cjtmacclassic
Well-known member
Hey everyone,
I picked up a 512k-upgraded 128k last weekend, and I've just finished recapping everything. That part went just fine, but now that I'm ready to fine tune everything, I found the variable inductor at L2 has no plastic core or ferrite tuning slug whatsoever. While my very brief pre-repair testing found the width was severely exaggerated, I attributed it to aging caps at the time.
From the (somewhat old) threads I've found here on the topic, finding slugs is comparatively easier than the corresponding tube. Am I correct that it is internally a 1/4-28 thread?
I have access to machine tools and reasonable engineering plastics and I'd like to try machining a replacement. If anyone has an intact tube and can measure its features with calipers, I'd really like to try this. Otherwise, I can just eyeball it and go from there. Surely the tube doesn't need to be much larger than the major diameter of a 1/4-28, with about a ~1" length from what I gather. While I haven't yet found a suitable ferrite slug, getting this out of the way is a step in the right direction.
I picked up a 512k-upgraded 128k last weekend, and I've just finished recapping everything. That part went just fine, but now that I'm ready to fine tune everything, I found the variable inductor at L2 has no plastic core or ferrite tuning slug whatsoever. While my very brief pre-repair testing found the width was severely exaggerated, I attributed it to aging caps at the time.
From the (somewhat old) threads I've found here on the topic, finding slugs is comparatively easier than the corresponding tube. Am I correct that it is internally a 1/4-28 thread?
I have access to machine tools and reasonable engineering plastics and I'd like to try machining a replacement. If anyone has an intact tube and can measure its features with calipers, I'd really like to try this. Otherwise, I can just eyeball it and go from there. Surely the tube doesn't need to be much larger than the major diameter of a 1/4-28, with about a ~1" length from what I gather. While I haven't yet found a suitable ferrite slug, getting this out of the way is a step in the right direction.
