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Magnovox amp 175-67 with a sub amp? 7002-00

The 6BE6 tube is for FM and will not have anything to do with your issue. The only preamp tube on the receiver itself would be the 12AX7. All other tube types usually just have one filament in their center depending on the job of the tube. Also, a black spot on any tube is what's called the getter flash. Read more here:

https://en.wikipedia.org/wiki/Vacuum_tube

All the tubes on the receiver chassis except the 12AX7 tube are for the AM & FM only.

Those metal tube shells just pull off. Some you have to turn and pull but I don't think Magnavox used any of those types.

Here's another thing you can try to see if the main amplifier is working properly since you don't have a CD player. Unplug the right & left RCA jacks coming from the receiver going into the amp and just take a spare jack and plug it into those spots and touch the other end. You won't get shocked or anything like that but it will buzz loudly. Its like when you plug a guitar jack into a guitar amplifier and the other end goes to the guitar, when you touch the end going to the guitar, it creates this same buzz.
 
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Ok I'll try that wish I could find a speaker wiring diagram i have every other type of schematic for everything it's kinda neat the original conference notes and everything for mpx and amp.
 
Hey J,

My suggestion at this point is to get some wire.....3 feet of wire from Home Depot or you local hardware store....lamp cord or what ever.

Very simply connect 1 wire to that empty screw up front....and the other end to the crossover that is not the black wire.....or directly to the terminal on the Woofer that is not its black wire.

Right or Wrong...at least you'd know if the Amp is putting out a signal on that silent channel....or not.

OR....Better yet.....take that lamp cord and connect both wires up front to those 2 screws.....and then touch on both Woofer connections on the silent speaker. That will bypass the selector switch and the crossover and the molex plug in back.....for the silent side speaker.....and tell you if the amp is putting out a signal on that channel or not.
 
Unless it is the speaker switch, that pretty much narrows it down to the amp. :thumbsup:

From here on, you would pretty much have to take out the amp to really know what's going on. If we were to beat this to the ground, the only other culprit would be if you had a bad speaker output transformer. You can easily test the primary and secondary sides of the suspect speaker transformer with a DVM set on the ohms scale.

Let's check:

1) on the amp, you tried swapping the left 12AX7 with the right 12AX7 right?
2) did you swap the two left 6V6's with the two right 6V6's?
3) your touch test pretty much narrowed it down to the amp.
4) the rear molex plug should be for the speakers. The forward one should be for the speaker switch.
 
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Leland47 said:
Hey J,

My suggestion at this point is to get some wire.....3 feet of wire from Home Depot or you local hardware store....lamp cord or what ever.

Very simply connect 1 wire to that empty screw up front....and the other end to the crossover that is not the black wire.....or directly to the terminal on the Woofer that is not its black wire.

Right or Wrong...at least you'd know if the Amp is putting out a signal on that silent channel....or not.

OR....Better yet.....take that lamp cord and connect both wires up front to those 2 screws.....and then touch on both Woofer connections on the silent speaker. That will bypass the selector switch and the crossover and the molex plug in back.....for the silent side speaker.....and tell you if the amp is putting out a signal on that channel or not.
Click to expand...
I got some wire going to check that now
EDIT no change attached wire to terminal that didnt have a wire attached put to speaker that wasnt working and cross over no change
 
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J, Carefull if you try to remove the 6V6s. Where you can rock the 9 pin 12AX7 tubes back and forth a bit to pull them out....you CANNOT do that with the 6V6s. The 6V6s must be pulled straight up to avoid breaking the Bakelite center guide. Best solution for both tubes is to squirt some electrical lubricant that you can get at home depot under to tubes to loosen the pins gripping. This will avoid damaging the 6V6s...
 
Leland47 said:
J, Carefull if you try to remove the 6V6s. Where you can rock the 9 pin 12AX7 tubes back and forth a bit to pull them out....you CANNOT do that with the 6V6s. The 6V6s must be pulled straight up to avoid breaking the Bakelite center guide. Best solution for both tubes is to squirt some electrical lubricant that you can get at home depot under to tubes to loosen the pins gripping. This will avoid damaging the 6V6s...
Click to expand...
I've already had them all out ... hope I didn't break one they both still have 2 lights
EDIT misread.. which is the 6v6
 
The 6V6 tubes are the 4 big ones on the Amp. If the Bakelite guide pin gets broken....they still work...you just have to figure out how to plug them in if that happens.....
 
Leland47 said:
The 6V6 tubes are the 4 big ones on the Amp. If the Bakelite guide pin gets broken....they still work...you just have to figure out how to plug them in if that happens.....
Click to expand...
Ok ya I have had those out too guide pins still attached what do I need to do with them
 
cademan said:
Unless it is the speaker switch, that pretty much narrows it down to the amp. :thumbsup:

From here on, you would pretty much have to take out the amp to really know what's going on. If we were to beat this to the ground, the only other culprit would be if you had a bad speaker output transformer. You can easily test the primary and secondary sides of the suspect speaker transformer with a DVM set on the ohms scale.

Let's check:

1) on the amp, you tried swapping the left 12AX7 with the right 12AX7 right?
2) did you swap the two left 6V6's with the two right 6V6's?
3) your touch test pretty much narrowed it down to the amp.
4) the rear molex plug should be for the speakers. The forward one should be for the speaker switch.
Click to expand...
Yes all this has been done and no change still the left speaker works and the right is dead lol
 
Did you hook up wire to the speaker from those 2 front screws?


Edit: ok, read above that you did.

you might try hooking up 2 wires and go directly to the woofer....that would eliminate everything in between.....the selector switch...and the molex and the crossover....
 
Lol....heck, you've had it easy so far!

All those amps have to be pulled out and rebuilt with new capacitors and such to make them safe and reliable anyway.


Edit: you could pull it out, turn in upside down...and do a visual inspection for bad caps....or a burnt resistor....and find your problem that way....

The Amp is just held in by 4 bolts and the Molex plugs I think just pull out. That little 2 wire connection with the circle ....it for a pilot light. Just pry that one out.
 
Yes, I think you have to.

I'd rely on Cademan to guide you. I'm just good at a loose wire or so....not much more.

But a visual inspection is vital, at the least.
 
I took a picture of the molex connection because I'm confused 6 wires on the amp but only 3 out of the plug to switch and crossover
 

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That's correct. One (black) is ground, and the other two are for the right and left speaker positives. See a green dot on the woofers? This indicates positive. All black wires terminate at the same place which is chassis ground or center tap. The black wire is split between the two speakers negatives - .

While the amp is out, do you know how to use the ohm meter for checking the bad side output transformer?
 
I looked pretty closely at the pics.

Underneath...you have a left and right channel going to that Molex ( 1 light green and 1 white wire )with a shared Common Ground... black. It looks like you have 2 darker green wires coming from the 2 Out Put transformers.

The picture of the molex pulled out...with 3 wires. You have a shared common ground black for both channels........and a Yellow and Brown for each channel.

That all looks OK IMO.

You could trace those 3 molex black, brown and yellow wires and see where they go...
 
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