Rock Ola 1475 - Tone arm landing Speed

[bonnie59]

Hi There Everyone,
I am new to the board as I have not long taken delivery of a beautifully restored Tempo 1 1475.
As an Engineer I already have a list of things that I want to refine a little to get it working spot on.
One thing that bothers me a little is the speed with which the Tonearm lands on the record. I am told a resistor inline with the pickup arm motor is the only way to reduce this. I was wondering of anyone has any experience of this issue and have sucessfully adjusted the landing speed?
Many Thanks Bonnie59

[Ron Rich]

Hi,
Have you checked the service manual--schematics-- I don't recall if that motor was slowed down on that model ? Ron Rich

[jukenorman]

No, no slowing resistor on a 1475. One thing to check - if the selenium rectifier has been replaced by a silicon bridge, then the DC voltage will likely be a bit higher than the nominal 28V, causing the gripper motor to run a bit faster.
Norman.

[bonnie59]

Thank you for the comments.
I have only managed to get hold of a reproduction instruction manual and parts list so far and am still hunting for a service manual.(Hunting for nice originals of both, but that might be a long wait!)
The schematic does not seem to show any resistor inline with the gripper motor, so agree with what you say about there not being a slowing resistor.
Where would i find the selenium rectifier to check if it has been swapped or not? Control Box Assembly?
Is fitting a resistor in line something that has been done by anyone? If so does another model employ one already that can give me an idea on size / power rating maybe?
Many Thanks
Bonnie59

[Ron Rich]

Hi Bonnie,
Did you check our FAQ's section for sellers of the manuals-- I don't think you'll be able to locate "originals"-- but the suppliers listed there do supply pretty good copies--be sure you ask for the "package"----Might post this in the "parts wanted section" -- and hope ??
Later models did employ a "slow down", "switched in", resistor-- I really don't think it's necessary on the older ones, due to motor differences ? You would need to install a resistor, and a "switch" of some kind, or you will be "waiting all day long", for the needle to land ! Yes-- Rectifier is located on-in the "Junction box". Ron Rich

[jukenorman]

Another thought - I see you are in the UK. You didn't say whether your 1475 is a US model or a German Nova one. If you want to compare, check the archive at jukebox-world.de. The Nova models were built as 220V AC supply. Maybe you need to check the 28V DC (under load), as a first step?
Norman.

[bonnie59]

Thanks for the thoughts. Switching in a resistor and the last second sounds sensible if thr resistance value really slows the motor down. I guess I had in mind a small fixed inline resistor to just drop the supply voltage a small amount and slow the whole grip cycle just a little. The speed isnt far off, just needs calming down a little I feel!
My 1475 is a US model. But as you say checking the voltage at the motor sounds like a good starting point. Just need to find some time inbetween working and being Dad to a 8 month old and 3 year old to do so.
Really appreciate your thoughts Gents. Will get back to you!

[Ron Rich]

Hi Bonnie,
Has the old rectifier been replaced by a bridge ?Like you note--check the voltage being supplied--Ron Rich

[bonnie59]

Hi,
Finally got around to looking into this issue and have found that the supply voltage to the gripper motor was only a little over the 28V.
Have rigged up some test wires and have experiemented with some 25W resistors and found that a 10Ohm slows it acceptably, however occasionally the lateral wobble on the tone arm can cause the record to reject straight away. Upon investigation the siding surfaces on the cam and flat metal spring that is designed to hold the tone arm against the cam are very dry, as is the whole gripper mech.
Going to flatten and maybe fit a new spring and lubricate all sliding surfaces to make for a smoother gripper and tone arm cycle before deciding on a resistor value. Question is what do you guys use for greasing / lubrication the tone arm cam / pin / spring surfaces and more generally the gripper mechanism? How frequently should it all be re-greased?
Many Thanks

[Ron Rich]

Hi Bonnie,
Read the "stickies" (red pined posts), both here in the RockOla section and in the FAQ's section ! Ron Rich