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ARCHIVED FORUM -- March 2012 to February 2022
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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022

 

missing BG4000

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Craig
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Craig Posted: Tue, Oct 19 2021 11:56 AM

Following a protracted delivery process Justin was finally able to get this to me, seems it had fallen off DHL's radar a week or so ago and we feared the worst........

Craig
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This is the way to ship a Beogram around the country........

Craig
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Despite going walkabout the packaging appears non the worse for the ordeal.....

Craig
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Doesn't look like anything has moved around in the box... 

Craig
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All still very secure.............

Craig
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A very clean looking unit....comes with a set of capacitors and laser printed mounting brackets from Rudi, along with some LED's for the control panel.

Craig
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Craig replied on Tue, Oct 19 2021 2:12 PM

The unit is described as working with the following issues:

Neon lamp for speed indication not working

Tone arm refuses to move up or down

Some time on the work bench will confirm that no other problems exist.

Craig
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Took a peep inside.....reasonably clean with no obvious footprints indicating previous activity.....

Craig
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However the carriage drive belt looks very "baggy" and most likely loose.....

Craig
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The solenoid and assembly look gummed up, they don't move freely which will be contributing, if not the cause, to the tone arm woes.....I've also noted that the bottom leaf spring on the middle switch is not straight, I suspect its not breaking when the solenoid operates....

Craig
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Teased out the linkages and springs for a good clean and lubrication......

sonavor
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sonavor replied on Wed, Oct 20 2021 3:59 PM

Craig:

All still very secure.............

Now that is a properly packed Beogram 4000.

-sonavor

Craig
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Indeed Sonavor......almost bullet proof!

The lift arm was very very difficult to move back and forth....almost immovable with  my finger.

Craig
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Bit of persuasion and some light oil helped to free the assembly up..... 

Craig
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I noticed at this point that the nylon roller which supports the carriage on the steel rail upon which it runs was skewed off to one side, on investigation i found the screw was tightly screwed in but looked cross threaded......  

Craig
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Took it out and after a bit of a clean put it back properly....

Craig
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Re assembly started I thought this was a good time to straighten the audio muting switch that I suspect wasn't opening when the solenoid pulled in....this would result in the absence of one of the channels if it was to remain closed.... 

Craig
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Finished up mechanically......the whole assembly is now free moving and smooth.

Craig
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Turned to the neon lamp next and decided to just replace the existing lamp with a new one supplied by Justin, thought I may get lucky!

Craig
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Craig replied on Sat, Oct 23 2021 11:09 AM

And as those two items comprised the total of the ifentified issues I gingerly powered her up via the variac...no sudden bangs of flashes, smokey smells or anything else untoward.

With the platter in place i hit ON, platter spun, carriage moved inwards past the drop points and back again juas as it should, popped a disc on the platter and hit ON again, carriage moved to the 33 RPM drop point and stopped as it should......however the solenoid remained at rest, and I could dee no light from the neon lamp!....so on to the circuit diagram for some inspiration ;¬)

Craig
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Craig replied on Sat, Oct 23 2021 4:39 PM

Just as a test I have installed a neon lamp from one of my working beograms......now when I press ON the neon lamp flashes briefly and goes out, it displays this behaviour when I press the 33RPM switch also.....brief on and off. I will try the spare neon lamp provided on my working unit and see what happens. However this still doesnt help with the solenoid issue....I'm suspecting reed relay contacts.

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chartz replied on Sat, Oct 23 2021 7:33 PM

Hi Craig,

Yes, I had to replace them too. An easy task!

 

Jacques

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sonavor replied on Sat, Oct 23 2021 7:34 PM

Hi Craig,

Verify the AC voltage from the transformer secondary that powers that neon strobe lamp.  I believe those neon lamps have to have around 220 VAC in order to work.  I don't know what their operating voltage range is but I learned that they won't come on at 125 VAC :-)....which is what I was trying to use at the time. 


John

Craig
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Craig replied on Sat, Oct 23 2021 8:07 PM

Thanks for that John.....I was measuring 160vac at the terminals when the lamp was removed, there is a 27k resistor in series that will need to be removed and measured, god forbid its a transformer issue Erm..

Craig
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Well.....following on I have measured the voltage at the terminals of the neon lamp in a working beogram and get a steady 230vac....as expected. Back at the workbench I've disconnected the secondary windings which provide the power to the neon lamp, effectively bypassing both the series resistor and the reed relay switch.....and only measure 165vac...bit of a worry....

