Twangy,
If your 1229 is running well, it shouldn't matter to you that someone else's isn't. The repair tech you went to is entitled to their opinion, but doesn't seem to be well up on his HiFi history or core competencies. The 1229 is a TOTL early 70s Dual and has a heavy idler driven die-cast aluminum platter, sprung motorboard suspension, low friction, low mass tonearm, and is very capable of providing a good vinyl playback experience. Among current cartridges, I would go with an Ortofon 2M Blue or Audio Technica VM30EN, both nude ellipticals around $200.00.
Or...if your Shure V-15 only needs a stylus, get one from Jico, a VN35E Nude...https://www.jico-stylus.com/product/vn-35e-nude/