Roland RE-201 bias oscillator's coil damaged? [SOLVED]

Hi,

I've my just bought 3 Roland RE-201s on the bench for restoration.
2 of them are nearly finished, they self-oscillate too etc.

But the 3rd have [at least] a problem.
I've tracked down it to the missing 60Khz signal outside of the bias oscillator circuit [-> pin 54 of the psupply board],
so the erase head do nothing.
On the working 201s, the 60 Khz signal at pin 54 is around 45V as per specs, on this one is around 700mV.

On the oscillator side of L23 coil, both working and defective 201 have around 2V at respectively [correct] 60Khz and [wrong] 72Khz,
exactly the same waveform on both units.

So, I'm pushing myself to assume that all the other components of the bias-oscillator are more or less ok and that its the coil the culprit.

I've measured with an ohmeter the resistance [onboard] of the external wiring of the coil, and the perhaps defective one
gives 13 Ohm instead of 2.6 Ohm of the one in the healty 201.

Part number is listed as MC-126-2133B on schematics, and in the units they're marked as 14S2133B.
I've not found their datasheet so far.

Someone have clues?

Thanks!

P.S. here is the schematic:
http://www.omegav.ntnu.no/~karlto/space_echo/page9.png

Ha-ha!
I was right!

One of the pins of the L23 went slightly off from the wire.. only a fraction of millimeter..
[I've increased the distance for the pic].





Soldered the wire..
now the 201 is working!

Hey, I've just got a RE-201 but the echo level is super low, reverb is fine, no self oscillation the intensity and echo volume controls do seem to work but the wet signal is barely audible with both at max, any ideas? Cheers.

i got the low level when my heads are dirty, just clean them with alcool.

Yeah cleaned the heads with alcohol. Hoping it's just a bad tape, but it's really darn low.

All my 3 201s self-oscillate, also with incredibly bad tapes [I've tried it]..

Before you dismantle the thing and do the measurements I did for identifying a circuit's culprit, try that:

Adjust the tensioning felt spring before the heads [on the opposite side of the pinch roller], and
be sure also that the roller tension isnt too low [there is an adjustement for that, under the deck], by watching at the tape, it shouldnt  slip..

Turns out the tape heads needed the finest of adjustments. Spent two or three hours tweaking the heads and now she sings like a bird with tourettes! Good times.