Beogram 5500 Carriage Stuck – Solved (I think)

 

My Beogram 5500 (new in 1988) recently seized up after playing a record. The pickup lifted off to start its return, but the mechanism jammed and the pickup carriage stuck in a position that blocked attempts to open up the unit to investigate.  I had to unhook the drive cord from the small pulley (part number 1640 in the service manual - see link below), which is not easy, although removing the black plastic rear trim piece (1038) helps. With the cord released I could slide the carriage to the centre and swing up the chassis as described in the service manual 

The mechanism is very ingenious and it’s not obvious at first what’s going on because there are cams and levers hidden beneath the cogwheels. Eventually I found I could exercise the mechanism with the case open, cartridge removed for safety, drive cord removed, only the skeleton turntable fitted and with a 200g weight on the central plunger to simulate a record. After pressing Play, a small leftward nudge on the pickup arm makes the large pulley wheel (1634) rotate, just as if it were moving the now disconnected carriage. After a jam, I could lift off the pulley and rotate the large cogwheel (1604) manually to reset everything for another run.

Eventually I found out how to stop the jam happening. The problem seems to be caused by parts of the mechanism (possibly items 1608 and/or 1609) beneath occasionally fouling the underside of the wheel and interfering with the free action of the white slider (1603) on its upper surface.

Wheel 1604 sits on a thin washer so I tried adding a second thin washer to raise it up slightly. (It has to be ‘slightly’ because otherwise it would foul the turntable). Anyway with the second washer in place it no longer jams. Without the washer it jammed about once in five runs, but since I added the washer it hasn’t jammed at all in about 40 runs.

All the parts seem to be in perfect condition with no signs of wear and tear, so there’s no obvious reason why the original clearances should have altered. However my ‘solution’ seems to work and I offer it as a starting point for anyone else with the same problem. 

A search on the forum showed other similar cases but with no solutions so hoping the above helps. Here are some that I found: ‘Beogram 5500 stopped mid-play, tonearm also stuck’, https://archivedforum2.beoworld.org/forums/p/3697/33211.aspx#33211; ‘Beogram 5005, pickup arm stuck halfway’, https://archivedforum2.beoworld.org/forums/p/16657/144662.aspx#144662; ‘Beogram 5500 does not spin, block or stuck’, https://archivedforum2.beoworld.org/forums/p/35523/263627.aspx#263627.

Any insights from experts in the group welcome .

 

 

DAT:

Wheel 1604 sits on a thin washer so I tried adding a second thin washer to raise it up slightly.

I've since discovered the interesting post by tstag “5005, 5500 series linear tracking tonearm locking mid-track” at https://archivedforum2.beoworld.org/forums/t/29552.aspx. My solution of using an extra washer to raise the pulley slightly fits in with his discovery that arm 1609 was fouling the underside of the pulley. (Part 1609 on my unit is also not flat and looks the same as in his photo).

My extra washer and the original were 0.5 mm thick but the extra one had the wrong inside diameter and after a while ended up astride the original instead of above it, after which the jam returned as the pulley went back to its original lower position. Not having any other suitable washers I followed tstag’s example and removed arm 1609 completely. As he found, this also appears to solve the problem and it now seems to play 33 rpm records perfectly well. Since I don’t want to play 45 rpm records anyway that’s a good solution for me.

However there’s still a mystery about the function of part 1609. Contrary to Tstag’s experience, my unit still seems to drop the pickup correctly for both 45 and 33 rpm records and the speed indicator correctly shows 45 or 33. (I simulate a 45 record by putting a 70 g weight on the plunger).

Solderon commented that “I understand that the lever is designed to limit the inward travel of the pickup arm, i.e., that it can't go beyond the record label." This sounds plausible, but I find that even with 1609 missing, the pickup lifts off well clear of the label on a 33 record. I don't know what happens with a 45 as I don't have one to test.

What a pity B&O didn't make the pulleys and cogwheels out of transparent plastic so we could see what was going on! 

 

Today I got hold of an old 45 rpm disc for testing and the Beogram plays it perfectly. 

Conclude:  My 32-year old Beogram now works perfectly again on both 33 and 45 rpm records despite having part 1609 removed. Obviously B&O didn't include it just for fun, but at present I've no idea of its function. Meanwhile I'm happy that I can play my old records again. 

 

 

This is a very interesting post! I am just completing a Beogram 5005 restoration. It has exactly the same issue, and I came to a similar conclusion, till Martin suggested this is a common problem, solved by filing down the pin under pully wheel 1604 which snags with 1609. I also cannot fathom out what 1609 actually does, and did wonder if removing it will cause a problem. 

At the moment it is causing me an issue in that I cannot slide the carriage sufficiently to the left to close the top, and I suspect it is 1609 again (everything else works!)

Thanks for posting your experience with your Beogram 5005. My 5500 is still working fine with part 1609 removed, so I would recommend doing the same with your deck. My 1609 had become noticeably non-flat over the 33 years since new. I tried flattening it by clamping it to a flat piece of metal and heating it in a bath of boiling water. That made it flatter but I haven't replaced it into the deck because I can't be sure it won't warp again in time. It would be interesting to know if flattening it would have solved the issue, but refitting it is not an easy procedure, so I decided 'to let sleeping dogs lie'. Good luck with yours!

 

It has been an interesting exercise so far.

In an email exchange with Dillen (Martin), he said 1609 very commonly bends with age. Straightening it under heat apparently works for a while, but they bend again. I tried filing down the lug under the pulley wheel which seemed to work, but I thought if it (1609) bends further it will just happen again.

I've tried to understand what 1609 does; clearly B&O won't have put it in without a reason, and as far as I can see all it does is limit the travel of the arm assembly so that the user cannot move the stylus beyond the tracks. If there is any other reason, I cannot find it. So like you, I've removed it and indeed as you said everything works, except that I can move the pickup arm over the centre label of the disk, but all the automated functions still work. So I'm leaving it off for now.

Hopefully this will helps someone in the future (and it would be interesting to see if anyone else has a comment on this).

Now I just need to decide if I prefer my radial armed 5000 (restored a few months ago) to the tangential 5005. Just playing my first record as I type this, and I can't really notice anything in it so far.

Thanks for posting this, I may be dealing with the same issue. Or my TT is out of adjustment....actually I just realized my arm is not lifting so it's not the adjustment