I am trying my hand at repairing a RCA 45 player with the rp190 changer. It has a new cam and idler. The problem is that when cycling it stops mid cycle. I give the platter a very slight nudge and it continues to cycle on its own.

Assuming the idler and cam were resurfaced properly and no oil/dirt is on any surface--First--You may have weak contact of the idler to the platter/drive shaft. You can check that by grabbing the platter spindle while it is running, and see how much it 'fights' you when you try to stop the platter from turning...If you only have to lightly grab it to stop the platter turning, that lack of tension may be the problem. The spring that pulls the idler wheel to the drive shaft may need a 'tweak' to increase tension, but don't go too far with that. Also, the idler wheel may not be lining up vertically flush to the drive shaft, and you lose some drive power there. You can eyeball that and bend the idler wheel gingerly to get a good surface to surface mating...Second--Assuming you don't have issues in the spindle top mechanics----You may have to adjust the bracket that sets the 'distance' the changer cam sits from the splined piece in the platter shaft (sorry I forget the part name) the cam rides on. You may not be getting enough contact there to overcome the mechanical resistance of the changer mechanics. This also sets the rest point for the cycle cam so it doesn't keep cycling...The rest spot is the area in the cycle cam that has the recess. You have to do a kind of balancing act there so the cam comes to rest without going into the reject cycle all the time.
It's hard to explain this stuff...but I've worked on tons of these players and just do it automatically when repairing. So if you're confused, keep asking stuff.

Did you do a complete tear down/clean/lubrication on the changer? If not, you are probably encountering lack of grip between the cycle cam tire and the knurled roller it engages during the change cycle. The teeth on the roller need to be totally free of any debris or oil to grip well. I recommend you remove the turntable, clean all drive surfaces (motor shaft, both idler tires, inner turntable rim, cam tire and the knurled roller) with isopropyl alcohol. Once all of those parts are absolutely clean, your changer should work fine. If not, then refer to the above comments regarding spring tension, alignment, etc.

In the condition that Robert describes, the platter would still be rotating, but the tone arm would stop somewhere through it's reject cycle. The condition that Tbirdkid describes would be the platter stopping it's rotation, and the reject cycle taking off when you help it get going again. If this is the case, which seems to best match your description so I'm guessing it is, I have found that sometimes just cleaning all the idler, motor, and platter-rim surfaces can help - sometimes a little oil finds it's way in there and that's all it takes.

It's usually necessary to replace the motor mounting grommets. They dry out and can no longer hold the motor in the correct position to drive the idler.

-David

Thanks everyone for the advice. When I have time tomorrow I will try out some of your suggestions. Will let you know the results.

Thanks to everyone I got the player cycling. The hint was being able to stop the platter easily. It wasn't the tension on the idler, but a mistake on my part. I got a bit carried away with oiling the motor and some dripped down on the idler and motor shaft. Cleaned those up and I am up and running. Thanks for your help.

Get a cat instead. At least they like cheese and cracking toast.