BeoGram

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Sat, 20 Nov 2010 08:00:09 GMT

You know the original piece should still be in there somewhere. Instruct your tech. friend to remove the switch panel and look between panel and logic board, and all around that area. Could have also slipped under the main PCB, arm assembly etc.. Also make sure you take a copy of the manual (preferably printed) with the record player!

Re: Beogram 4000: The lights are on but nobody is home

burantek — Fri, 19 Nov 2010 13:45:57 GMT

Olly,

Thank you very much.

1.) I packed this 4000 up and it is ready to go for the ~4 hour trip to see Benny -I just haven't made it over there yet! With the holidays coming, I may just do a big rounder and also visit my store of record, Atlanta.

2.) I actually have the original mirror as well as a spare that the previous owner had made. I have fiddled w/ the placement of both, but will let it be dealt with during the overhaul. As far as the window... I will try plexiglass or similar -the angle (slope) will be the killer!

I will keep you posted.

Regards,

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Fri, 19 Nov 2010 13:18:21 GMT

How are things doing Jaff? I hadn't forgotten about the little strobe window - I pulled the player apart last night and made some notes. You know, a couple things I didn't note down like the step dimensions but this is to accommodate the thickness of the metal so that can be measure by you.

Also I forgot to make a proper measurement as to how far the prism shifts the image. I placed a pencil about 30mm below the top, (rough guess) the pencil had shifted by it's own width. This is obviously the primary function here.

I am sure it would be possible to fabricate this with careful cutting of suitable plastic and a lot of polishing but it really would be hard work!

Not sure if anyone has any spare parts they could send your way!?

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Sun, 19 Sep 2010 11:16:43 GMT

Well if I were you I would try the transistors for what they cost and then consider the 4 hour drive but I can understand why you might be worried.

of course, if there is anything wrong further upstream then things start getting quite complicated, although a meter should surfice for quite a bit of ff work but more than likely beyond remote help.

About the motor stalling yes you would think the belt would slip and tbh I am not sure what the motor pulls under stall but the transistors I think are rated at 500mA - if the transistors are old and tired then they might give up far before this..

Keep us up to date however this pans out :)

Re: Beogram 4000: The lights are on but nobody is home

burantek — Sun, 19 Sep 2010 10:52:06 GMT

Thanks.

I had the same thought... with the transit locked up anything is possible, though one would think that the transit belt simply would have slipped under load.

I am at a crossroads with this. The big determiner is time. I have two options as I see it.

1.) Source the parts from Martin (or locally) and try to bring this back to life myself. My concern is that after replacing the rather trivial transistors... what else might arise? It would mean probably a ~1 month project, at least? Furthermore, beyond basic tools... I don't have a scope, etc... which would likely be needed as I progress.

2.) Likely the route I will take... I have talked to Benny Amina @ Modular Electronics in Atlanta about the BG. He does restoration work on the 4002/4 and is about ~4 hours from me. He is also the B&o authorized service rep for my region. He expressed an interest in looking at the BG. After the diagnostic work here, I am confident that this BG will live. I think I may just pack it up and drive it over to him for a full service (and maybe bring my BM6000 QUAD to really get him going!).

With that said, I learned a great deal from this, especially w/ regards to the assembly of these units. In fact, I took the opportunity to go through (3) other BG's at the same time. All (3) are 4004's and have been sitting in boxes. I now have (2) perfectly functioning units, and (1) parts unit thanks to this, so I am very happy.

Short of anyone adding to this thread, I will post back as this develops.

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Sat, 18 Sep 2010 17:36:35 GMT

Personally I would replace 28, 31, 29 and 30. tr30 definately goosed and the other readings aren't correct. Not sure what you mean by 'ce not OL'?

Of course you could buy x amount off Dillen or other source like ebay (maybe get a cap and belt kit too?) and replace all 8 as you normally buy these components in multiples of 5 ect.. That would rule out any 'faulty under load' transistors.

I wonder if the jam was responsible for the overload in the first place?

