Magnavox Chassis #196-55 Resistor Question

[Trout]

My gal found me a couple more toys at a garage sale this past weekend.
So I thought I would take a break from my oscillator/guitar amp nightmare.
I figured these should be inspected before powering them up + changeing the power cords out.

I happened upon a componet (Power Resistor?) that looked a bit discolored.

So, When trying to see if there were any markings on the other side, I discovered a possible burn? or arcing point?
Photo

The wire under the resistor either got hot and melted the insulation or possibly there was some arcing taking place?
That or the resistor got hot and melted the wire insulation?
The wire appears to go to the remote speaker terminal.

I am guessing the resistor is just a 10 -15 watt 125 ohm?
Is there anything special about that type of resistor or can I just use a ceramic wire wound?
I have not located a schematic yet but the rest of the unit seems ok.

It has 2-12AX7's, 4-6V6GT's & a 5U4GB Rect.

Gene

[hkaplan131]

What pin does the part in question go to on the tube? Does it daisy chain to the same pin on the other tubes. I suspect it is a screen grid resistor for the output tubes. Is the other end going to chassis ground or to a supply voltage? Did you measure it with an ohm meter? Is it open now?

Howard

[Trout]

Originally posted by hkaplan131
What pin does the part in question go to on the tube? Does it daisy chain to the same pin on the other tubes. I suspect it is a screen grid resistor for the output tubes. Is the other end going to chassis ground or to a supply voltage? Did you measure it with an ohm meter? Is it open now?

Howard

It Daisy Chains to all the PIN 8's of the 6V6's at 1 end, And connects to ground on the other.

I havent removed it yet, nor gotten an ohm reading off of it. I just saw the burn mark and discoloration and figured it best to swap it out.
Gene

[tubelab.com]

Pin 8 of a 6V6 is the cathode. The part in question is the cathode bias resistor, which does get pretty warm in normal operation. My guess is that it is OK, but test it with an ohmmeter. It should be in the few hundred ohm range (125 ohm is possible). If you want to replace it you can use the ceramic wirewound resistors from a modern supplier.

[Tom Bavis]

If thats AMP196, it's in Sams # 454 - weren't you the one who had hauled home a big pile of Photofacts?

[Trout]

Originally posted by Tom Bavis
If thats AMP196, it's in Sams # 454 - weren't you the one who had hauled home a big pile of Photofacts?

Yep, Sort of, I still havent gotten back to southern Illinois to pick them up. Seems like lately every weekend we plan on going something gets in the way. I am sure I probly own the correct sams, Its just 5 hrs away


Gene

[Trout]

Sweeet,
Got it done. Resistor measured 130ohm out of chassis, I had a 10 Watt ceramic correct value.

It never ceases to amaze me how quiet these old maggies are especially as messy as they look inside. But Hey, who am I to say lol, I can mess up the simplest fender amp ever built

I dont suppose theres a way to get a bit more bass out of these without bigger iron OPT's.

No wonder it has 15 inch woofs.
Either way, the hour I spent checking it out was well invested , looks like theres alot of good years left in this one. Worth the retube easily.
Hope I get as lucky with the admiral she grabbed me also.
4-6BQ5/el84 18watter, Neato!
Gene