SS Rage 158 Volume Pot

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schnitzelhaus
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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Tue Sep 27, 2022 1:42 am

Sorry dak, I should've followed better.

It behaves just as Pappy says it should- the Clean volume pot does not affect the Lead channel (or the Clean channel, which of course is the problem), and the Pre and Post pots don't affect the Clean channel.

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Pappy B
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Re: SS Rage 158 Volume Pot

Post by Pappy B » Fri Sep 30, 2022 11:15 am

Finally got a chance to look at the schematic again. Have you checked capacitor C13 to see if it is shorted? It is right next to the channel switch, It looks like a resistor with a green body but it is really a cap. If you don't have a multimeter you can just lift one leg out of the board and see if that gives you volume control again.
The more I learn the more I realize how much I don't know.

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Fri Sep 30, 2022 4:53 pm

Pappy B wrote:
Fri Sep 30, 2022 11:15 am
checked capacitor C13 to see if it is shorted?
Thanks for checking on this, Pappy. I put the 1M log pot back in, and lifted one leg of C13. Pretty much the same story- Vol pot still doesn't do anything, but now, instead of being at full volume, it's at about 0.5. Does that tell us anything?
When I got started with this amp, it was fine except for a volume pot that was scratchy and cut out occasionally, and which wasn't cleared up with DeoxIT. That makes it seem to me that the problem must be directly related to something I did or didn't do.
Thanks again.

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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Fri Sep 30, 2022 5:50 pm

I see essentially three failure modes: wiper and upper tap of the pot are shorted (via a broken C13 or a solder bridge), the lower tap is not properly grounded (cold solder joint?) or the track of the pot is broken. The first and third problem should have the volume drop out when the pot is set as far to zero as it will go. I don't really see a lot of other possibilities (namely other causes would require multiple faults) for the situation you describe.

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Pappy B
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Re: SS Rage 158 Volume Pot

Post by Pappy B » Fri Sep 30, 2022 8:01 pm

Like DAK said, I think something is not right with the pot.

I have bought pots 3 or 4 times in the last couple of years and twice I have gotten one that didn't work right when I received them. In both cases the wiper contacts were not not touching the track. I fixed both of them but I always wonder when the will crap out again. I always buy at least one more than I need when I order pots now.
The more I learn the more I realize how much I don't know.

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Fri Sep 30, 2022 8:06 pm

Thanks dak and Pappy, I'll look into these possibilities and report back.
I did try a second 1M pot after I had trouble with the first, but they were from the same package, so I guess could be a bad batch (they were Amazon cheapies).
I'll look at option #2 first, since it addresses user error, since the thing was mostly working before I started mucking about.

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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Sat Oct 01, 2022 4:40 am

Stupid question: what's your soldering setup? One can burn pot tracks. Essentially you want a temperature-controlled soldering iron with sufficient wattage in order to make for quick non-lethal soldering.

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Sat Oct 01, 2022 4:09 pm

dak wrote:
Sat Oct 01, 2022 4:40 am
Stupid question: what's your soldering setup?
Not stupid at all.
I'm using a Miniware TS100https://www.miniware.com.cn/product/ts1 ... g-station/. It's adjustable in ten degree increments. I'm using it between 300-340, as needed.

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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Sat Oct 01, 2022 7:11 pm

Ok, nothing that would be asking to go wrong. Worth a thought. I seem to remember that I managed frying a pot in the past...

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Sun Oct 02, 2022 11:39 pm

Thanks, dak. I'm not saying that I couldn't possibly have fried a pot, but given the iron I'm using, and also that I've tried two different ones (three if we count the 10k pot), I don't think it's the most likely culprit.

I redid my solder joints. No change. I've attached pics, and am open to criticism of my soldering job. I reattached C13 to bring the volume back up- otherwise, no change.
I've also attached some pictures of the pots I bought. Could they be in some way insufficient for the job?
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IMG_5328.JPEG
IMG_5328.JPEG (987.93 KiB) Viewed 2782 times
IMG_5327.JPEG
IMG_5327.JPEG (1004.88 KiB) Viewed 2782 times

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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Mon Oct 03, 2022 9:44 am

Well, the solder points look quite messy and I also see some scratches. I'd use a multimeter for checking that connections are where they belong and no shorts between neighboring traces/joints are there.

Essentially checking for the integrity of the setup. A multimeter should allow you to check the ohmic parts of the layout: I doubt that capacitors (other than possible shorts) or transistors are involved with your problem.

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Mon Oct 03, 2022 9:39 pm

Thanks, dak. Yeah, it's not my finest job. :? I tested continuity from the pot to the forward leg of the first resistor in each path. Pic attached to show the points). None of them registered resistance of more than 0.5. Is there something else I should measure?
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IMG_5336.jpeg
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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Tue Oct 04, 2022 7:04 am

Well, requoting from above:
dak wrote:
Fri Sep 30, 2022 5:50 pm
I see essentially three failure modes: wiper and upper tap of the pot are shorted (via a broken C13 or a solder bridge), the lower tap is not properly grounded (cold solder joint?) or the track of the pot is broken. The first and third problem should have the volume drop out when the pot is set as far to zero as it will go. I don't really see a lot of other possibilities (namely other causes would require multiple faults) for the situation you describe.
Obviously you should check continuity of adjacent tracks where they shouldn't be connected, you should check whether adjacent contact points on your pot are connected when it is in the middle (then they shouldn't) or when it's at min or max (in which case the wiper should be in contact with the respectively correct side of the pot).

Basically you check whether the circuit resistances actually correspond to what you'd expect from the schematics, at differing positions of the wiper.

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Re: SS Rage 158 Volume Pot

Post by schnitzelhaus » Thu Oct 06, 2022 12:23 am

dak wrote:
Tue Oct 04, 2022 7:04 am
check whether adjacent contact points on your pot are connected when it is in the middle (then they shouldn't) or when it's at min or max (in which case the wiper should be in contact with the respectively correct side of the pot).
Thanks for the clarifications, dak. I tested the continuity between everything that I circled in that picture, across all of the colors (every point to every other point). I didn’t get continuity anywhere that I wasn’t supposed to.
Through testing the pot as you instructed, I discovered that I did not have the leads connected correctly. On the original pot, the leftmost lead was the ground, so I hooked it up that way. I swapped the leads around, but the problem is still the same. The amp puts out what I assume is full volume on the clean channel, and the pot has no effect. I did reconnect C13 before I did all of this. Should I disconnect it again?
I did test the pot as you instructed after I connected it, to make sure that I didn’t fry it. It tested fine.

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dak
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Re: SS Rage 158 Volume Pot

Post by dak » Thu Oct 06, 2022 8:55 am

Well, swapping wiper and upper end of the pot would have about the effect you talk about.

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