Tone Arm Weight

Replaced cartridge on Rockola 1454 and manual of course gives no guidance on proper tone arm weight. How should I determine the correct gram weight for the tone arm?

Best
Darrell

Well, what are you using as a replacement?

Those old R-O arms are pretty crude and unbalanced. With the existing setup you'll be lucky to get it to track well at 5 grams. You will need to set the trip contacts as close as possible to avoid having them loading the playing grooves.

I've always added a counterweight to all the 50's60's R-Os and eliminated that crude spring.

Rob

Rob

I used a P132-D cartridge.

I have the crude spring fully engaged with the tone arm and the gram gauge still will not measure the weight!

Any pictures of how you added a counter weight and how much weight did you use?

Best
Darrell

Darrell,
Check me as I MAY well be wrong here--My memory tells me that the LESS that spring is extended, the more weight is applied to the needle ? (4/5 grams is the correct weight) Let me know--
Ron Rich

ds100h wrote:Rob
I used a P132-D cartridge.
I have the crude spring fully engaged with the tone arm and the gram gauge still will not measure the weight! Any pictures of how you added a counter weight and how much weight did you use?
Best
Darrell

Darrel, I don't have any pic's of a R-O, but do have soem of the AMI I-200:
http://s1192.photobucket.com/user/Rob-N ... ort=2&o=11
http://s1192.photobucket.com/user/Rob-N ... ort=2&o=12

Ron is correct (big news, right?) extending the spring lightens the weight.

The real problem with all those old arms is that they are inherently unbalanced and throw all the weight forward. The arm literally wants to fall toward the stylus. this creates friction on the simple bearing and causes stylus hopping and wobble.

Rob

Update: Here is a pic of a 1465 that I sold to a record producer in 1998:

http://s1192.photobucket.com/user/Rob-N ... sort=3&o=0

I looked up his name, and was surprised to see a pic of the machine. You can just barely see the counterweight sticking up behind the arm. This one was modded with Pickering DAT-2 tracking at 2½ gm with home made pre and horn tweeter. Worked well, sounded very good and didn't ruin records.

Rob/Ron

Computer is down, will post picture when I can. There is an acorn like nut that has an Allen head screw in it. The more you tighten the allen head screw the more the flat metal spring moves away from the tone arm creating more pressure on the record. I have the allen head screw unscrewed as far as I can get which pushes the flat metal spring harder against the tone arm creating lighter pressure. I think Rob's idea about a counter weight is a good idea and I hope to implement that idea.

In replacing the cartridge, the two plus posts on the cartridge were jumpered and attached to the red tone arm wire. Likewise, the two negative posts were jumpered and hooked up to the black wire. This should have hooked the cartridge up in parallel. Result no sound? Where did I go wrong and how do I correct this?

Best
Darrell

Darrell, check your connections against this diagram (scroll down):

http://www.jukebox-world.de/Forum/Archi ... Tempo2.htm

Beyond that there is the possibility that a wire broke in handling -it happens...frequently. Simple continuity test from RCA plug to cart will tell.

Rob

--What I had meant to show was the positions of the pins on that cart NOT to connect it the way depicted. Connecting as shown would result in an out-of-phase connection that will cancel most sound.

Rob

Thank you for jogging this old man's memory. I had also been doing some work on the amp that I had forgotten about. In the process I had failed to plug the tone arm input plug back in

Sorry to trouble you. Sounds much better than the cartridge that was in the unit.

Best
Darrell

Darrell,
Just to help you remember--"plugging in ist goot" ! Ja !!!
Ron Rich

Ron Rich wrote:Darrell,
Just to help you remember--"plugging in ist goot" ! Ja !!!
Ron Rich

Once I was re-assembling a large flat-screen tv, and got distracted by a customer walking into the shop.
Later, after I replaced the back panel, (which was like 40+ screws) I realized the set had no sound.
goll-dern speaker plug was not connected!
Imagine the foul language eminating from my lovely mouth when I had to remove all those screws - again!

No wonder the paint is peeling off the shop's walls here!

Matt,
Don't feel too bad--I won't admit the number of times, when I have been building a new, Gen 2 SMC, MCU, that I have installed the display, or operational switches, on the wrong side of the board. ( If "Mr. Grumpy" sees this, I'll never hear the end of it ! ) That's to be filedunder "stuff happens" ! Ron Rich

Ron/Matt

It is nice to be able to laugh at our mistakes, guess it just proves we are normal and certainly serves to keep us humble!

Here is another one to make you laugh after buying a new horn speaker and capacitor I find that what was really wrong was a 7 OHM resistor that was open. Resistor has been replaced and old Jensen horn tweeter works great with old capacitor. Guess what is on the storage shelf for when they may be needed

Best
Darrell

ds100h wrote:Ron/Matt

It is nice to be able to laugh at our mistakes, guess it just proves we are normal and certainly serves to keep us humble!

Here is another one to make you laugh after buying a new horn speaker and capacitor I find that what was really wrong was a 7 OHM resistor that was open. Resistor has been replaced and old Jensen horn tweeter works great with old capacitor. Guess what is on the storage shelf for when they may be needed

Best
Darrell

Which just goes to prove that.. it's NOT always just a "capacitor".
So those internet freaks and their "recapping hysteria" - yeah, play mister wizard, go on.
When the problems still continue, let a "real" tech service it.
LOL!

Which just goes to prove that.. it's NOT always just a "capacitor".
So those internet freaks and their "recapping hysteria" - yeah, play mister wizard, go on.
When the problems still continue, let a "real" tech service it.

Matt, you are off base here. Commercial equipment such as a jukebox sees radically more service than home appliances. Added to that are years of neglect following their retirement from service and rebuilding is mandatory. From an electronic standpoint, capacitors are the single biggest impediment to good performance and safe operation.

Jukebox collection is frankly, a declining hobby and the people with first-hand knowledge of the old machines grows fewer by the year. Looking at the situation realistically, if the hobby is to have any future those of us with real information and experience must step-up to assist newcomers in getting these old relics working. Otherwise, a 400lb doorstop will not last long in a someone's home.

Calling earnest people "freaks" and "Mr Wizard" is NOT helpful. This forum is not about building up one's ego. It is about helping others with similar interests.

Rob/NYC

Guys,
I see "both sides" of this situation--I get components sent in to me for "rebuilding", that have been "Geppeto repaired", including, the one here now, that suffers from the use of acid core solder, on the PC boards! Therefore, I think one should self-assess the skills they possess prior to an attempt to DYI. "Cap kits" are OK--and true, that's USUALLY "the problem", but that's not true 100% of the time, as other parts do fail--- Which, I dono how to put this?? Leads to more problems--such as transformer failures, and sometimes, a fire---??
Ron Rich