Craig
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While I was on  a roll I installed the spare neon lamp Justin sent into my working beogram only to confirm that its kaput!....I did notice this marked on the rear of the plastic bag which contained said lamp "used".....perhaps it should have said "goosed" (sorry Justin) Surprise

Craig
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While this sinks in I have continued to follow up on the failing solenoid action.....the switch from Hi to Lo at the base of TR10 is present and correct when the carriage reaches the drop point for the tone arm which is encouraging, the solenoid resistance is floating around 7.5 ohms which is also good.....ID3,TR10 and TR11 all measure up good....however OTR4 has failed. 

Craig
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So....I'm looking for a TIP41A to replace this little fellow......

Craig
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TIP41A on order....will await delivery, meanwhile I decided to take a look at 6D1 and 7R1 (connected to the emitter and collector of rogue TIP41A just to ensure any failures in those components contributed to the demise of of said transistor.....the Diode checked out fine, when I came to the resistor I had to remove the carriage slider switch activator and travel indicator....this is what I found, a deep scar melted into the transparent plastic arm......

Craig
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I have seen this before I'm thinking to myself.....and indeed I have, on the arm of one of my own beograms, in almost exactly the same place.

Craig
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Replacing the arm back onto the carriage I manually wound it in until I could see where the scar contacted with something that could have got so hot as to melt the indicator arm and discovered it lined up very nicely with the small black negative wire sitting a little proud of the other negatives......

Craig
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These wires connect the 8.2ohm 1W resistor 7R1 to neutral, I have replaced one of these in the past which was quite badly scorched....something to watch out for in the future....I know the plastic arms are hard to come by.

 

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sonavor replied on Mon, Oct 25 2021 1:02 AM

Craig:

Thanks for that John.....I was measuring 160vac at the terminals when the lamp was removed, there is a 27k resistor in series that will need to be removed and measured, god forbid its a transformer issue Erm..

In my Beoworld post from 2015 I tested the neon bulbs with a 27k ohm resistor, a step-up transformer and a variac to find where the neon lamp would start flashing.  For me the voltage had to get up to 179 VAC before the lamp starts to work.

John

Craig
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john

Sadly I'm only measuring 165vac at the secondary windings of the transformer, I have confirmed 240vac at the voltage selector switch and also at the input fuses...so the transformer is definitely suspect...any suggestions would be welcome at this point Erm.. 

However onwards and upwards.....whilst awaiting delivery of the rogue transistor I have hauled out the old capacitors.....

Craig
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And a proper bunch of raggy old scoundrels they look too, one had clearly thrown in the towel.....

Craig
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This arrangement looks a lot more comfortable complete with the laser printed bracket............

Craig
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And in the meanwhile this little fellow has been delivered.....

sonavor
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sonavor replied on Thu, Oct 28 2021 11:43 PM

Craig:

john

Sadly I'm only measuring 165vac at the secondary windings of the transformer, I have confirmed 240vac at the voltage selector switch and also at the input fuses...so the transformer is definitely suspect...any suggestions would be welcome at this point Erm.. 

However onwards and upwards.....whilst awaiting delivery of the rogue transistor I have hauled out the old capacitors.....

Hi Craig,

You could do what I did on my Beogram 4000 where I did not have the available 200+ secondary to run the original neon lamp.
In my case I decided to tap off the 10 VAC secondary and turned it into a driver for an LED.  That work is also on that 2015 Beoworld post (towards the bottom of the page).  I described how I connected things and included a diagram.  I used a two color LED like Rudy does so I could mix the colors to reproduce the glow of the original neon lamp.  The solution works well and that Beogram 4000 is still operating great here at my house.

John

Craig
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Craig replied on Fri, Oct 29 2021 8:10 AM

John

Thats really interesting....do you know if Rudi has a kit for this mod? unlikely I know, could you let me have a bit more detail around the manufacturer and model of the LED's you used.....i take it the full wave rectifier is a standard component along with the trimmers....this may turn out to be my only recourse ;¬)

Craig

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Craig replied on Fri, Oct 29 2021 8:12 AM

Oh and one other thing....UK mains run at 50hz will that have an impact, I'm suspecting not but just thought I would put it out there.........

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