Consignment shop 66 Vibrolux Help! getting it running

[TerryD]

My dream amp.  Looks like a 66 Vibrolux..I think?  Jensen speakers 220611  There is a T17366 inside the amp and A06181 stamped on the back.  I just picked it up for 500 bucks.

The problem is no sound except for some nasty crackling sputtering.  I think I got some nice oscillation when I shut it off last.
White powder crap all around. I've only tried swapping a couple of tubes so far.

I have a vibrolux AA763 layout copy (Fender picture layout).  that's what I use for schematics.  I completely rebuilt  an Bassman head AB165 using Dan Torres book like 20 years ago.  I've done several recaps.

Could you please give advice how to get this up and running, maybe in logical steps and in simple terms.

Had like a 68 vibrolux 30 years ago that beat me to death and sold it.  that's why I learnt to work on amps as much as I have.  done plenty of other work just as various sites walk you through.

I hope I can get some pictures up.  Thanks ahead.  Terry
Absolutely love this amp.

[drew]

http://el34world.com/schematics.htm#Servicing%20fender%20amps

[sluckey]

It's a Vibrolux Reverb. The 10K resistors on the cap board mean it's probably model AA964. Schematic is in the library. Your AA763 schematic won't work.

[stratele52]

An amp like this one need first a complete tubes socket contacts cleaning and give more tension  . I just finish to fix an amp ( Super Twin Reverb, 1976 ) with same issue . After cleaning contacts and give  more tension it work.

Be sure all tubes are good . If not working after that , voltage reading is needed to go farther.

Filter Capacitors look good , enough to power on amp to fix it . After the amp will play nice , you may decide to replace them for more punch and power and to last long time  .


You have a great deal , congrat .

[Ed_Chambley]

Yes, it looks like an AA964 as the first 2 filter caps (the ones that have been replaced) are in series.  I really have never trusted this and I have put in series 40uf/500 Sprague.  You can measure the voltage once the amp is up and running.  Schematic states 410v for the Initial B+, but it is most likely higher due to wall voltage.  Basically what I am saying is the voltage usually exceeds the 20%.

The paper Mallory caps, I can see problems with them in blisters.  Not sure about the other side of them.  Probably will work.

I would pull all the tubes and check voltages against the schematic.  Of course they will be higher, but will give you an idea of the general health of the Power Transformer as well as circuit components. Measure across the heater and insure the proper voltage.  Clean and retention sockets as was suggested.

Usually, the blue molded caps survive well and are worth keeping.  The dual can Mallorys in the board would be suspect to me.  A lot of time these are fine, but this amp looks like it had an exploding cap in the doghouse as I do not know where else the powder came from.

Replace with known good tubes, but I would use a bulb current limiter if the Power Transformer were original.  Most likely fine, but it does not hurt to be cautious.  If this is good, then you can get operating voltages.  The amp may work at this time anyway.

This is a great find and the value of the amp exceeds greatly what you paid, especially if all the iron is original.  If you have to put a few dollars in it, you will not be throwing the money away.  I don't know the cab condition, but without seeing it I can say you have more than doubled your money if everything works and is original.

My 2¢

[stratele52]

  The dual can Mallorys in the board would be suspect to me.  
 

My 2¢

If you talk about dual 25MFD bypass caps ( on 12XX7 tube ) we can keep theses caps until the amps will sound / work . Usually fresh good quality caps will make the amp sound better . A replacement to do with filter caps for long time with no problem

[eleventeen]

The white powder is almost certainly the oxidized, galvanized coating of the chassis (zinc oxide) and is only an esthetic issue, not a functional one.

If you did a "recap" job on a Bassman, most likely, this is will be the core requirement of getting this back to working. It's exceptionally likely you'll want to replace the 100K ohm plate resistors in the preamp section....the 3 watt metal film ones Doug sells are ideal for this.

The same (humidity, typically) conditions that caused the chassis oxidation will very likely give you some problems with regard to the tube socket pins and possibly the pots (controls) Myself, I would start with the least invasive techniques and see where that gets you. Maybe you can get away with pulling out the tubes and pushing them in and out of the sockets several times with no chemical assistance. Always nice to use a known dead tube for this in case you bend some pins with fat fingers. If you want to go farther, spray each socket with a slight blast of DeOxit (and use REAL DeOxit, expensive, not just "tuner cleaner" (cheap). I prefer to avoid tweaking the metal pieces that make up the contacts....but sometimes this cannot be avoided. You have to be really, really careful with that. The pots probably need DeOxit...and ultimately, you may have to replace the 1/4" input jacks. I find when these get past a certain age/corrosion point, they are noisemakers that will not leave you alone.

That is the basic order of attack. You're just gonna have to go as far as you need to go to get it flying. At some point, you may hit some kind of self-imposed brick wall, such as having to replace the tube sockets or rewire some or all the interconnect wires from parts board to tube pins. And at such a point, it will stop being "all original except for cap job" and start to be "rebuilt" which may impact its market value.

Platefire had a thread which is very recent (so should be easily findable) where he found a basket case Pro Reverb and rescued it. http://el34world.com/Forum/index.php?topic=16446.0

His parts board was in equivalent or worse shape than yours and he got it going without too much misery. You'll probably get some add'l tips there. Keep us  posted on your progress and ask questions before you embark on some wild idea...all of this has been done before.