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Old 2nd Dec 2022, 10:18 pm   #7
DMcMahon
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Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Truvox PD-95 R2R Check Out

Erase also does not work.

Play/record head windings appear good, 1049 Ohms / 867mH & 1056 Ohms / 860mH, have seen no data for these heads but think they must be OK.

While doing other tests fast rewind became erratic, previously it generally worked well with occasional failure to start but now it was failing to start regularly.

Decided to try and remove the chassis again from the wooden case and was successful on this second attempt. As expected, the reel motor (Garrard) shafts do couple direct to the reel tables so as long as the reel table brakes are removed (they are) then the reel tables should spin when the respective motor drives in fast wind.

With chassis out of case then easy to access the mains on lamp, it was black so looked blown, disconnecting one wire to isolate the transformer winding gave an open circuit reading across the lamp. Tried to remove the lamp from the lamp holder but impossible to remove, so cut off the holder and threw away. Used a 6 volt wired grain of wheat type lamp as replacement.

Removed the Take Up reel table in order to install a replacement tape counter belt (counter is driven from the take up reel table), was not easy to access the small hex head grub screw that locked the reel table to the motor shaft.

After searching through loads of drive belts could not find one long enough and small enough thickness to fit in counter pulley correctly. Tried a 1.9 x 120 but far too tight and stopped the Take Up table rotating in Play. Also tried a 2.5 x 145 but this also too tight and too fat really for the pulley.

Tried stretching a couple of other belts to try and make fit but they both broke during stretching, looks like will need to purchase a suitable belt.

The two 2uF motor run capacitors measured OK, 2002nF / 0.33 Ohm ESR & 20008nF / 0.16 Ohms ESR, did not voltage check them.

The 2 motor resistors measured OK, 3000 Ohm measured 2.97kOhm & 4000 Ohm measured 4.02kOhm

David
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