New to forum and Vinyl

A system can only be as good as its weakest link. Right now, you have a vintage system and I am going to assume that all is working at original factory spec.

So if your looking to upgrade, sorry but your recently acquired turntable should be the first to go. It was an extremely entry level TT that retailed at 140 bucks, has no adjustable tonearm and was designed with a simple P mount cartridge system. These TT’s were produced as the vinyl era was coming to a close with the advent of CD’s and were a low cost way to play whatever LP’s people still had lying around. Who knew that folks would rediscover vinyl.

I would get a proper TT - one that has a fully adjustable tonearm and that would accept standard 1/2" cartridges. Of which there a whole lot more to choose from than P-Mounts. If you want to stay with vintage, than look at the mid-late 70’s as TT’s were on the way out in the 80’s. But buying vintage has its pitfalls because the vast majority will need servicing. And if your not comfortable doing it yourself and have to take it to a shop, then you have exceeded its value. Like your current SL-BD10.

If your not comfortable repairing vintage yourself then consider any of the new entry level TT’s from Pro-ject or Rega or the new U-Turn Orbit. Good luck to you.

I agree with reubent and would stay away from the AT LP120USB. I have read more than one account that bypassing the built-in phono stage results in unacceptable noise levels. Many owners are removing it altogether. This is but one of a bunch of problems with this TT. I have read accounts of loose tonearm bearings, high w&f, and actually seen one where the black paint was flaking off the platter strobe dots. Never seen this on a Technics.

Suggestions on a TT/cartridge/needle in that price range would be great. I really like the manual turntables

Since you said you are comfortable bringing a vintage TT up to speed yourself, you are wise to consider a manual TT only. Far less to go wrong as there are no automatics and inevitable degreasing to deal with.
Consider a good used Technics SL-1500 or SL-1800, servo controlled direct drive TT. They are very easy to work on and are strictly manuals. About the most they would need to a good deoxidizing of the speed pots and possibly refilling of damping fluid for the cueing control. Plenty of online videos and instructions showing you how. They have fully adjustable tonearms, anti-skate and removable headshells. You should find these units on your local Craigslist for around $150 but they will still require the above despite what the seller says, And you can't go wrong with a good SL-1200 MKII or its later incarnations.  There are many out there that just seen home use so try and avoid one that was used for DJ'ing.  If you see an Ortofon Concorde or cheap Shure at the end of its tonearm, run from it.  It was probably a DJ table.

Speaking of Craigslist, I strongly recommend buying vintage on CL only as you will be able to inspect the TT and possibly audition it too. You can’t do this on Ebay and most selling over there have no idea what they have nor are they able to properly package it and ship it.

There are many manuals built by Pioneer, Kenwood and Marantz from that era too. Find a good Micro Seiki from the late 70’s like a DD35 or DD40 and you have found what was considered high end back in the day.

Whatever you buy, don’t put stock in the cartridge as that is pushing 40 years old and should be replaced or at the very least, stylus replaced. So I would worry about the cartridge after you have found a good quality TT.