Good luck :)

Re: Beogram 4000: The lights are on but nobody is home

burantek — Sat, 18 Sep 2010 14:56:53 GMT

Thank you so much for your time! This is really fun!

mV Diode test from B leg (CE never tested to be OL -always returned mV values).

NPN

1.) 1TR27: (+ on B) BE = 687 / BC = 683 | (- on B) BE = OL / BC = OL | CE not OL

2.) 1TR28: (+ on B) BE = 837 / BC = 574 | (- on B) BE = 880 / BC = 671 | CE not OL

3.) 1TR31: (+ on B) BE = 627 / BC = 613 | (- on B) BE = 908 / BC = 903 | CE not OL

4.) 1TR33: (+ on B) BE = 692 / BC = 688 | (- on B) BE = OL / BC = OL | CE not OL

PNP

5.) 1TR26: (- on B) BE = 689 / BC = 682 | (+ on B) BE = OL / BC = OL | CE not OL

6.) 1TR29: (- on B) BE = 1020 / BC = 661 | (+ on B) BE = 1217 / BC = 953 | CE not OL

7.) 1TR30: (- on B) BE = 484 / BC = 001 | (+ on B) BE = 490 / BC = 001 | CE not OL

8.) 1TR32: (- on B) BE = 684 / BC = 682 | (+ on B) BE = OL / BC = OL | CE not OL

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Sat, 18 Sep 2010 13:35:52 GMT

There is clearly at least one transistor that has an internal short - either tr30 or 32 maybe both. When testing transistors I normally isolate the base or any two of the legs and perform b-e > b-c then e-c

So say on TR31 which is an NPN type you want to do the following..

positive lead goes on base, now between base & emitter =0.6v then base & collector the same. swap leads round (negative on base) and all readings should be OC. Then do c - e should also be oc out of circuit.

In circuit measurements can complicate things as your meter might be measuring other components too.

Now on TR30 it is a PNP so you should be getting a 0.6v reading with negative lead on the base and so on.

Go through each transistor like this and post the results here.

Re: Beogram 4000: The lights are on but nobody is home

burantek — Sat, 18 Sep 2010 12:05:13 GMT

OK...

I have continuity from 8009010 to 8009012 -No voltage there either.

Transistor tests I picked up from this thread.

kOhm test

1.) 1TR26: CB = OL / CE = OL

2.) 1TR27: CB = OL / CE = 1.005

3.) 1TR28: CB = 1.005 / CE = 0.439

4.) 1TR29: CB = OL / CE = 0.642

5.) 1TR30: CB = 0.002 / CE = 0.621

6.) 1TR31: CB = 2.243 / CE = 0.418

7.) 1TR32: CB = OL / CE = 0.002

8.) 1TR33: CB = OL / CE = 2.245

mV Diode test

1.) 1TR26: CB = OL / CE = 958

2.) 1TR27: CB = 686 / CE = 571

3.) 1TR28: CB = 576 / CE = 359

4.) 1TR29: CB = 960 / CE = 492

5.) 1TR30: CB = 001 / CE = 480

6.) 1TR31: CB = 616 / CE = 344

7.) 1TR32: CB = OL / CE = 001

8.) 1TR33: CB = 692 / CE = 616

Re: Beogram 4000: The lights are on but nobody is home

burantek — Sat, 18 Sep 2010 08:26:13 GMT

Thanks for posting back.

Disregard the errant screw comment -wrong BG (I have a 4004 apart right next to it for comparison). I also found a spring clearly from the factory wedged in near the PS on that one as well! Must have been assembled on a Monday morning! As far as the location of the "transport" screw... You can see the through hole (which does not exist on the later 4002/4) in your fifth pic. It is between the solenoid and the lower rail.

I had some time to play again. I do not have voltage on the motor, measured at the solder points on the board.

Yes, you are right about testing... but this is very close! The album, stylus, etc... were all just junk level testers.

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Sat, 18 Sep 2010 05:32:56 GMT

Can you not see where this screw might have originated from in my pictures? Have you zoomed in to maximum size?

Regards the servo motor I doubt this is faulty. Check the transistors that form the H bridge are ok. If they are then maybe you could check the motor by resistance check or putting the leads to a couple of good aa batteries (e.g. open a remote control and touch leads to batteries open end) or a bench supply. I would think 3V should be ample to test. Obviously diconnect the motor first!

