BeoGram

Re: Beogram 4004 - Arm fails to lower!!!!!

Ben — Tue, 17 Jun 2008 02:05:37 GMT

Ok, So i've made a bit of progress... not meaning to though.

I took the main PCB out, to check for burned components, put it back in, and the arm will now will drop at the 12" LP position.

Moving the tonearm to the left though, the carriage will not follow, so there are still some glitches. If I put on a single, the arm still decides to drop at the LP position.

I'm thinking along the lines of recapping and seeing what happens after that.

Does anybody have a clearer version of the service manual? I can't read the schematics on the one on here.

Thanks,

Ben

Re: Beogram 4004 - Arm fails to lower!!!!!

tournedos — Mon, 16 Jun 2008 13:24:24 GMT

It's actually the rotating stripes the sensor arm is trying to see, not the record. If the lamp/sensor system wasn't working, the arm would lower on the platter! Therefore, I think your problem is in the logic following the sensor, not in the sensor arm. Something in the sensor signal filter / amplifier, or after its output, is "stuck" in the position where the rest of the logic thinks the platter signal is seen by the sensor. A failed diode, or something?

Re: Beogram 4004 - Arm fails to lower!!!!!

Ben — Mon, 16 Jun 2008 12:28:19 GMT

Ok, so this is now my Beogram!

I cleaned the light lense as it was all murky, and have tried various positions for the lamp inside the arm, but it still fails to 'see' the record. The arm goes across the LP, the speed changes to 45, hits the end, then returns.

I read that a marginal lamp can cause problems, this one still looks ok though.

Any thoughts?

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Sat, 05 Apr 2008 11:04:46 GMT

Still not got round to sorting it out yet Kevin, but thanks for the update.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

kevinoils — Sat, 05 Apr 2008 06:35:15 GMT

Hi Craig

I realised I said adjustment of solenoid, when I meant moving the diaphragm by lossening screw at base and moving this left and right slightly, its in the Beogram 4002-4004 manual sect 3-5

Hope you got this sorted!

Cheers

Kevin

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Thu, 13 Mar 2008 16:06:17 GMT

Thanks again Kevin, I have not had a chance to look at it since you last post. When I do I will try both, although I am sure it is the lamp that is the problem as the solenoid does not even try to move now.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

kevinoils — Thu, 13 Mar 2008 10:29:36 GMT

Oh Craig

I forgot to mention the solenoid adjustment at the base of the tone arm can be very tricky to adjust but there are loads of threads on Beoworld describing this, the slightest movement left or right can make the arm track backwards it seems or scanning towards the centre. It may be that you can do tiny adjustments to this until it tracks better and then tighten up again.

I have to stress though this is a patience job, and it can take a while to get right.

Cheers

Kevin

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Thu, 06 Mar 2008 13:52:19 GMT

Thanks Kevin, I will give it a go and see what happens.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

kevinoils — Thu, 06 Mar 2008 09:19:55 GMT

Hi Craig

I have had similiar problems with the sensor adjustment, but inside the sensor arm i have repositioned the bulb closer to the lense. It seems that the end of the arm the small plastic part with the legend on opens easily and can be slid out far enough to carefully reposition it.

The tone arms tracking to the centre I have experienced problems with this but adjusted the sensor and it has stabalised the motor and the arms tracking movement.

I hope this makes sense.

Cheers

Kevin

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Mon, 03 Mar 2008 14:36:31 GMT

NOOOOOOO. Things seem to be going from bad to worse with this one. Just thought I would have a listen to a record on it. So I connected it to my Beomaster 900. Pressed start now the arm goes all the way along to the end and returns. It won't even work with the up and down buttons. It is as if it cannot see the record. Could this be a problem with the lamp?

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Sun, 02 Mar 2008 11:05:13 GMT

Well I may have celebrated a bit too early. Now the arm loweres most of the time, seems to be getting better with more use. So I will see how that goes for now. My next problem is that when the arm gets to the ned of the record is does not return or lift. If I use the < button it goes to the end of it's travel and returns perefectly. tried cleaning the sensor lamp to see if that made any difference, but it did not.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Sun, 02 Mar 2008 10:26:21 GMT

Medogsfat:

You'll be fine mate. It's pretty straightforward once you make a start.

Chris.

It was very straight forward, once I got inside it. Cleaned all the old ~~glue~~ grease off. Even managed to get some silicon grease from my Dad last night (Seems that it also used on some models of cars for the ignition leads). Also greased the brass worm drive thing that moves the arm. It will need a set of new belt as the small one that drives the arm has stretched quite a bit. My plan was to replace these anyway, so I will see if Martin has some in stock. Just need to hook it up to my BS3000 to try it out the stylus I fitted as I am not sure of it's condition. May even treat it to a nice new SMMC20EN.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

Medogsfat — Sat, 01 Mar 2008 14:41:03 GMT

You'll be fine mate. It's pretty straightforward once you make a start.

Chris.

Re: Beogram 4004 - Arm fails to lower!!!!!

Craig — Sat, 01 Mar 2008 14:39:10 GMT

Cheers Chris, I will take a look later tonight, just got to pop out for an hour so. You might be getting a phone call if I get stuck.

Craig

Re: Beogram 4004 - Arm fails to lower!!!!!

Medogsfat — Sat, 01 Mar 2008 14:35:47 GMT

Craig, if you view page 3-2 "adjustment of magnet coil" diagram in the service manual you can see the see saw (possibly pantograph??) arrangement of this assembly. It is the pivot points which can become stiff. It's a while since I did this on a BG4000 (same system) and I think I had to disconnect the solenoid first - not sure though. Martin will probably know.

You shouldn't need to remove the cover to do this.

Chris.

EDIT:- try not to lose the screws eh?