  "You are not helping me enough," is not a very warm message to be sent.  I suspect others feel similarly.  This is not a simple "my amp broke" repair.  You have parts missing, and are now trying to install parts other than those the circuit expects, and when that doesn;t work, you want re-design service from the group.

My good faith help:  If it draws excess current with the different transistors, reduce the bias differential between opposing bases.  TR9 is the bias transistor, so make it turn on harder.  Does the bias adjust RV1 in fact turn the current draw up and down?  And so it is just a matter of range?  Or was TR9 or the resistors around it damaged when whatever esle went on it the past damaged the rest of the amp? Raising R34 should increase conduction of TR9.

All TO3 bipolar transistors have the same pinout.   

All bipolar TO220, TO218, and TO247 transistors have the same pinout - ECB across the front.

Point of information:

A varistor is a transient suppressor and would not be in series with the mains, it would be across them.

What you are thinking of is a thermistor, an resistor that drops in resistance as it gets warmer.  Those ARE wired in sereis with the mains to reduce inrush current.

ANd this little amp has neither, as pointed out above, that is just a cap.


And on the amp,

WHich black wire is the main?  The one that came up your power cord.  The "mains" is another term for the power in your walls - what you get from the wall outlet.

The green wire from the power cord should be screwed directly to the metal chassis - the primary chassis, not some little sub-panel or extra hunk of metal.  Screw it to whatever the power transformer is bolted to.   Not having the green wire connected represents a possible shock hazzard, but it is not going to make the amp blow fuses.

But since ther are two, one per speaker, I am not quick to decide both have the same distortion problem at the same time.  I worry about some common element like power or maybe an op amp upstream.

A cap might help, might not.  As Juan said, it really is not a problem.  Many many amps pop, and it hurts nothing.  It is not a sign of impending amp failure.

The momentary spike when the switch opens is being picked up by the preamp, and amplified by the circuit as the powr fades away