DC TT supply, need schematic with some restrictions

[Giaime]

Hello everybody!

This can be probably my first post on the "Analogue" section...

So I acquired a Thorens TD-190. It hasn't the DC adaptor and it needs 12VDC fine trimmerable to work.

Here's the question: I'd like to build a regulable DC power supply in an existing 13.8V CB supply.

The existing supply has a big 18-0-18V transformer, and a regulator board which employs an heavy heatsinked 2N3055. Max current is 3A.

The problem is that the board itself has a trimmer to regulate voltage, but its range it's not good, it goes from 13 to 16V, and on the extreme end (13V side) it goes istantly up to 19V (I guess it loses its regulation?). So:

1) can I modify the existing supply to get fine trimmerable 12V? Let's say probably from 11 to 13V.

2) should I rebuild it from scratch? I can rebuild the board only letting all the rest the same, and I'd like to find a schematic which employs the already-there 2N3055 (or another T03 transistor). Or do I get better results from building a standard "application note" LM317 regulator?

Please help! Also some general advices on the Thorens 190 is welcome. I noticed that the grease which help the platter to spin was very old and dry, so I cleaned it all and carefully replaced it with 2T motor oil.

[Giaime]

No replies so far... I've made a simple LM317 regulator in that CB power supply case and I'm happy with it