Back To The Future, Toward The Past: EAGLE 515

[357]

I got the beast today VIA USPS.

This thing is MINT!

I'll post a few pics, I will be thoroughly cleaning and touching up solder and will try to complete today.
Caps look good, no "zits".

Tubes are like JEWELS, these are some mint tubes.

I will be needing ANY info on how to maintain and care for this amp, please.

Anything that needs to be said can be PMed if you want to stay confidential.....

anything like the mods, any way to make the coils more efficient, etc would be GREATLY appreciated.

I will keep this amp like a nest of baby eagles that need a home, I am very proud to have such a item from a bygone era, and from the place that made it all happen, USA!!

:blush:

I'm loving this amp right now.

Any imperfections on the tube picures is glare I opened 1 tube bubble wrap so far.

 

[357]

Well I did a quick test run, 200W swinging about 450w.
I noticed a cap with a lump on the side, the 4th picture shows it, the 2nd cap down, but I tested it and it seems to still function for now.
I will replace all the caps in a month or so, I'm all tapped out right now.
No hum, and clean power, I didn't squawk my computer speakers like my Palomar 150A mobile amp did, not a peep.
I did buy a ground "plate" and some home ground wire, big thick stranded and grounded my gear so i'm sure that will help. Ground rods are now obsolete and not up to "code" anymore.

The tubes really lit up when I first power it up, I thought something burnt up but I guess 120V does that.
I see the drivers are brighter than the finals also.

I'm gonna set up everything and make a video.....:wub:

 

[MisterFatty]

The Bulging cap is a sure sign of impending doom... Do yourself a favor DON'T use it until you replace the caps. They are getting old and the bulge hints at imminent failure. If they fail it could cause severe and costly damage.

The normal warning of making sure to remove power, discharge caps, and common care when working around High Voltage applies.

Nice find though, especially if the glass is all good...

 

[357]

I let it sit on standby for a few hours and now it's getting 600 swing and i could excite it with more watts from 3-6 and it shows 100W for each 1W, but like you say the caps are not dependable.

I think the buldgers are the LOW suppy on the bottom of the amp, but the top ones are probaly going too.
I notice it keys at 300 then drops to 225 so the charge is not holding on the caps.
I will have to take it easy for now and start tracking down parts.

YouTube - Kenrich Eagle 515

 

[Slam Dunk]

WHOA, I Think You Have A Problem!

Maybe it just the lighting and / or the fact that you have a fan blowing on that first stage; those first 2 tubes look like they are on fire.

The first two tubes should run the same color as the final tubes.

Something looks wrong from here. Those first 2 tubes should be 20 LF6's, are they? You might have bias problems on that first stage.

.

 

[357]

Yes i looked on the schematic and the 2 drivers are fed by the transformer and the 5 finals are strung to 120V.
The 2 drivers are brighter than the rest and I notice the tubes light up like a light when I first power up the amp, they are almost white bright they quickly fade to the lower orange glow.

What would this be?

 

[357]

 

[Slam Dunk]

Yes i looked on the schematic and the 2 drivers are fed by the transformer and the 5 finals are strung to 120V.
The 2 drivers are brighter than the rest and I notice the tubes light up like a light when I first power up the amp, they are almost white bright they quickly fade to the lower orange glow.

What would this be?

There is a seperate winding for V1 and V2 on the power transformer, it is a center-tapped 40 Volt AC winding. The driver tubes are wired in parallel, pins 1 and 12 are the filament connection and should have 20 volts on them.

The RF input is supplied to the Cathode (Pin 2).

Pins 5 and 9 are the Control Grid and there should be a negative 15 volts on this grid.

Pins 3 and 11 are the screen grid and should have positive 15 volts on them.

Pins 4 and 10 are the supressor grid and is at ground potential.

You have what appears to be a "Stock" amplifier; I modified them by adding a pre-driver tube (12JB6) and a variable negative going PS to reduce the carrier and add swing to the signal.

When working properly, you can drive those first 2 tubes with as much as 10 watts DK + audio and not hurt anything.

Expect to see swing to 1000 + watts when working properly.

.

 

[Slam Dunk]

That Diode (in the lower right hand corner) that you marked with a question mark is installed backwards. Instead of having negative volts on your control grids, those tubes are cooking with plus volts.

Reverse the diode and check the 300 uf capacitor (C5) in the low voltage circuit (maybe that red wire that is going "North" that is also connected to pin 3 of the driver tubes.
.

 

[357]

that diode is backwards??
wtf?
So reverse that diode? Looks like its been that way from the factory.

 

[Slam Dunk]

Right, that is pin 3 (not pin 5) so it should have plus volts on it.

Read the voltage on pin 5 to see if you have any bias volts on your tubes, it will be in the 15 to 20 volt negative range (put your plus probe on ground and your black probe on pin 5).

.

 

[loosecannon]

remember 357,

those tubes are THE most expensive part of your amplifier.
they are worth more than the rest of the amp.

do whatever you can to avoid blowing a tube while you are getting to know this amp.

also, some tests can be done with the tubes removed from the chassis.
this might be a good thing to do.
LC

 

[357]

how tough are the tubes?
I hear tinkles comming from the when hot/cooling.
Can they take a drop?
Some pins were bent some when the box came in the mail.


the diode is ok then?

 

[357]

OMFG!!

I just noticed the

don't

on

please dont drop

would have been covered with the duty slip.
If some idiot dropped that beacse it said please drop, I'm goona puke.

 

[357]

OK here's the scoop, when I first power it up, the drivers and the 2 top finals get BRIGHT then down to a glow.
If I shut down and wait a few seconds, then power it on, the tubes light up slow from 0 to glowing.

http://www.youtube.com/watch?v=C6Gcc6owhs8