Oh you should tell yourself off for testing a record at this time - I would suggest you hold back until you are happy that everything is working nicly and that includes lubrication. Not worth damaging a stylus or other parts!

Re: Beogram 4000: The lights are on but nobody is home

burantek — Fri, 17 Sep 2010 08:43:40 GMT

OK...

BIG update...

I think this may end up being a rather short-lived thread! I hope I didn't just jinx myself.

As the OP posted... The lights are on but nobody is home. His description pretty much summed the BG up upon its arrival to me. In dealing with John, it was my understanding that the unit would be a bit of a crapshoot and may just end up being a parts unit. As the TT arrived in partial state of assembly, I first put it all back together to gage it in its entirety. I then broke it back down for evaluation.

Cosmetically: I think that the unit is not too bad. A little "patina" adds to the history of some of these older pieces. I think that some folks can drive themselves crazy striving for that last little measure of making something look like it just came out of the factory. I will add some pics when I have a chance... but all-in-all... The trim looks good, the wood needs to be dealt with, and the dust cover is just beautiful. John must have spent hours polishing it up and it really looks fantastic!

A general clean up, some sorting through my parts bin and we should have a winner. One interesting point... when the beancounters got involved and the 4002/4 was born... they actually changed the dust cover strip from an aluminized tape to an actual strip of aluminum -seems odd! At any rate, the original tape strip is too far gone. John supplied a really nice looking strip of brushed stainless (not aluminum) that I will use.

Electronically: Hmmm... First thing I noticed is that the mains lead had been changed at some point with some ugly acorn style terminals -yuck. I will likely replace w/ an original soldered in properly. DIN plug is still there though (no typical USA RCA conversion)! There is some corrosion present in the socket -so I may go ahead and replace it at the same time as the mains lead.

Without anything in place, tapping the ON switch brings light to the control panel and arms. Switching between 33 and 45 lights the appropriate fine adjust screw. Depressing the traverse and U/D switches does nothing. Motor (OM2???) just sits there. Well, I should be able to move the transport back and forth by rotating the drive screw. I start spinning the pulley with my finger and off she goes! And stops! Spin it back -off she goes and stops! This is clearly some sort of physical stop -something lodged in the mechanism? Hmmm... I'll sleep on it.

Last night... Welcome to Mezzavino Engineering. That would be: Half a bottle of red and let's mess with the BG! OK... where were we? Oh yeah -transport won't budge. Wife isn't home, so I plop the stripped BG onto the stove top and slowly start the screw in/out process -repeating for about 5 minutes, when... what is that?!?! Hmmm... a small cad-plated looking screw with a flat washer wobbling back and forth in its socket every time the transport moves. It is located just south of the solenoid and just doesn't look right. It looks like it is acting as a transport screw!!! The 4002/4 doesn't have one... the 4000 owner's and service manuals don't show it, and of course, the setup manual -which I don't have ...might! (anyone?)

OK... gulp of vino... that screw is coming out! Back to spinning the drive screw in... THAT WAS IT! The transport went right on her merry way. Back and forth a few times... we are good to try a record.

Place the platter, belt, cartridge, etc... Now remember, the transport motor is out -so I had to manually drive the transport. I depress the ON switch, everything lights up. I spin the drive screw again... Needle gets to the edge of the record -and drops! I lower my ear to the cartridge and I can hear the music. I try U/D switches -beautiful! I tap the OFF switch and reverse the spin of the screw and drive the transport back home. As it depresses the limit switch -presto, off it goes!

So, where am I? I have what seems to be a functioning TT w/ the transport motor in question for now. From the flow chart (cursory look) what voltage should I see there? If it is the motor, will a 4002/4 motor work? Also, this still needs a thorough cleaning and lube still as well as maybe reheating solders, and I haven't even amped it yet to see what I am getting out of it... more to come!

Re: Beogram 4000: The lights are on but nobody is home

burantek — Fri, 17 Sep 2010 07:57:22 GMT

From your earlier post...

