Eganator Rebel 20 - Bench fun

[LooseChange]

For you guys who do not repair stuff... It ain't easy at times.
This is an a small amp that shorted out and 2 diodes and a cap need to be changed... See the big radial cap all the way to the right... I need the remove the circuit board, remove the parts, clean up the scorched PV board (it was bad) and replace the bad parts... Takes lots of time and a really good memory.
Notice the two levels of PC boards at the back.. Can hardly get a probe in there to measure voltages.
FUN Sunday afternoon.

[jjasilli]

From vintage Ampegs pcb's  to ultra-modern pcb's, you're a real trooper.  I'd be tempted to use the darn thing for target practice.   

[LooseChange]

It's funny... Sometimes I look at the project and think, I really don't want to get into that. But, I always dig in.  I think it's the chaallenge to get it done and make someone happy.

Gotta admit, there have been a few... "Oh sh$t" moments.

[Jack1962]

I hear ya brother , I repair ton's of amps like that , and I almost always have one or two of those  "Oh sh$t" moments   

[Greasehorse]

For you guys who do not repair stuff... It ain't easy at times.
This is an a small amp that shorted out and 2 diodes and a cap need to be changed... See the big radial cap all the way to the right... I need the remove the circuit board, remove the parts, clean up the scorched PV board (it was bad) and replace the bad parts... Takes lots of time and a really good memory.
Notice the two levels of PC boards at the back.. Can hardly get a probe in there to measure voltages.
FUN Sunday afternoon.

I need a schematic for one of these. Do you have a copy? Email me please.

[LooseChange]

No schematic.
Why do you want a schematic.. Got another broken one?

[Tone Junkie]

Greasehorse probably wants to copy one, my thoughts at least.
Bill

[John]

For you guys who do not repair stuff... It ain't easy at times.
This is an a small amp that shorted out and 2 diodes and a cap need to be changed... See the big radial cap all the way to the right... I need the remove the circuit board, remove the parts, clean up the scorched PV board (it was bad) and replace the bad parts... Takes lots of time and a really good memory.
Notice the two levels of PC boards at the back.. Can hardly get a probe in there to measure voltages.
FUN Sunday afternoon.

*shudder* Better you than me! 

I guess that's the nice thing about building; you engineer it to work on later.

[LooseChange]

That's why Leo Fender was a genius.

[RicharD]

I opened one of those up to see what makes it tick.  I just closed it right back w/o so much as a sniff.  12AX7's and 6BQ5's.... That what makes it tick.

[DummyLoad]

12AX7's and 6BQ5's.... That what makes it tick.

...and 6V6s. 

[jeff]

 "Tone First!!"

[LooseChange]

"Tone First!!"

Yeah it "says" that inside... I was not impressed.

[alerich]

I have one. I think it's a bitchin' little amp. To each his own tone, I guess.

[Platefire]

I assuming this is about a 20 watt amp. With all the circuitry I'm also assuming this little buddy has a lot of features??? I looks pretty sceary to work on!

[jeff]

 Is this the amp with the 6V6/EL84 blend knob? How is that circuit wired? I've heard a lot of conflicting theories about this and would like to know. Some say a special OT with 6V6 and EL84 taps. Does that look to be the case?

Also I've heard it said the wattage knob is really just a traditional master volume. Is this true? If not what is it?

A schematic would be appreciated if you have one. I can't find one anywhere and am very curious.

Thanks
 Jeff

[alerich]

The amp has a separate master volume control. The watts control acts like the Hall VVR in my home brew Studio 15 but it does not seem to drop the volume/voltage as much at the minimum setting. When you move the watts control there is a slight cracking - designed that way since Egnater says there is a small amount of DC on the pot. That leads me to believe it is a different circuit than a VVR although it behaves in somewhat the same fashion.

[LooseChange]

I believe the watts control varies the current in the phase inverter.  We all talked about that type of control a while ago. It makes noise because there is DC on the pot.
No way does it go from 20 watts down to 1 watt.

[phsyconoodler]

child's play. Once you've done a few Messy Boogers and TSL Marshall's those look easy.

  PCB amps don't scare me any more.Bring it on! :smileinbox:

[Platefire]

Get away from that Wheelborrow Phsyco, you don't know nutten bout Machinery!!! 

[Voxbox]

Hey Phsyco,

I was raised on pcb equipment.

After being on this forum for a while I can say that tagstrips dont scare me anymore!
 

[mresistor]

looks like a lot of Xicon caps......  so LC was the problem visually apparent when you opened it up? Also, what IYO do you think caused the failure?

[LooseChange]

looks like a lot of Xicon caps......  so LC was the problem visually apparent when you opened it up? Also, what IYO do you think caused the failure?

It was very obvious from the smell and with a bit of light you can see the scorch marks.
It appears one of the 6V6's went bad and caused the chain reaction.

Yeah, I've worked on lots of pc board amps. Mesa's, modern Marshall's, The folded circuit board Peavey's.  I brought this amp up because of all the tightly bundled wires and the massive amount of connectors in such a tiny place. All of which had to be removed to get under the board. And at the price of this amp... It's not throw away electronics when it breaks.

[Tone Junkie]

LC you must have a hell of good memory to put all that back together when your done, That looked like a nightmare.
Bill

[Greasehorse]

No schematic.
Why do you want a schematic.. Got another broken one?

No. I bought one of these on Fleabay and wanted to look. I called Egnator but they refused to send one with values on it. One guy said he saw one on a couple places but I have found none. Guess I am hard headed and want a damn schematic!...lol

They did send me four other files and a schematic with no values on it. See the attachment

[alerich]

Interesting. LC, you are correct. The watts control simply limits current through the PI. The mix control simply varies inversely the amount of signal going to each tube pair. They are both running all the time. Thanks for the print - very informative even without values.

[jojokeo]

The watts control simply limits current through the PI. The mix control simply varies inversely the amount of signal going to each tube pair. They are both running all the time.

That is interesting and good to know.

Thanks for the print - very informative even without values.

I agree, most of the time the parts board is labeled by component # so values aren't really needed unless the part you're replacing is so burnt you can't read it. But w/ a schem you can either see the companion/associated part of get a really good guesstimate by what else is there.

[scstill]

The amp has a separate master volume control. The watts control acts like the Hall VVR in my home brew Studio 15 but it does not seem to drop the volume/voltage as much at the minimum setting. When you move the watts control there is a slight cracking - designed that way since Egnater says there is a small amount of DC on the pot. That leads me to believe it is a different circuit than a VVR although it behaves in somewhat the same fashion.

Thanks for this tip I was about to post for reason why my Rebel 20 "watt pot" was crackly, Thinking something was wrong. Good to know Egnater designed it that way.

[AmberB]

It's always fun and games until you find a broken PC board...

[jojokeo]

wow, can't believe this is 10 years old