Hi Folks,
GTC kindly provided the schematics for the HMV D33A I'm working in. I need to know if anyone can help with the turntable that's installed. It's a 78rpm only rim drive turntable with a synchronous motor. There are 2 large caps installed between the mains and motor. I'm not sure what value they would be or what they do (I'm guessing some sort of start caps) I need to replace them but need help in identifying them.
Thx scott

It might be an idea to see if the cap is across the mains, or one has a separate wire feeding into a different point in the motor?

Perhaps a photo? Second even that it may be a leaky paper type a capacitor meter may give an idea? On end needs to be out of circuit to test.

There are motor wise start caps & run caps & they are different. See if there is a plate on the motor with voltage etc.

Marc

Those old motor caps often contain carcinogenic substances so use due care, hand washing etc.

Thanks guys, I'll post a couple of pics

Hi again,

I have emailed Brad 4 pics to load. The pics show the 2 caps (caps are the size of D size batteries) the motor has no voltages printed on it. The caps wiring is not exposed but are housed in a Bakelite housing that has the mains wired to one side and three taps going to the motor itself. I'm guessing the caps are start and run caps. The motor runs but runs slow and when the tone arm is placed in the record the motor slows down. I'm assuming the caps are probably the problem as the motor itself seems fine.

Thanks in advance

Scott

Have you lubed the motor bearings and filed down the surface of the rubber wheel (using the motor to turn it) so that the surface glaze is removed?

Clean motor pulley and rubber wheel with metho.

Hi Ian, yes al the above has been done. The motor was originally seized and is fine now. It's definitely an issue when the motor is under load. I suspect it is the caps but it's hard to read their values given the age of them.... they look like 1.1mf but hopefully someone here will know and I'll replace them.
Cheers

Most early turntable motors similar to the early Garrard, have what is called a floating self lubricating bearing that works on the same principle as a ball joint.
This allows the bearing to float from left to right until it finds the center.
These bearings , although they were originally designed to be self lubricanted have usually stopped floating and cant find the center anymore.
By removing the bottom bearing cap you will see how the bearing floats on an egg shape eye ball.
3 drops of oil on the eye ball to ensure it is finding the center.
You mentioned the motor was seized????
Oil on the bearing will allow the motor to turn freely, ,
But oil in the motor! Can cause it to run slow!
It only requires 3 drops per bearing and 2 drops on the main shalf.

Al the best , Pete

Hi Pete,
I took the motor apart, cleaned and re lubricated it. It moved very easily and freely. The issue I believe are the caps that supply it. What I need to know are the values which appear to be 1.1mf though it's hard to read the writing given the condition of them.
I emailed some pics to Brad for uploading and hoping that when they do go up, that someone can identify the caps so I can replace them.
Cheers

Photos uploaded to Post 5.

I can't quite make out the labels on those caps, other than "11(?) MF +/-10%" so it seems the answer is there if you can read it clearly.

I just scrapped a tape recorder and it had a large 2μF cap next to the motor. The cap appears to be in fine condition.

So, 1.1μF might be approximately correct. In fact, I can see 1.1MF +- 10% in one of the photos.

I think you may be right about the 1.1 -- with the decimal point halfway up the 1.

Thx guys, as to the voltage of the caps, I'm guessing minimum 250vac
I'm guessing if I can get them out, I should be able to see how they are wired

I'd say 440 or 450 volts. You need to cater for peak voltage (plus some head room), not RMS voltage.