Step1:
It is a single piece of plastic, flush on top but is actually angled maybe 15 degrees or more on the oposite side

Well, of course it had to have a ~15D angle on the bottom! Nothing simple with this thing... but that is its charm.

From your latest post...

Step1:
I think some of the pics explain what I found

Thanks a million, these pics will get me started! Please don't go out of your way to take any more. Let's see how this progresses -as I have a rather big update to add. Thank you also for the wonderful write up with tips -I will print this and keep it by my side as I dive further into this. Your time is certainly appreciated!

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Thu, 16 Sep 2010 18:07:23 GMT

Hi I quickly uploaded some pics that I took - I took many more but unfortunately these are all I could recover from my cameras memory card after my hd suddenly failed! Hopefully they will be fairly usefull!

I will take some pics of the underside of the window but as I will have to partially dismantal the player it will be next week now.

The pics I show here cover some of the problems I had but also will give you a rough idea of what to expect in the way of bits 'n' bobs.

My beogram was a mess so I totally stripped it before power on including pulling the arm assembly off it's rails and removing both sensor and pickup arms. Also referbed the keys as they were loose - moving these on and off can be accomplished easily without forably bending the spring tabs as some people seem to think is nesecary - they simply slide on laterally after clipping the bronze(?) springs in place...

I think some of the pics explain what I found and I may write my experience up some time - not my strongest of skills though!

Here are the pics - http://s170.photobucket.com/albums/u270/olly-k/

Any questions or further requests please ask but bear in mind there are far more experienced people on this and other decks on this forum so you might want to get their attention!

BTW my deck is running quite nicely now i was very lucky in that little was wrong electronically - missing resistor (it had blown in a spectacular manner!) and about 4 blown transistors which drive the servo (I suggest you check these - metal canned BC140 / 142 inc. smaller drivers all together on main board) and a couple of electrolytics.

Oh check that the solonoid activates the little switch to limit current (accompanying dropping resistor is on the switch board, associate solonoid drive tranny is next to this bolted to the chassis) - anyway this switch is important or solonoid could melt, at the very least it will cause problems - the switch board may have left it's soldered mountings, it will appear to bend back away from solonoid if this is the case..

What else, hmm belts are an obvious one. My player had the original round servo belt inside but V notched pulleys which I didn't expect. Also it is worth checking the switches on the positional board as these may be bending with age - they are only copper strips under the board and they could be tarnished too. Don't forget the sprung metal associated with these best to bend for optimal play before testing so switches are operated and no snagging occurs. Positional adjustment can be carried out afterward.

Lubrication is the big thing on these and I have experimented with a couple of different types - sewing machine oil only for bearings (watch that the cartridge cantelever does absolutely not move when finally testing - If it does your arm is not free enough! it helps to remove sensor and playing arms to free up any stiff bearings as it allows for greater movement to work oil into bearings) and main motor.

I tried teflon based oil for the metal runners. I have used a fine grease for the worm drive. Of course the damper will need to be cleaned and new lubricant applied. Again I used teflon as I figured as I am keeping the deck in family I can always undo what I have done. Sewing oil is as good I woudl think but I have to be different! Original stuff recommended in the manual is not oil at all as far as I can make out maybe somone else can elaborate?

This is quite a big job and not for the impatient or inexperienced. Also, after getting everything working the proper setup proceedures should be followed with absolute precision and repeated as nescesary. I also found the tracking force was no longer accurate so can not rely on zero gram adjustment. This may vary from deck to deck but worth checking with some scales.

Very satisfying when the player works though. Wow I just seen what I wrote Hope it makes sense!

Re: Beogram 4000: The lights are on but nobody is home

Step1 — Thu, 16 Sep 2010 16:28:40 GMT

It is a single piece of plastic, flush on top but is actually angled maybe 15 degrees or more on the oposite side, I suspect designed to bend the image to a more favorable angle - mine also offers a slightly distored and less than perfect image so not sure if this is normal or not. I remember it being slightly clearer as a child but that was 30 years ago!

I will try to get a piccy but tomorrow I am quite busy.