Trouble with RL02.

[Bill Pechter]

Been a long time but I'm remembering that you could get something like that
if the RL11 cable was reversed... anyone remember if my memory's dropped 
too many bits.

Bill

Charles wrote:

>I'm trying to get my RL02 working with my 8/A. Thanks Tim R. for
>lending me a cable and terminator!
>
>After finding a cold solder joint at the 8.2 MHz oscillator on the
>RL8A, I thought I had it licked... the master clock would start
>and stop if I pressed the oscillator's case. Now there is a steady
>4.100136 MHz clock at the ribbon cable connector to the logic
>board inside the drive. The power supply voltages on the board are
>all within spec.
>
>The problem is that not only does the Fault light still stay on,
>the ready light (that illuminates the "Unit 0" plug) is also on.
>According to the manuals this is not supposed to be possible since
>the ready light only comes on when track 0 has been found, and the
>heads are still locked home :( ???
>
>The Load button has a very dim bulb, near end of life, but it does
>light after the slow 15-second disk rotation. Pushing the Load
>button does nothing (disk does not spin, Fault and Ready still
>lit). Examination of the state machine lines shows that it is in
>state 0 (Load Cart) but the input to it (DL5 ERR STATE COMD L) is
>also asserted.
>
>When turning the spindle by hand (from the access port underneath
>the drive, with a cartridge in place) I can get a signal of at
>most 0.2 volt p-p. This doesn't produce any pulses from pin 1 of
>the LM393 amplifier. If I ground the "Raw Sec Pls Return" then I
>can get a very noisy pulse train. When it's "inching" in startup
>mode it is maybe 10 mv p-p which is way below the spec in the
>manual and nothing comes out of the amp.
>
>Is this sensor hall-effect or is it just a coil? DEC went out of
>their way to run 5 volts to it, so I assume it's a transistorized
>unit? More importantly, anyone got a spare? :)
>
>thanks
>Charles
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