The picture was in post #4, I had to open it in a new window and then download it before I could see it.
It is the resistor standing up near the front panel, it is circled in blue.
I think it is 1k5 5 watt, it is marked "1k5 ohms 5% CW5"
He has re-posted the picture in post #8
I think the small square blue thing behind it is the relay for the  channel switching.

There is a chance that with the resistor standing up like that the solder could develop cracks and cause a bad contact just from the vibrations from the speaker also.

The link I posted in post #8 shows a much smaller component so I wonder if that big resistor is not original, it makes no sense to mount a large resistor standing up like that. Too much weight relying on the solder to support it, it's bound to suffer from mechanical failures with time.
Plus the schematic says 1 watt and that looks like a 5 watt resistor to me.

If you use a torch to light up under the PCB you can sometimes see the copper tracks from the top, see what it connects to.
The link in post #8 shows a partial picture of the tracks as well.

Cheers
Mick

Here are some pics of my RG50-112 guts for errbody.

Quote from: Tassieviking on November 24, 2023, 01:53:47 AMIf I have the facts right, the following happens:
1.Distortion channel stops working but amplifier still works but only on the normal channel.
2. When this happens both the normal and distortion LED's go out.

When you want to use the distortion channel you have to pull the Treble knob out, or use the foot switch.
The relay operates and switches the amp to the distortion channel, the relay determines the channel that is used.
power is lost to both the LED's and the relay when fault appears, pointing to the 1k5 1w resistor to me.

I would suspect that the power to the relay goes out, possibly a bad solder joint or a faulty 1k5 1W resistor that goes to the relay from the +58v rail.

It is strange that you are worried about that power resistor that is also 1k5 that is dropping all that powder, there are only 2x 1k5 resistors on that schematic that I can see and they should be 1 watt.

In a previous post the same component was questioned.
https://www.ssguitar.com/index.php?topic=4596.msg36810#msg36810

I think you should try to trace where the 1k5 resistor is that feeds the relay, and then replace it. also re-flow all the solder joints in that part of the circuit.

If you take the PCB out and take some photos of the bottom tracks and the top of the PCB we might be able to help you trace it better.
Inspect the solder joints with a jewelers loupe or strong magnifying glass and you might see the problem.
I have 3 jewelers loupes I use for that job, 10x, 20x, 30x magnification I got from E-bay for dirt cheap. Best buy I ever did.

Edit: I think the red and green LED might be swapped around in the schematic as well.
Cheers
Mick

Tassieviking,

That explanation is kind of it in a nutshell. I will pull the PCB out and look at the hidden top side of the board to see if there are any bad cold solder joints; crossing my fingers that re-soldering any possible bad solder joints does the trick. If not I'll try to go further to trace the bad component.

The sand resistor that dropped powder is a RGA 1.5k ohm 5% CW5 which stands on one end located toward the front of the amp near the master volume control. Again thanks for the help.

Quote from: Tassieviking on November 24, 2023, 01:53:47 AMIt is strange that you are worried about that power resistor that is also 1k5 that is dropping all that powder, there are only 2x 1k5 resistors on that schematic that I can see and they should be 1 watt.

I may have missed it, but I don't think he mentioned a value for the cement resistor?
There are several 7 watt resistors in the circuit and I assumed he was speaking of one of those.

If I have the facts right, the following happens:
1.Distortion channel stops working but amplifier still works but only on the normal channel.
2. When this happens both the normal and distortion LED's go out.

When you want to use the distortion channel you have to pull the Treble knob out, or use the foot switch.
The relay operates and switches the amp to the distortion channel, the relay determines the channel that is used.
power is lost to both the LED's and the relay when fault appears, pointing to the 1k5 1w resistor to me.

I would suspect that the power to the relay goes out, possibly a bad solder joint or a faulty 1k5 1W resistor that goes to the relay from the +58v rail.

It is strange that you are worried about that power resistor that is also 1k5 that is dropping all that powder, there are only 2x 1k5 resistors on that schematic that I can see and they should be 1 watt.

In a previous post the same component was questioned.
https://www.ssguitar.com/index.php?topic=4596.msg36810#msg36810

I think you should try to trace where the 1k5 resistor is that feeds the relay, and then replace it. also re-flow all the solder joints in that part of the circuit.

If you take the PCB out and take some photos of the bottom tracks and the top of the PCB we might be able to help you trace it better.
Inspect the solder joints with a jewelers loupe or strong magnifying glass and you might see the problem.
I have 3 jewelers loupes I use for that job, 10x, 20x, 30x magnification I got from E-bay for dirt cheap. Best buy I ever did.

Edit: I think the red and green LED might be swapped around in the schematic as well.
Cheers
Mick

Hi G1,

Ah okay. Thank you for correcting me. I just couldn't find RL 1 on the SS schematic, because I was looking at the wrong schematic, though I did find it on the TC schematic. My fault. Showing my noobies. I'll take a look again at the proper RG50-112 schematic. Thanks for zeroing in on it for me above.

No, he is talking about the SS version.
Look how the footswitch jack connects to a point marked 'X'.
That X goes to the relay he mentioned.

Hi Phil,

Thanks for the tips. I think you are referring to the RG50TC schematic, the RG50-112 that I have is SS and was built in 1990. It has a 1/4" jack for the footswitch instead of the old style 6 prong one my RG100ES has. Not sure what changed between the SS to the tube version.

Hi LB, and welcome, 
If the Channel led indicators are not working then the issue may well be in the switching circuit, (RL1 at top of drawing)
The relay contacts maybe faulty or power not going to B (the 1k5 1W resistor)..
 Should be over 50VDC at B. Then at the relay should be 12VDC controlled by the 12V Zener.
Oh and your sand box resistors are fine, that is just the filler crumbling nothing to worry about.
HTH, Phil.

Hi LBeast
go to preview post and try to do it from there
(I didnt figure this out somebody else did possibly G1)

good luck with your amp and welcome to the forum