Randall RG100 Classic info?

[TolerBear]

I see Orange in the resistor colors but I can't tell the others. Lol.

[TolerBear]

Did you see the other pictures I put on here. I accidentally created a new topic and there's a couple under that one.

[J M Fahey]

I'm asking because in the SS Marshall thread a few days ago exactly the same happened.

It was a 220 ohms resistor, which normally had some 26V on one end (one main rail) and 15V on the other.

Normal dissipation was (26-15)^2/220=0.55W , well within its 1 W rating, but with the shorted diode it was 26^2/220=3W .
Of course it toasted, and I suspect something similar here.

That's why instead of guessing or replacing parts at random, I always INSIST on "measuring, the shortest path to success"

Gee, I think I should patent that phrase .... only that Enzo beat me to that long ago   .

[TolerBear]

Lol. I'll try that. I guess you measure it just like a regular diode?

[TolerBear]

It did have a 1w resistor in it too. I hope I can read it. I'm gonna have to research it to see about zener diodes.

[TolerBear]

Ok I checked the zener. It checks out fine. Do you have any idea what the color bands are on the original resistor in this picture down below? I can't tell but I think it's Orange, but the other 2 I'm not sure of. The tolerance band looks silver to me.

[TolerBear]

Another try at a pic.

[TolerBear]

Another try at a pic.

https://plus.google.com/103513281531958273078/posts/1Y2kt7kGn57

[TolerBear]

Yay! I think it worked!  :tu: 8| :duh. Lol.

[TolerBear]

http://spaceryerson.com/pics/RG80-Schematic-1.jpg

This is pretty close to mine but it's lacking information. 

[J M Fahey]

Here´s an earlier version.
Basically the same as the one you posted, but somewhat simpler.
As: no +24V regulator IC, just a simple resistor+zener, one less gain stage .
But should be close enough.

[TolerBear]

Thanks. I'm about at my wits end on this thing. Lol. Maybe this is close.

[TolerBear]

Did you see the pictures I posted a link to? I couldn't figure out how to post them all on here so I posted the link.

[g1]

  Yes, the link from reply #37 is working and there are pics there.  Click on the main pic and it sends you to the rest.

Are any of them showing the original discolored resistor you are trying to figure out the value of?

[TolerBear]

Yeah I put it in an earlier post. Here it is. 20140606_124514[1].jpg