V-5250
Toshiba 1978
Betamax V-5250



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Technical

V-5250 rear view
Rear view
Because of its age spares are not easy to obtain for the V-5250.

Modification for 60Hz, 120V mains operation

The following modification was designed to work on the SL-8000 and has not been tested on this clone.

Also, please note that for 60Hz, 200-240V operation, carry out steps 3 to 5 only.

Procedure

  1. Set the voltage selector to 127V.
  2. Remove and tie back the yellow and white wires from the power transformer T9501 which are soldered to the FS-1 board. Connect 2 leads to the terminals left free on the FS-1 board. The lead soldered to F9002 should be connected to Pin 4 of the voltage selector and the other lead should be connected to Pin 3.
  3. Reduce the value of the motor capacitor C8102 from 3.7 microF to 2.5 microF by removing the jumper lead from the PE-1 board.
  4. Remove D3101 from the PT-1 board.
  5. The following pulleys should be changed:

     FormerNew
    Motor pulley assemblyX-3656-025-l/5X-3656-350-l/7
     Select for correct drum free speed
    Drum pulley3-656-034-003-656-421-00
    Capstan pulley3-646-192-01/513-646-194-01/5l
     Select for correct tape speed

Thanks to Martin Imber for providing this information

Fault and repair guide

Tape transport is sluggish or fails to rewind

Internally the V-5250 contains many drive belts which are used in the mechanics of tape transport. With age these belts become slack causing malfunctions and when this happens the whole lot should be replaced. In particular for the rewind function you will need to replace a tyre on the supply reel.

Strange behaviour of capstan/drum servo

The first thing to check is the tantalum capacitors in the servo circuit.

Sluggish threading and capstan problems

The bottom bearing on the capstan motor is prone to wear and because this motor also drives the threading mechanism threading can become sluggish. When this happens you will hear a horrible squeaking noise!

Loading problems

To make the machine load properly, increase the tension on a spring on the lower sector assembly by shortening it so that a set of gears properly contact the drive tyre.

Quick fault guide

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FaultSolution
Colour streaking on playback of pre-recorded tapesCheck for poor contacts or contamination of the presets in the chroma circuit. If necessary clean and re-align.
Crackling or noise on soundSuspect failure of the record/playback switch S601.
Intermittently stopping when warmCheck the plug and socket connectors to the end sensor coil. Then check presets RV701 and RV702.
Interference on pictureSuspect failure of the record/playback switch S101.
No PowerMain on/off switch
Tape jammed or lock upStop solenoid switch
Ejects TapeDry Joint on tape slack sensor
No AC motor drivebad connections on 3 pin connector or AC motor open circuit
Picture slips in pauseBelts and/or brakes
Shuts down on PlayStatic build-up on metal threading guide, earth guide
No GoBoard SY-1: Q701 & 702 2SC-1364, auto stop
No play or spoolBoard SY-1: IC 701 CX-141
No PauseSY-1: IC 702, 703 TC-4001
Tape Lock Up or Spool malfunctionsSY-1: RV701, 702 22k pots sensor osc.
Tape lock -upSY-1 C701 .0033uf
Rewind onlySY-1 CN 6161--wire direct
No ctl pulse on PauseIC 501 CX-138
No trackingIC 502 CX-139
No revSY-11 change R1, C1 to 180k, .001uf, dirty contact cn4007
no audio recAS-1 Q605, 606
No buttons will lockbelts off
Rewind button will not stay downcheck board connections on supply sensor board
Intermittent colour on playCheck AFC adjustment on Y/CE board RV14 bottom pcb
White streaks, b&w and possible vertical jitterOne head clogged, dirty contacts on S101 or faulty pre-amp
Throws loop off tape when going from rewind to stopReplace or adjust supply/take-up of brake assembly
Auto stop when rew pressedCheck TP702 fro 3V p-to-p