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Actually what you are observing is the 8002 going into protection mode and locking out all functions. This can be caused by several faults:
1. Failed Carriage Tachometer / Optical Encoder (Most Common)
The tangential carriage drive spindle relies on an optical tachometer (an IR LED and dual photodiode assembly reading a slotted disk) to tell the CPU that the carriage is actively turning.
The Failure: The original IR emitter LED (OPE1 on the board) frequently goes open-circuit over time.
The Result: The carriage starts moving, but because the CPU receives zero “slide tacho” pulses from the sensor, it assumes the transport mechanism is jammed and cuts power to the carriage motor to protect it, freezing control inputs.
Fix: Replacing the IR emitter diode (a common modern replacement is the Optek OP240 or equivalent) on the spindle encoder PCB.
2. Servo Belt Slippage or Mechanical Binding
If the electronic sensor is fine, the carriage may simply not be moving smoothly.
The Failure: Old grease on the threaded lead screw and guide rails hardens, or the small rubber servo drive belt has stretched/perished.
The Result: The motor turns or slips on the belt, the carriage stalls mid-track, and the missing optical pulses trigger the same 2-second safety timeout.
Fix: Clean off old oxidized grease from the threaded shaft with isopropyl alcohol, re-lubricate with fine synthetic oil/grease, and replace the carriage servo belt with a fresh, correctly sized belt.
3. LDR / Aperture Sensor Drift in the Control Panel
The manual transport buttons (<< / >>) work by moving a mechanical light aperture between a small bulb and photoresistors (LDRs).
The Failure: If the photoresistors age or the calibration adjustment screws in the control assembly drift, the resting voltage fed to the control op-amp rises above the threshold (resting target is ~0.61V).
The Result: The CPU gets confused by the unexpected voltage rise during automated movement and halts the carriage drive.
Fix: Re-calibrating the aperture adjustment screws on the control board according to the Beogram 8002 service manual procedures.
4. CPU Board Solder Joints & Power Supply Capacitors
The Failure: Cold solder joints around the microprocessor socket, edge connectors, or dried-out electrolytic capacitors on the main board causing supply voltage ripple.
Fix: Inspecting the main board for cracked solder joints and performing a standard capacitor refresh if the deck is still running on original 1980s components.
Ok….received 2 cartridges in the post, fitted one and balanced the tone arm to neutral then set it to 1.0 gram. With the platter drive connections unplugged I hit play….tone arm moved to the correct position and dropped…however the carriage refused to move forward when nudged inward…hit stop and the tone arm moved back to rest.
My view is that the tracking sensor lamp (like the << and >> manual operators) and possibly the LDR too has passed its/their best, tried again and this time measured the voltage to the lamp 14.68vdc…so good, concentrated on the adjustment screw and had some success….after several adjustments managed to get the unit to play over halfway through an album at which point it decided to stop and return to rest…did this a couple of times despite a number of attempts at adjusting the shutter….looks like everything else is functioning correctly however the lamp and as it will be exposed the LDR too will need replacing….the carriage isn’t moving forward every 2 or 3 rotations of the platter but will move forward after around 9 0r 10 rotations…clearly not good.
Starting to give the main PCB a looking at and I’ve noticed C4 in the tracking circuit has a value of 47uf as opposed to the prescribed 0.47uf. The manual and the capacitor kit from martin both identify o.47uf, to be honest I’m not sure exactly what effect this will be having….but its coming out.
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