Subject: Re: I'm starting a collection of TK50's
To: Douglas S. Meade <>
From: emanuel stiebler <>
List: port-vax
Date: 06/20/1999 09:18:28
-----Original Message-----
From: Douglas S. Meade <>
To: NetBSD "Port-VAX" Mailing List <>
Date: Saturday, June 19, 1999 9:41 PM
Subject: I'm starting a collection of TK50's

>I started my lift with my uVax II with no TK50, and now I have two,
>but apparently neither of them works.  The first came to me with
>a tape still in it, which was already a bad sign.  I inserted
>it into the bay, and connected it to the dangling cable of my
>TQK50 card, (and the power of course) turned the machine on, and I got:
>no green light, flashing red light.

Sounds nice ;-)) My first 3-4 of the TK50 drives were broken first ...

>I read some miscellaneous postings from this newsgroup, dejanews,
>and the nice little page at,
>and decided, yes I was brave.  So I opened up the tape drive, and saw
>that in fact the tape was wound up on the takeup reel pretty far, and
>apparently the drive didn't want to rewind it.

What i found (in my drives and on the Internet) are two MAIN failures:

1. The tacho for the speed control.
    In the left,back corner of your tape drive (Open the metal cover first,
left, back is meant with the open mouth in front of you ;-)) you see some
LEDs. Two of them simply checking if there is any tape in the drive, the
other two (one on the top, one on the bootom of the drive) checking the

2. A broken/old/uneven TAKE-UP LEADER.
    Check how it looks like, and probably replace it.
    (This is a $1 part, easy to get from DECPAQ. Order Number is:

>I removed the cage from this drive, and managed to get the tape
>completely out, but not rewound.

You can open the cartiges, and put the tape back in ;-))
I've done this some times, until all my drives worked again.

>My first question: I've worked with at least 3 TK50Z (SCSI) in the
>lunchbox size case, and they are all very dependable.  Are the
>uVax type TK50's more commonly bad, or am I just unlucky?

The Tk50 is in both cases (TK50 OR TK50Z) the same drives. The real problem
with them, that the drives are getting dirty ...

> (I seem to remember Brian Chase saying he had several of them,
> and they were all bad.

As I said, I had some broken too, and now, I have something about 5-7

>Second question: I've heard that the tape drive itself inside the
>TK50Z is actually the same


> But there is a SCSI card interfacing to the drive, to make it look
> like SCSI to the outside world.

Excatly. PLUS a big PCB with resistors to keep the power supply working ...

>If this is true, could I remove the drive from one of these
>boxes, and use it in the uVax?

You can do it, but i would try to clean the other drives first. You probably
need a SCSI tape drive again.

>Third question: Could the problem be the Vax itself, maybe not sending
>enough power to the drive or something?  I haven't tested these drives
>in other machines.

This drives don't need so much power. That's why the resistor pacj is in the
TK50Z BOX ;-))

Have fun,