Hi I have a Pioneer PLX 500 turntable, (I will be looking at it for a friend) he tells me that the turntable won't start/run, this seems to be a known issue on the DJ forums, but their idea of a fix is to replace it.
Does anyone have any experience of the failure of these units, please?
Does anyone have any experience of the failure of these units, please?
If it doesn't revolve and there is power going in and the switch works okay then you have a problem with the 3 phase power supply to the motor it being servo controlled .
Now if a schematic is available do you have the technical ability and tools to repair it ?
Now if a schematic is available do you have the technical ability and tools to repair it ?
Hi Duncan, thank you for your interest. From the description of use by other owners of these TTs, it does seem that even light DJ use can led to the failure described, I suspect drive failure and in response to your specific points, sadly i do not have a schematic, if I had one it would certainly be easier to trace through the circuit, otherwise it is going to be a bit of a grind tracing out the circuit to see where the signal path stops.
I do have the capability to do this, but previous jobs have shown me that the effort required is often great and the reward small. Even to the point that on returning one repaired VCR player (a while ago) the ungrateful owner said "I was hoping you might not be able to repair it so that I could justify buying a new one!"
Because this does seem to be a common issue I have suggested that the owner discusses this with Pioneer with a view to sending it back to them for a replacement motor/drive unit, however, if Pioneer are not prepared to do this I was proposing to check for correct power supply rails to the key parts, operation of the on/off and stop/start controls, signals from the motor control chip and operation of the transistor output stages.
One of my worries is that the design seems to be weak and replacing like for like may result in repeat failure.
Im off to look for a schematic.
I do have the capability to do this, but previous jobs have shown me that the effort required is often great and the reward small. Even to the point that on returning one repaired VCR player (a while ago) the ungrateful owner said "I was hoping you might not be able to repair it so that I could justify buying a new one!"
Because this does seem to be a common issue I have suggested that the owner discusses this with Pioneer with a view to sending it back to them for a replacement motor/drive unit, however, if Pioneer are not prepared to do this I was proposing to check for correct power supply rails to the key parts, operation of the on/off and stop/start controls, signals from the motor control chip and operation of the transistor output stages.
One of my worries is that the design seems to be weak and replacing like for like may result in repeat failure.
Im off to look for a schematic.
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Even after reading the advertising literature I feel there is a lot of "hard sell " and that engineering wise its not worth the high amount of money, I was shocked to find how much the company wanted .
Of course that is my personal opinion but for that amount of money a good second hand genuine mid-range quality hi-fi record deck could be bought , its heavily pushed towards the DJ market but even the advertising admits its a "copy " --and that's putting it nicely -- of a much more higher quality deck of a different manufacturer .
I will have a look myself for a schematic but I wont be holding my breath.
Of course that is my personal opinion but for that amount of money a good second hand genuine mid-range quality hi-fi record deck could be bought , its heavily pushed towards the DJ market but even the advertising admits its a "copy " --and that's putting it nicely -- of a much more higher quality deck of a different manufacturer .
I will have a look myself for a schematic but I wont be holding my breath.
The service manual is available from VinylEngine (free registration reqd.).
Pioneer PLX-500 Direct Drive Turntable Manual | Vinyl Engine
Circuit diagrams are included, but little else.
Pioneer PLX-500 Direct Drive Turntable Manual | Vinyl Engine
Circuit diagrams are included, but little else.
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Thank you ralph, I spotted that just after my post, but thank you for posting, much appreciated.
Split power supplies look good and main motor driver, IC BA6868fm data-sheet is helpful too.
Split power supplies look good and main motor driver, IC BA6868fm data-sheet is helpful too.
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Hi Roog, did you manage to fix your PLX-500 turntable?
I got a devective one. BA6868fm had a short circuit on two of the motor coil's
output pins. I replaced the motor drive (BA6868).
I cannot measure any abnormalities now. However, it still doesn't spin.
I got a devective one. BA6868fm had a short circuit on two of the motor coil's
output pins. I replaced the motor drive (BA6868).
I cannot measure any abnormalities now. However, it still doesn't spin.
Hi again, solution was to replace the motordriver again. (bought 5 pcs at Aliexpress). The IC ist very heat sensitive. Take care when you solder! Now it works fine. By the way i removed the heat-tape between IC and haet-sink. I put additional long aluminium profile in between IC an heat-sink. Heat can be absorbt much better now!