@mahler123
Obviously, you had a bad power supply/motor with the Rega P5 you once owned. Unless your turntable is automatic (most are not), the most common problem with any turntable is the motor.
I have owned numerous turntables from Pro-Ject, Rega, and one of my first, a Stanton. One of the things I learned is that the majority of turntables have the motor integrated into the plinth. From an engineering standpoint, it makes no sense. Motors create vibration which when buried in the plinth makes the vibration much harder to dissipate. As I moved up in Pro-Jects over time, it culminated in owning a Pro-Ject 9 Xtension. I saw it as my last TT purchase. Figured there would be no vibration in a TT costing north of $3K.
With the Pro-Ject 9 I could tap on the plinth and hear the taps in my speakers - it was a sounding board. However, it did still sound good. After a while I realized it was because of the Sumiko Songbird cartridge. I guess it was a trade-off, but when the motor died within the warranty period, it was a huge mess. A TT that weighs 35lbs of turntable is a beast to ship in for repair. After the second motor started making a noise like the first one, I sold it. I lost at least 2K. The worst purchase I made as an Audiophile.
When I got my first Rega P6 - with the separate PSU - I was taken aback at how black the background was vs. the Pro-Jects. The heavy vs. light TT debate was an obvious win for Rega. I mean, if I were to have an issue with speed, I would just get another PSU. Problem solved. Easy as pie.
Pro-Ject's owners wife started a new company called EAT. The high-end EAT turntable incorporates a separate PSU just like Rega. If there is anything wrong with Pro-Ject tables it is the motor being a part of the plinth. If anyone asks me what I think the best Pro-Ject table is I would say the EAT C Sharp!
The Rega P5 was discontinued in 2011. In your case, all you needed to do to fix the problem with it was to swap out for another PSU. Owners seem to be happy with them. Bad motors happen, inside the plinth or not. I would be remiss in not mentioning that the motor in the Pro-Ject 9 was unique (maybe proprietary) and not used in other Pro-Ject tables. Not true with Rega's. One external PSU fits all.
I am on my second P6. The first one had the Exact MM cartridge which was the best MM cartridge I had owned. But having owned MC cartridges on my Pro-Jects, I wanted an MC Cartridge which is why I got a new one with the Ania installed.
The P6 and likely the P3 Anniversary edition, is a superior TT with reference to speed stability. No longer am I looking at a long rubber band - that sometimes slips off and is a chore to put back on - on a Pro-Ject wondering how I will know when it becomes time to change it out for a new one. For all the experience I had with Pro-Ject TT's, I am a bit miffed that I kept going back considering I worked with engineers for years (I am not an engineer) but for some reason (probably because Pro-Ject does use good cartridges) I did not consider the setup to be an engineering fault. My bad; you live and you learn.