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Beogram 4000 Type 5215 - dial lights issue [solved]

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Velvet
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Velvet posted on Mon, Dec 3 2018 8:16 AM

Hello,

 first post here in this wonderful forum. I started recapping and fine-tuning my BG4000. This beauty came from UK (I live in Italy) around 2005 in terrible conditions because of a bad packaging. Luckily nothing was broken but many parts were disassembled including the arm mechanism. I was able to put everything in place and let it work for many years since then.

But at a certain point it began to develop strange issues: self power-on, 7" not recognized and other little gremlins. Ok, time for a total recap and a tuning following service manual.

Recapping was done with Vishay, Panasonic and Nichicon electrolytics. One of the main unipolar caps was shorted and others were out of specs. Tantalum were OK but I replaced with electrolitycs. Now the motor spins fine and quiet, sine-wave is clean both at 33 and 45 rpm at 6,2Volts (@33), no more self-power on.

 

But I have a new issue: the two dial scale lights self-power on when I plug the beogram to mains. They're always on, even if I press OFF . Other functions are correct (strobe light, motor, arm transport power On and OFF). 

Any suggestions or ideas will be much appreciated..

 


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Craig
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Craig replied on Mon, Dec 3 2018 9:46 AM

Hi

I am currently going through this exercise and I'm pretty sure I have the same problem....I have discovered that the reed relay 2MS2 24vdc contact is permanently on the closed condition, therefore illuminating the scale lamps on power up, they should only illuminate when the relay coil is energised. It looks like the only solution is to replace the reed relay, this will be very tricky as the relay coils are very delicate...the connecting wires are hair thin and graet care will be needed...you, and I, will also need to source a replacement reed switch of the correct size, wattage and Normally Open (I think) shelf condition......good luck, and post pics ;¬)

Dillen
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Dillen replied on Mon, Dec 3 2018 10:06 AM

Quite common to see the contacts welded (or magnetized) together.

Leave the coil in circuit and pull out the reed element (glass tube with contacts).
It can be replaced separately. Just find a suitable size.

Martin

Velvet
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Velvet replied on Mon, Dec 3 2018 10:27 AM

OMG that sounds a difficult challenge... I will take some measures around the relay this evening. I guess there are no direct interchangeable parts on the market today :-(

 

Craig
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Craig replied on Mon, Dec 3 2018 10:53 AM

Martin

Thanks for the tip.....I was going to remove the whole thing but will take a closer look now, can you take a look at this, I'm not sure what is meant by 15=20AT is it the magnetic field required to actuate the switch?

https://www.ebay.co.uk/itm/KSK-21-Reed-relay-Pswitch50W-Contacts-SPST-NO-500mA-max350V-KSK-1A52-1520/202412891200?hash=item2f20bf9c40:g:TmYAAOSwyGhbfuzB:rk:55:pf:0

Regards Craig

Craig
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Craig replied on Mon, Dec 3 2018 12:48 PM

Got it......

AT means Ampere-Turns and is a standard unit categorizing the magnetic sensitivity of Reed Switches. The AT value is measured by centering the Reed Switch in a standard coil, to which an increasing current is applied. At a certain current (Amps) the Reed Switch closes by means of the magnetic field generated by the coil. This is the Operate (or Pull In) value, calculated as Amps x number of coil turns = AT. Reducing the current passing through the coil until the switch reopens, the Release (or Drop Out) value can be obtained.

Velvet
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Great! But i guess the original switches AT is unknown...or not?

 

 

Velvet
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Great! But i guess the original switches AT is unknown...or not?

 

 

Dillen
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Find some in the correct physical diameter to fit inside the coil.
Don't worry too much about the magnetic parameters. The old switches weren't that sensitive and the coils therefore quite powerful.
If a reed relay won't switch correctly, try rotating it a bit.

Martin

Velvet
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Thanks Dillen.

I took some measures around the relays, both in stand-by and On. Please see pic. 

 

Velvet
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Velvet
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Velvet replied on Mon, Dec 3 2018 11:06 PM

I did a test. Cut the red +24V wire from the reed "always on" switch and temporarily connected with the +24 grey wire on the other working relay: everything fine, lamps off when TT is in standby and lamps ON together with motor, strobe and arm pressing ON.

I ordered some new 2x14 mm glass reed contacts hoping they will fit and work. Many thanks to Martin who provided the possible solution.

 

I will update the post when the switches will arrive.

Dillen
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Dillen replied on Tue, Dec 4 2018 11:22 AM

Actually, I think Craig was ahead of me with 20 minutes or so. Laughing

Martin

Velvet
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Velvet replied on Tue, Dec 4 2018 11:52 AM

Yeah, sorry Craig..

 

But you saved both of us Martin, we didn't know the Reed tubes are replaceable Smile It will be a late night, keep-calm affair (those tiny coil wires are so close to the tubes soldering points..) but let's give a try.

Velvet
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Velvet replied on Tue, Dec 11 2018 10:18 PM

Hello again,

 

reed switches arrived and carefully fitted in the relays. Everything fine, now the BG shuts off and powers on how it should. Thanks. 

Another couple of issues to solve, the main is 7" records not recognised. I will search across the forum before asking your help again.

Old reeds removed:

New reeds in place:

TT spinning again:

 

 

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