Remember the motor runs on split or dual supplies (pos and neg). As you have a bench supply all you need do is disconnect the speed control input pin to the motor and connect it via a resistor (for the motors safety... the hall effect control logic) to your power supply. Connect the negative of your power supply to the grounds somewhere such as the phono sockets. Then power the player up, confirm the supplies are correct and slowly increase your PSU voltage. The motor should run and speed should vary.
The manual shows around 1 volt as the running value for the control input pin.
The manual shows around 1 volt as the running value for the control input pin.
Done as said.
Here's some current readings from my bench ps.
5V 0.001A 6V 0.003A 7V and onwards to 10V at 0.005A.
The motor remains stationary throughout. I wonder if whatever's stepping the motor's cooked. Theres a chip and 4 other IC compoents that might be at fault? I don't have data at all for those components though. The manual doesn't seem to cover them.
Cheers
Here's some current readings from my bench ps.
5V 0.001A 6V 0.003A 7V and onwards to 10V at 0.005A.
The motor remains stationary throughout. I wonder if whatever's stepping the motor's cooked. Theres a chip and 4 other IC compoents that might be at fault? I don't have data at all for those components though. The manual doesn't seem to cover them.
Cheers
OK... well typically failure items would be any small electroylitics, particularly any coupling to the motor coils. As you say, the circuit only shows the block diagram. Also the motor drive transistors. I'm guessing they are a "tab" type and soldered direct to the PCB. Its also not unknown (speaking generally and not specific to the Sony) for the magnetic hall sensors to pack up. They would be a problem to replace and find equivalents for.
Small electroylitics would be suspects. Resistors unlikely. Transistors are a definite possibility. If they are tab soldered I can tell you they are an absolute %&**" to remove because the base soaks the heat instantly. Far better (assuming this is what they are) is to lift the two legs and do cold checks with a DVM. If they pass a leakage test and read OK forward biased through the junctions then they are 99% sure to be good... and I think you have four of them to compare with.
Got them off ok. All seem to check out ok. There's 2 npn and 2 pnp. The analyser didn't find a component first time round on one of them so I've marked it and will probably replace it anyway. I might document this board for others use. There's a JRC 4558DF on there too. I'll check the caps next.
Hmm I'm short on answers really. I've put the player back together for now as I've been on the go about a week with it and need the space back. They weren't tab soldered, just older style types that can be heatsink mounted.
I tried bending the hall effect sensors a little closer to the magnet which seems to have improved the twitch a little but not really close to what I'd call starting to work.
I tried bending the hall effect sensors a little closer to the magnet which seems to have improved the twitch a little but not really close to what I'd call starting to work.
Yeah, I think I'll struggle to find them. It might be a case of using this player for spares and parting it out. I have bought another on everyone's favourite auction site which is working. I wonder if parting it out would cover the cost there or if the demands really that great though. Part of me wants to go crazy and use an arduino and a pair of newer h.e sensors to get it playing again. Kind of sad that it's not repairable. As a last move, I'll bend those sensors a bit closer and see if anything happens. Moving them the bit I did has increased the gain slightly.
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