Beogram 1900 possible motor issue
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Hello, I’m new to this forum, but not to audio forums. Now that I have a couple of Beograms, I figured I should get on this forum and learn a few things, and hopefully be helpful at some point. I got into audio back in the 70’s as a teen. Mowed yards to earn money for my first system. Right after college, I bought a Beogram 1700/1800 (can’t remember which one) with a MMC2 cartridge. I was asking myself if I was nuts, when I heard that the cartridge would cost the same as the turntable. Today, I have a RX2 and a 4002 that needs service. But today, I am here to get help a local elderly gentleman who brought his 1900 to me. It wouldn’t power up. It has sentimental value to him, so I’d like to get this working for him.
What I can tell you about this 1900, is it’s clean. I was told this didn’t get a lot of use, and it looks like it. I used the MMC 6000 from my 4002. I don’t know if that “should” work, but I wanted something on there, and the MMC 6000 has the same mounting style. He can’t find his MMC 4000, so I’m going to get one from someone I know that rebuilds these. But for now, I’m hoping I can get moving on this to make sure the table will work before buying a cartridge.
The original problem is the platter won’t spin. The power cable is fine. I get current to the motor. In fact, when I push the copper colored washer (part 109 in the service manual), I can feel some vibration telling me current is getting to the motor. For this reason, I assume the motor needs to be cleaned and lubricated. But I have read some posts online about the motor in this not being so good. I’m hoping it is useable.
I have learned over the years that when I work on gear, there are always surprises. Since I’m trying to get this done in the next few weeks for this gentlemen, I figured why not ask first to see if anyone has any tips and tricks on things to focus on, try, and/or avoid. I have the service manual, but it is more useful as a parts diagram and schematic.
Here a pic with the platter on. There is a little crack on some rings, but seems to still be good. I’ll leave that alone. The tonearm and top plate are in good shape.
Can you rotate the motor by hand?
If not – take it apart, clean the spindle and replace the bearings.Martin
I would start with the power supply and check if you ar getting the full 12.5V when the motor is trying to run. I would also consider replacing C1, C3, C4, and C5.
I appreciate that Mark, thanks!
I’ll dig in tomorrow. If I don’t have the right values on hand, I’ll have to order, which means it could be a week to get those back, installed and tested. But I will update this thread with my status as it changes.
This is an odd duck. I was looking at the linkage, and the +/- Turn dial. Adjusted that and the motor slowly stars to spin. In slow motion, the tonearm swung into place. The speed of the motor slowly increased through the process, but still not fast. But it was spinning, so maybe I just need to service the motor for good measure.
Is there a “best” way to service the motor? As in, I can remove the bottom cover to access, but it is preferable to pull the entire assembly off?
Unless the spindle runs VERY freely by hand (read: run down 5-8 seconds or more), it will need service.
Yours will, by the sound of it.Martin
Bingo! It moves only when I move it. There is no play, or spinning on it’s own once I let off.
Thanks! I’ll get that serviced. I have a synthetic lube called Super Lube that I normally use. I assume this type of motor is ok with that?
Motor service
I have three pics here as reference. It may help someone else since I can’t find many pics of a 1900 motor.
There is a sintered bearing in the cover with a plastic plug on the outside. I am guessing there is no harm in pushing it out from the bearing side.
There is an oily substance covering the housing the motor shaft sits in. I am guessing that should not be, and that it simply migrated over the years from the only spots that should be lubricated, the bearings. Am I wrong?
Since the service manual doesn’t address removal, I am also guessing the motor spindle needs to be pulled out from the top, after removing the idler wheel, and it looks like removing one motor spring will be enough to clear the flywheel
Just adding oil in “free form”/ as drops, won’t provide a lasting solution.
It will be pressed away as the motor runs.
And only few synthetic oils have the right additives for running with the metal alloys used here anyways.The bearings are sintered. They will need oil infused into the pores in the
metal material from where it is pulled by capillary action when the spindle rotates.
Reoiling can be difficult seeing as the remains of the old oil needs
to come out first in order to infuse new oil.
Best and easiest is to replace the bearings altogether.New bearings here, correctly oiled.
Your bearings may – or may not – have an additional flange, which is of no practical importance here.
Martin
Good to get that confirmation, thanks! I’ll order those now and let you know when I’m ready to roll. Since it’s coming from EU, who knows how long it will take. What are those felt washers for? I don’t see any place for those.
Last year I was lucky to have access to a food bag pump setup to infuse bearings. No longer, so I agree with your comment. I can send the ones in here off to a buddy who can do, and keep for future use.
I just edited my above reply to be more specific.
The felt washers are oil reservoirs sitting around the bearings.
You will see when you take it apart. (Yours will have hardened or at least run dry).
It’s a special technical felt material meant specifically for this purpose.
The bearings pull oil from the reservoirs to replenish and compensate for what is being used.Martin
Thanks for that clarification.
One point on removal of the motor spindle. Am I correct in thinking that is better removed from the top side?
You need to take the motor out. Undo the three springs etc.
Then remove the idler wheel and pull off the pulley.Martin
Perfect, thanks!
Are you familiar with Super Lube multipurpose synthetic grease with Syncolon®??
Perhaps not that exact product, but I know a thing or two about sinter bronze bearings,
and I have had my hands on lots of things with names beginning with “super”.
I remember one product was advertized for use with space shuttles, for which I’m sure it will be fine.
But I threw most of it away. It didn’t do anything near what I wanted it to.
Now I think of it, perhaps it was because I didn’t have a space shuttle to use it with.Anyway, – if it has teflon or similar modern “floating”/”suspended” stuff, that gets pressed in to the pores in the
bearing material, cluttering them, it’s usually safe to deem it no good for sinter bearings.
And very difficult to remove from the bearings pores again as teflon and microplastics are not easily dissolved. At least not without leaving a mess behind.Martin
Based on your comment, this won’t be a good option.
Super Lube has PTFE https://www.super-lube.com/multi-purpose-synthetic-grease-with-syncolon-ptfe-21030
What would you suggest?
Grease won’t do.
It has to be an oil, and it has to be light, homogenic and “self-dissolving”, and of course have the right properties and additives.
A mix of primarily SAE30 was used originally.The bearings from Beoparts are pre-oiled, ready to fit. So are the felt washers.
Just clean the spindle using IPA and a clean lint-free cloth.
And then keep the spindle clean. Leave no fingerprints on it afterwards, – there is no room for any.With the motor reassembled, you may need to align the spindle and bearings axially, or one or both bearings may end up running on “edges” instead of parallel on their plain inner surfaces.
Originally there was a tool for this task (not a very good one, really) but moving the spindle
around, pushing it sideways a little and rotate it by hand, paying attention to
the run-off time, will give you an idea of the sweet spot.Martin
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