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Hi:Does anyone have a copy of the schematics for the Philips CDM4/57?
I have a BC9500. It has the Philips CDM4 mech with a brushed DC motor. The transport stopped working. I found a charred resistor but cannot read its value.
The copy of the service manual that I have details the CDM4/33 which has a hall effect motor.
Thanks,
Derek
10 Ohms fusible.Two of them - one either side of the two related transistors.And replace the two transistors too. Note what's fitted and replace accordingly. Trust that rather than the manual, which has a serious typo there.
Martin
Martin:Thanks as always!
Hi Martin:
Would you mind confirming that TR 6124 is a BC338 and TR 6125 is BC328?
The print has faded and is difficult for me to read.
If so those seem to be obsolete. Can we use BC337 and BC327?
6124 is nearest to the connectors.
Yes, I'm sure they will be fine.
Hi Martin:Replaced the 2 transistors and fusible resistors. The fusible resistors burn up on power.
6124 is NPN?
6125 is PNP?
I checked the old transistors on the multimeter and they measure fine... no shorts.
Try running the motor off an external DC source.
The motor runs on a 5V power supply.
Do you have the schematics to share here?I cannot seem to find that exact version.
Hi Martin:I don't. The version on beoworld.com shows only the hall effect version of the transport which is a CDM 4/33.
Can you measure the current consumption of the motor when powered by external supply?It should only be 50-60mA.
The fusible resistors are there to protect the internal supply if the motor shorts.The later Beocenters employed small dc disc motors that can indeed short out or draw too much current.
You may need to look for a salvaged mech,as the motor is tricky to replace.The turntable is glued on to the shaft,and it's height is critical.
Nick
Thanks Nick.
This is helpful. What would cause the DC motor to draw more current than normal? Lack of lubrication? Do the bearings go easily on those things?
I wish I could drop in a CDM 4/33, the hall effect mech. The problem is I'd have to swap out the decoder board too as it is mech specific.
I can probably find a motor replacement (they use to sell them at parts express) but how would you remove the spindle from the mech without destroying the housing?
auric: What would cause the DC motor to draw more current than normal? Lack of lubrication? Do the bearings go easily on those things?
What would cause the DC motor to draw more current than normal? Lack of lubrication? Do the bearings go easily on those things?
Bearings and lubrication, yes.But also micro-tiny debris from wear to the brushes settling between the commutator contacts, gradually shorting them.
You need to remove the disc turntable to access the securing screws for the motor.If you can get another motor (check the label on it,they are not all the same!)you may be able to heat the turntable,and gently ease it off the spindle.Try and measure/record the distance between the turntable and the chassis before removal,as if you are successful in replacing the motor,you will need to get the height of the turntable to the same distance,otherwise there will be focusing problems.