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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 6th Jan 2010, 2:50 pm   #1
jimpink
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Default Philips GP200 cartridge

Hello,

I've just found an old 70s Philips portable record player and on inspection I've discovered that one channel is far stronger than the other. It's fitted with a GP200 cartridge so I swapped this for a GP204 which I had spare and the same problem occurred only this time it was the other channel.

Could this be that both cartridges have issues and I should therefore obtain a new one? Or does the unit itself have issues and may well need new transistors somewhere?

Thanks
Jim
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Old 6th Jan 2010, 3:16 pm   #2
geofy
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Post Re: Philips GP200 cartridge

Well both channels are working so it is unlikely there is anything wrong with the transistors, and silicon transistors seldom go wrong if they are used correctly. It could be that you have two faulty pickups, or the connection in the pickup arm could need cleaning. Are the controls such as balance set correctly.

Geof

Last edited by Dave Moll; 6th Jan 2010 at 7:11 pm. Reason: unnecessary quote removed
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Old 6th Jan 2010, 3:25 pm   #3
jimpink
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Default Re: Philips GP200 cartridge

Yes the balance is positioned correctly, I was using this to determine the fault.

How would I go about cleaning the connection in the pickup arm?

Thanks
Jim
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Old 6th Jan 2010, 6:43 pm   #4
geofy
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Post Re: Philips GP200 cartridge

The pickup arm probably has recessed connections, these might have become compressed and need pulling back out slightly, so a very small bladed blunt screwdriver could be tried, if the metal contacts are visible they shouldn't have any tarnish, again the blunt screwdriver can be used to polish the contacts without damaging the plating. The same goes for the four metal contacts on the back of the pickup head. And of course a squirt of Servicesol Super 10 switch cleaner wouldn't go amiss.

On the output side, make sure the speaker plugs and sockets are clean if they are the extension type. Also that the volume control is making good contact with no quiet spots.

Geof
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Old 6th Jan 2010, 7:30 pm   #5
jimpink
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Default Re: Philips GP200 cartridge

Ok I've checked and cleaned the connections on both the pickup head and arm but it hasn't changed anything. The volume is making good contact with no quiet spots.

It looks like I need a new cartridge but wanted to ask the forum before making the purchase as Musonic are asking for £40.

Could there be any other cause for these symptoms?
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Old 6th Jan 2010, 10:06 pm   #6
Michael Maurice
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Default Re: Philips GP200 cartridge

I would go for a new cartridge.
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Old 7th Jan 2010, 1:02 am   #7
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Default Re: Philips GP200 cartridge

I have worked on literally dozens of philips decks using these heads, and had roughly 60% of them duff. At present I'm working on restoring a few by adding new cartridges as 'guts' - watch this space for a how-to if I'm successful!
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Old 7th Jan 2010, 11:19 am   #8
geofy
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Post Re: Philips GP200 cartridge

Quote:
Originally Posted by ben View Post
At present I'm working on restoring a few by adding new cartridges as 'guts' - watch this space for a how-to if I'm successful!
That will be interesting to see what happens Ben, is the original a crystal type, could a ceramic pickup be grafted on, though the GP type pickups are the slimmer all in one plug in types. The amplifier could be checked in the meantime with the pickup head removed by touching the pickup arm contacts with the metal screwdriver, two of the contacts should give a buzzing sound if the channels are working.

Geof

Last edited by geofy; 7th Jan 2010 at 11:25 am.
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Old 7th Jan 2010, 2:05 pm   #9
jimpink
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Default Re: Philips GP200 cartridge

Ok then, looks like I'll be getting a new cartridge.

I just tried to check the amplifier as Geof suggested by touching the pickup arm contacts with a metal screwdriver but none of them gave a buzzing sound.

Both the arm and head have 5 contacts...

Thanks
Jim
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Old 8th Jan 2010, 1:33 pm   #10
geofy
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Post Re: Philips GP200 cartridge

The top middle connector and the two lower connectors are the screens and all joined together. The two upper connectors either side are the left and right channel input. For mono they are joined. If the arm doesn’t lift to far up try holding a mirror underneath the pickup and use a torch, the connecting wires should be visible, these are delicate so don’t move them, but check that the solder joints looks good. Touching the live contacts with the screwdriver should produce a click; touching the metal part with a finger usually makes a buzz, with the volume set around half way.

The connecting pins on the pickup should be clean, they can get tarnished. A knife blade lightly scrapped across can clean them, then a squirt of Servicesol 10. The stylus tip can be cleaned with a soft brush and a tiny drop of soapy water brushed in the forward direction of the stylus, never backwards.
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