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Tonearm or Reproducer Slowing Record

Posted: Tue Oct 02, 2018 11:56 pm
by adaytoolong
Hello Everyone:

My dad recently found my grandmother's old Birch 41A portable suitcase turntable in his basement and gave it to me, knowing I've got several old phonographs.

I have been slowly bringing it back to life. I disassembled and cleaned the motor (Thorens 531) and prettied up the case as best I could. Tonight I got everything put back together and tried to play a record. The metal reproducer is very heavy and weighs down the record, causing it to slow then stop. If I lift the reproducer ever so slightly while the record is playing for the first 30 seconds or so before letting it go, however, the record plays just fine to the end.

I'm not sure how to fix this problem. The base of the tonearm is a bit wobbly and I found what appears to be a ball bearing in bottom of the suitcase, but there doesn't appear to be a way to "open" the tonearm to look inside where the bearings should be. (It's also possible the bearing isn't even for the machine, since I also found a random straight pin inside the case.) Even if it was somehow missing a bearing, I'm not even sure if that's what's causing the problem.

Any ideas? I'd be happy to post pictures if that would help. I'd like to get this up and running again for sentimental reasons. Thanks.

Ken

Re: Tonearm or Reproducer Slowing Record

Posted: Wed Oct 03, 2018 8:44 pm
by pellicano1
adaytoolong wrote:Hello Everyone:

My dad recently found my grandmother's old Birch 41A portable suitcase turntable in his basement and gave it to me, knowing I've got several old phonographs.

I have been slowly bringing it back to life. I disassembled and cleaned the motor (Thorens 531) and prettied up the case as best I could. Tonight I got everything put back together and tried to play a record. The metal reproducer is very heavy and weighs down the record, causing it to slow then stop. If I lift the reproducer ever so slightly while the record is playing for the first 30 seconds or so before letting it go, however, the record plays just fine to the end.

I'm not sure how to fix this problem. The base of the tonearm is a bit wobbly and I found what appears to be a ball bearing in bottom of the suitcase, but there doesn't appear to be a way to "open" the tonearm to look inside where the bearings should be. (It's also possible the bearing isn't even for the machine, since I also found a random straight pin inside the case.) Even if it was somehow missing a bearing, I'm not even sure if that's what's causing the problem.

Any ideas? I'd be happy to post pictures if that would help. I'd like to get this up and running again for sentimental reasons. Thanks.

Ken
Ken, It can be one of several issues. The tonearm does sound like it needs to be greased. Ball bearings were used in the base. In order to do this, you will have to drill the rivets out to remove the base. When you replace it use a slotted machine screw or wood screw (whichever is appropriate) to re-fasten it. A screw shouldn't be a problem since the hole is countersunk and it will make it easier to service in the future.

Another thing can be the spring or springs. If you have a weak mainspring this issue will occur.

Check the governor to make sure it is adjusted properly.

And finally, if the bearing ball is missing from underneath the spindle you will have issues.

Hope this helps!
Steve

Re: Tonearm or Reproducer Slowing Record

Posted: Wed Oct 03, 2018 10:51 pm
by audiophile102
I had a similar problem with my Sonora until I discovered that inserting the needle all the way into the reproducer was a problem. Now I insert just 1/16th inch of the needle so that the needle contact point with the record is at a more pronounced angle. I no longer suffer from slowing of the record unless it requires more turns of the crank. :lol: I don't have a big heavy reproducer so I don't know how relevant my solution is to your problem, but you might want to give it a try and make sure that the spring is sufficiently wound up to play the entire record.

Re: Tonearm or Reproducer Slowing Record

Posted: Thu Oct 04, 2018 9:20 pm
by adaytoolong
pellicano1 wrote:
Ken, It can be one of several issues. The tonearm does sound like it needs to be greased. Ball bearings were used in the base. In order to do this, you will have to drill the rivets out to remove the base. When you replace it use a slotted machine screw or wood screw (whichever is appropriate) to re-fasten it. A screw shouldn't be a problem since the hole is countersunk and it will make it easier to service in the future.

Another thing can be the spring or springs. If you have a weak mainspring this issue will occur.

Check the governor to make sure it is adjusted properly.

And finally, if the bearing ball is missing from underneath the spindle you will have issues.

Hope this helps!
Steve
Thanks, Steve. This tonearm actually already has screws unlike many that are riveted down. Once I remove the tonearm, are you aware of a way to get to the bearings? It doesn’t seem to come apart.

I am unable to check the spring since it doesn’t seem to come out of the barrel. Any ideas there?

I will look at the governor again but I think it’s okay. Not sure about the spindle so I’ll look at that too.

I will also try the needle trick suggested by audiophile102. Thank you both for your ideas.

Re: Tonearm or Reproducer Slowing Record

Posted: Thu Oct 04, 2018 9:54 pm
by 52089
I might also add that worn needles and worn records can also cause serious drag. Steel needles should only be used once and then discarded.

Re: Tonearm or Reproducer Slowing Record

Posted: Thu Oct 11, 2018 11:40 pm
by adaytoolong
I've been messing around with this thing quite a bit based on some of the suggestions here. I can't see where there's supposed to be a bearing under the spindle. There's a small screw off metal "lid" that exposes the bottom of the spindle. There's no bearing under there, though. Is it missing? If so, any idea what size is needed? I can post pictures if anyone thinks they might be able to help.

The governor looks fine.

Does anyone know how to get to the bearings in the tonearm once I've unscrewed it so I can check those?

The more I look at this, the more it seems like the tonearm has too much "play" and it weighing things down. Any other ideas to try? If not, does anyone know where I might find a replacement tonearm?

(Sorry for all the questions, but this one is frustrating me!)

Thanks!

Ken