Some progress with my PDP-11/73 system

[Allison]

>
>Subject: Re: Some progress with my PDP-11/73 system
>   From: David Betz <dbetz at xlisper.com>
>   Date: Mon, 09 Apr 2007 15:44:04 -0400
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>>> utility on the XXDP disk. I took all of the defaults and got the  
>>> following failure. Does this indicate that my RQDX3 controller is  
>>> bad or is this likely to indicate a bad hard drive?
>>
>> Since the controller handles the RX50 OK, almost all of it must be  
>> working.  If the LED on the RQDX3 goes out a few seconds after  
>> resetting, with the RD54 disconnected, the RQDX3 has passed its  
>> self-test.  From the error, I'd say possibly the RD54 has never  
>> been formatted on an RQDX3, or more likely something is wrong with  
>> the jumpers or connections.
>>
>> Double check that the drive select jumper is correct (normally it  
>> should be DS3; does the drive's LED flash when you run ZRQC?), that  
>> the little control board in the front of your BA23/BA123 with the  
>> READY and WRT PROT buttons is properly connected and those switches  
>> are set correctly, and that the cables from the distribution panel  
>> are connected correctly (with both the RD54 cables connected to the  
>> lower-numbered port).  It's just possible you have too old a  
>> version of the firmware on the RQDX3 (what are the EPROM numbers?)  
>> or that its jumpers (eg W23) are set wrongly, but this is less  
>> likely I think.
>
>You were right about needing to switch drive select to 3. That made  
>it possible to format the RD54 drive. It formatted successfully with  
>40 bad LBNs and 7 retired. I also tried formatting my five RD53s and  
>one formatted successfully with 27 bad LBNs. The other four failed to  
>even be detected as far as I can tell. Is there any point in playing  
>with these or would I be better off just trashing them?

I'd explore swapping boards or rechecking jumpers first, the try  ZRQC?
again. RD53s tend to have spindown disorder, spin up then spindown.
If they do that generally there is a fix.  If they spin up and you can 
hear the head mech load then something else likely on the boards is 
bad or wrong.


>Also, how bad are 27-40 bad LBNs? I know that they can be mapped out  
>but is this a sign that the drive is dying?

Thats common for MFM drives and the OS or controller will manage 
it usually.  However, if you see an increasing number of bad LBNs
or they are all on one head that can be an indicator of impending 
failure.


Allison