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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
The tonearm was not lowering due to sticky and gunky old joints in my old 4002. I removed the solenoid, damper, etc. Got it all cleaned and lubricated and put together and it was working perfectly.
On about my 3rd album, the tonearm popped up about halfway through and I smelled that dreaded electrical smell. Upon inspection, my solenoid was melting The yellow wrap had turned brown and it was very hot.
I disconnected the solenoid and checked the voltage in the "down" position and it was around 31V. DC. But then I noticed resistor 56 smoking. This is a model 5503 (AC motor).
What a mess. What went wrong?
Well, i think I know what went wrong... The "c-clip' that holds down the lever that attaches to the solenoid was not snug in the groove. As such, the lever worked its way up to the point of not activating the switch at the top of its travel.
If I understand things, this switch is supposed to reduce current to the solenoid in order to hold the tonearm in the "up" position.
So I managed to fry the solenoid... Crap.
After I disconnected it, just having the unit plugged in caused Resister 56 to start a smokin' Any pointers would be appreciated.
Hi Cray
You are right, the Switch puts the 4R1 into Line with the Coil 0RL1 and reduces the Current, when Switch is open. When Switch is closed the Emitter of 0TR4 is GND
Check out if 1TR16 and/or 0TR4 is short to 4R1 (8,2 OHM Ressitor). Seems that 1TR16 draws to much Current, that only can happen when 0TR4 is short between B and E
Try to measure the Coil 0RL1 how many Ohm´s do you get there?
Best Regards
Christian
Thanks Christian-
The resistance in the Coil 0RL1 was only 2 Ohms. No question, it was fried. I tried to disassemble it in hopes of rewinding the thing, but when I tried to bend the end of the rod straight to remove the plunger, it snapped right off. The plastic was melted and it was impossible to unwind. So it had been under high current for at least two or three records.
I looked the rest of the circuit over and it seemed to be okay. R56 (the one that comes off of the collector of TR16) did get so hot as to turn the yellow color band black... And it was out-of-spec so I replaced it with a 47 Ohm 1 watt resistor.
So I've got it all working again. Switch is engaged and coil stays cool. I've let it run a couple of hours just to make sure.
Now I need to figure out how to get a replacement solenoid for my second deck. I thought about 3D printing a new spool and winding a new one, but I managed to break the end off of the plunger.rod which sort of scuttled that idea.
I'm sort of surprised that nobody has found an "off-the-shelf" version that could be adapted for this. Most of the ones I can find have a resistance of 20 Ohm (not 10) . I would need to match the throw distance, and the required current for initializing and holding and figure out how to mount it in the bracket.
I managed to repair the solenoid in my 2nd Beogram 4002. My original coil was melted because the current limiting switch did not get engaged for some period of time. It measured about 2 Ohms of resistance and had melted the spool.
The first step was to duplicate the spool. I took measurements and duplicated spools with a 3D printer. Then I wound the solenoid with a drill using 28AWG enamelled wire.
The interior plunger of the solenoid was broken, so I had to construct a new one. For this, I used a computer motherboard stay that was 1.25” long and .25 inches in diameter. It was a very close match. Pairing this with a threaded rod let me recreate the bit that slides through the solenoid.
I wrapped the solenoid in electrical tape and took care to insulate the wire that runs out the hole in the spool and between the spool edge and the metal bracket. Then I pushed the old sleeve through the assembly and screwed the rod into the plunger.
Presto: a new solenoid. I measured 9.2 Ohms resistance which is close to the 10 Ohms of the original.
I Installed the solenoid and it works just as expected. If anyone wants to try this and wants the 3D printing file to make a replacement spool, let me know.
I have one nagging problem left, but I’ll post that in another thread.
Hello Cray,
I am brand new to this forum. I have just experienced the dreaded toasted solenoid you speak of here. Beogram 4002 (type 5503)
I have many questions regarding this repair. Too many to list here. I will tell you in advance that I am a novice in diagnosing this particular machine but am very mechanical and can solder.
I have removed the solenoid and taken apart the rod from the plunger piece ( it actually screws out by the way). My question for you is, how do you remove the copper sleeve (with spool attached) from the bracket? I don’t want to mangle it.
Also your post mentions your making a new Spool and re wiring it.I don’t know if I have the expertise to perform this task and will ask you if this is something that you might have time to do for others?
I have emailed you. Don’t know if you got it? I have other questions for you about this machine.
I will start a new post and ask more if I don’t hear back. I don’t know if this message goes out to all or just to this part of this thread. Please PM
me.
If anyone else can help, I would greatly appreciate it.
thanks,
Cliff
I am new to this website and this will be my first post.
I’m happy to find your post about this problem as I too have experienced the dreaded fried solenoid.My question for you is how do you remove the copper sleeve from the bracket?
I have already removed the rod and plunger ( the rod is threaded and unscrews from the plunger).I want to remove the bobbin for closer inspection to access a repair if possible.
I am not confident in my expertise in performing the rewind task, as there are too many variables beyondmy experience. Is this something you are willing to do for other people with this problem? Yours looks like it worked out fine.
Also I may need to replace R56 transistor as you have done. Is percentage tolerance important to this part?
let me know,thanks,
cliff
Hi Cliff-
It is hard for me to remember, but i think the copper sleeve can be pushed out in one direction. One side is flanged way more than the other so I would try to work it out the easier way.
If you want to try to replace the solenoid, my 3D design is on a website called "tinkercad.com". Search for "Beogram 4002 Solenoid" and you can find it and order one printed and sent to you.
Winding the solenoid is not difficult. You can see in my photos how I did it with a drill. Just wind enough wire on the spool to fill it up. It doesn't have to be perfect to work. The printed spool has a hole in it and a groove to accommodate the wire. It is important to get the right gauge. Measure the resistance of your spool after you get it wound.
Also, I would measure the resistance on your existing spool just to make sure it is fried.
Good luck!
Jeff
Thank you very much Jeff!
Measured my solenoid. 0.2. plastic spool has melted itself fast to the inner core.
my work is definitely cut out for me. (No pun intended)
thanks again!
Looking through my box-o-parts, I found my first attempt at winding this solenoid coil. It measures 7.5 Ohms and it may work fine. I think I re-wound a second one that got closer to 9 Ohms and that was the one I installed in my repaired project.
Yours for free if you want to give it a try. Just drop me a line as to where to send it.
Oh boy!
please PM me and I can give you my address!This would be perfect!
thank you very much!