• Please review our updated Terms and Rules here

TSZ07 repair advice needed - Error 54 - Motor Fault

T

Terry Kennedy

Experienced Member
Joined
Jul 7, 2017
Messages
241
Location
New York
I'm restoring a DEC TSZ07 (AKA Cipher M995S, I think). The company I got it from said that when they powered it on 10+ years ago, it displayed gibberish on the front panel display and then went dead. I disassembled and cleaned it and determined that they had let the magic blue smoke out of the power supply (quite badly - the PCB was completely warped where parts had burned up).

I sourced a replacement power supply and the drive now powers up and displays "TESTING" and "TESTPASS", and I can try to load a tape. It then reports "54 - MOTOR FAULT" during the load process - once the tape is wound onto the takeup hub, it seems like the supply motor tries to turn counterclockwise to take up the slack and that's when the fault happens.

The manual says that the troubleshooting steps are 3 - Turn it off and back on; 5 - Replace FRUs and 6 - Call DEC Field Service. The FRUs called out are 12 (supply motor) and 4 (servo circuit board).

Service Aid 111 (motor and servo tests) runs without error. Service Aid 525 (motor calibration) also runs without error and stores the updated calibration in the NVRAM.

Both hubs turn freely, with (as far as I can tell) equal resistance to being turned. There is a slight "tick" every 360 degrees on the supply hub, but if I'm remembering correctly from these many years ago, that's the linkage for the reel grabber jaws tapping on the actuator and not an optical encoder hitting something. Since the motor calibration procedure passes, I think the encoders are working properly.

Does anyone have any ideas about what to try next?
 
Have you verified the encoder wheel in the take-up reel tensioner spins freely? It's that spring loaded arm that presses against the reel. Both my units had a sticky bearing and had to be dismantled and cleaned before various take-up faults would clear.
 
NeXT said:
Have you verified the encoder wheel in the take-up reel tensioner spins freely? It's that spring loaded arm that presses against the reel. Both my units had a sticky bearing and had to be dismantled and cleaned before various take-up faults would clear.
Click to expand...
That was indeed stuck. I was able to get it to turn freely after gently rotating it a bit.

The first load I tried after freeing it up stuck in a state where "LOADING" was flashing, but the motors had gone limp and there was a little slack in the tape threaded through the drive. Subsequent tests are now returning "63 - Motor Fault". Any other ideas, or do you think I should disassemble and clean (and if so, how - is it covered in the DEC technical manual)?
 
There's a video I made on Youtube a few years back on how to remove the arm assembly from the drive and dismantle it down to the point where you can oil it. Don't have a link handy at the moment.
It is for an older model unit but it should be pretty much the same.
 
NeXT said:
There's a video I made on Youtube a few years back on how to remove the arm assembly from the drive and dismantle it down to the point where you can oil it. Don't have a link handy at the moment.
It is for an older model unit but it should be pretty much the same.
Click to expand...
Any hints for keywords or usernames to search with? The only Youtube video I found was: https://www.youtube.com/watch?v=8K3-1Tbr928
 
Hello,
I also have two TSZ07 drives.
I had to repair one motor, because it was not rotating as expected: there was a lot of friction inside when rotated by hands.
Long story short, permanent magnets detached from the external chassis, and touched the rotor.
I had to take off the motor from the drive chassis avoiding to damage the encoder wheel.
Then I disassembled the motor,removed old glue, then placed the magnets on the original position (old glue was a visible reference for it),
held in position and glued with abundant cyanoacrilate.
Then reassembled the motor and repeated calibration. Drive now works.
If your motors have no sign of strange friction or noises, probably they are fine.

You should check also the torsion balance measuring tape tension. It's a rotating cyclinder, just like a rubber roller but made of rigid plastic.
On the bottom side there are two thin wires coming out.

Andrea
 
Thanks to everyone for the advice. I've had to move the VAX 4000-200 and the TSZ07 into a storage room for now, as I have a bunch of large (44") Epson printers in for work. I'm then off to California for a few weeks, but when I get back I will start working on the TSZ07 again, and will likely have more questions.
 
silver said:
Are you the Terry Kennedy who used to attend the DECUS meetings? If so I haven't seen you since (roughly) 1990. I am Peter, the DECUS UK RSTS King.
Click to expand...
Yup, that's me. Remember when I showed you how to change your voice with helium from the party balloons?
 
You must log in or register to reply here.
Back
Top