Trouble with RL02.
charlesmorris at direcway.com
Mon Nov 14 17:38:06 CST 2005
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
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? :)
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