Dual 731Q Repair

[Thug horse]

Hello,

Been a lurker around this forum for a short time and I have to say it is an amazing resource! I've been hunting for a good TT for a few months now and came across a Dual 731q at a thrift store this afternoon. After getting the guy home I found that the unit will not "turn on" once plugged in . That is, there is no strobe light, platter spinning, etc, although the tonearm seems to move properly. I figure that most probably I should check/replace the fuse, however I can't seem to figure out how to get the unit open!

I've been through the manual a few times, which seems to suggest that I need to: 1)disengage the three transport screws and 2) unscrew the mounting plate. I think I've got the transport screws disengaged (they are unscrewed and are able to move at an angle) however I am less sure about the mounting plate. Is this the area where the signal and power cables come out of? If so, I've unscrewed this plate but the turntable it self will not come out of the housing.

Would anyone be able to explain the process for removing this direct-drive table? Also, any helpful tips for getting the unit back to working condition again? Thanks for taking the time to check out my post! I really appreciate it.

[Hugues TR4]

Have a look at the first thread/sticky on this section ("frequently asked questions") and you will find an answer to your problem, how to lift the TT out of its plinth. Sometimes it requires a little bit of patience...
As for direct drive, my skill is very limited as I owe an idler drive 1019.
Hoping one of our fellow dualists can help you further...
Good luck,

Cheers,

Hugh.

[Thug horse]

Thank you for the suggestion! I had already checked out the sticky post but still couldn't manage to get the thing off. I think I've got the "travel screws" where they need to be, but there still appears to be something holding the table to the enclosure.

[Hugues TR4]

You are sure that they aren't any extra screws blocking the whole plate on the plinth for extra travel safety? (sometimes camouflaged by a little stopper)
Or maybe the leads (mains and amp) are set too tight or blocked underneath and prevent the plate to come out?
Just as a thought...

Cheers,

Hugh.

[kalypso]

The travelling screws must be loosened so you can move them up and down. In the down position, tilt them about 45 degrees to the outside of the unit. While doing this, press the chassis a bit down against the spring tension, this makes it easier. Once you've got them in this position, lift the chassis upwards. Do this with one screw after the other until you've got the whole chassis out of the plinth. Be careful not to damage any cable connections from the front panel to the chassis.

Sounds complicated, but it is very easy when you have done that once.

It is helpful to remove the 2 screws at the backside of the plinth, where the power and signal cables passthroughs are, this make it easier to take the chassis out of the plinth.

Its a good idea to remove the platter and the counterweight during this procedure to avoid damages. Lock the tonearm securely.

There are no "extra"-screws holding anything.

regards, kalypso

[Thug horse]

Thank you very much for your help! Your description helped immensely. I opened her up and fixed the power issues. Platter spins, strobe works, pitch mod works, great! However, I discovered new problems that may in fact have the same root.

First, the tonearm does not respond to the cue control switch. Flipping the switch does nothing to the arm and there is no resistance. Also the lift button does not work. Second, the stop button appears to do nothing, the only way to stop the platter is to manually move the tonearm back to the rest. The service manual seems to suggest that I take apart the cue control plate and reassemble it after a cleaning. It seems like this would not really fix this particular problem seeing as how there is no resistance when moving the cue switch - perhaps some catch is not catching. Finally, I found a loose screw and two washers inside of the housing once opened . What a bummer!

As it stands I think I am going to try to take apart the cue plate, but am very open to suggestions or tips from folks here. Thanks again for your help so far, I do not think I would have figured it out without you!

[kalypso]

The cue and stop buttons don't work direct in a mechanically manner, they operate magnetic switches. Usually a relativly loud "click"-noise appears when they are pushed. Do you hear anything when pushing them? If not, maybe the magnetic switches are dead and need to be replaced.

Anyways, congratulations that you've got the table up and running again. Its a great machine for sure!

regards, kalypso

[Thug horse]

Thanks!

There is no clicking noise when the cue switch is flipped, however I believe that the switch did work when I checked the unit out at the thrift store. Is it possible something came loose during transport?

[kalypso]

Maybe it has something to do with the screw and the washers you found. Are you sure that the cable connectors from the front panel to their destinations are all in place correctly?

[Thug horse]

I think the connections are in the right place. Also I believe the cuing feature should work without any power or buttons other than the cuing switch.

[kalypso]

The three buttons on the front panel are just switches and operate (noisy) pull magnets, the start button switches power on. Have a look at Fig. 17 and 18 in the service manual. Only the cueing lever right beside the tonearm works without power on.