I didn’t need a new amp but I had fun resurrecting a BA115 that I wanted another project. Looking around the local classified ads, I found a B5R that sounded like a good candidate. After a few email exchanges with the seller asking about its condition, I took a chance and bought it today. Coincidentally, as soon as I take this one home, another one pops up in the classifieds in better condition for a reasonable price.
This thing has had a rough road life. I don’t think it had ever been mounted on a proper rack system or road case, therefore, it had sustained a few scratches and dents on the case. According to the seller, it had also been dropped. Six knobs are missing. Surprisingly, the knobs are plastic: they look aluminum from pictures.
Anyone know of good replacements? It’s also missing the “style” selector knob, which is a “D” style shaft.
I’ve looked into Small Bear Electronics, LS Electronics, and Full Compass. Small Bear sells aluminum knobs that look similar but haven’t found testimonies on the web about how they fit into Ampegs. LS Electronics has the original knobs but their price was too high
for this project: This is a low-budget project. Regarding the Full Compass knobs advertised as replacement knobs for SVT 6s, anyone tried those? They have two types…wondering what the difference is between the two.
One thing that the seller indicated is that some sound does come out of it. I don’t have a cabinet to hook it up to at the moment so I can’t check. But, according to him, the ¼” speaker output jacks are very unreliable and have to be wiggled or the cable has to be propped with something for sound to cleanly be put out. Also, a bass with active pickups was played through the 0db input and he thinks that might have fried some components.
Anyway, this thing is heavy.
I plugged the amp to my light bulb limiter and there is definitely a short!
The LED indicator light for the OD is always on and pressing the channel selector button doesn’t switch the LED light to clean or OD: Just stays on OD. The combine button, however, turns on the “clean” LED indicator.
I’m not really sure where to start besides opening the case and having a look at the parts and searching for obvious damages. I’ve downloaded the schematic for a B4R, which should be similar. I can’t seem to find a specific schematic for a B5R.
Any guidance will be appreciated. I’m still learning about amp repair and this project will be another learning experience. I seem to learn more by biting more than I can chew.

R