Messages

1

Reel to Reel Tape Machines / Re: Technics RS1500 Supply/take motor up problems

« on: March 08, 2012, 08:28:03 PM »

Found the problem late yesterday and fixed it.

The reel motor control boards, mounted on the left side of the machine as viewed from the rear had a DC power problem. The unit had been repaired some years ago and that repair required a trace to be jumped and another trace re soldered. This trace carried 15 volts to a part of to take up and supply reel control board had opened up where it had been re soldered.

The give away was the diodes in the  top and bottom of the board should read the same DC but did not. As i recall somewhtrere around 9 volts.
Diodes 701,703 and 7055 should read the same as Diodes 702, 704, 706
 
Thanks for of the great suggestions!!!

2

Reel to Reel Tape Machines / Re: Technics RS1500 Supply/take motor up problems

« on: February 27, 2012, 12:55:41 PM »

The auto shut off failure describes the problem. I will see what the manual says.

Manually turning the take up and supply reels in "Play" has no effect. The reel brakes release in the "play" mode and are free turning, not tension.

Went through the battery switch. That's a good call as the units "battery" operation requires 3 voltages.

Same with the timer.

I had a problem many years ago with excessive take up torque. Took the unit to Technics twice-they could not find the reason. Had a friend who was an excellent tech. He solved the problem in a day-the speed change switch. In his words, "Lots of stuff goes through that switch."

Cleaned the switch-still have the problem.

I will go back to the motor circuit board and re check all of the connectors. They have all been cleaned.

Visual inspection didn't reveal anything except dust. Checked supply voltages and the reel control voltages. Everything checked out in stop. Since the Fast Forward/Rewind would not operated, those voltages could not be verified.

Thanks!!!!

Don Worsham

3

Reel to Reel Tape Machines / Re: Technics RS1500 Supply/take motor up problems

« on: February 26, 2012, 03:36:51 PM »

Hi,

Thanks for the reply.

Tape path is clean. I often will rewind tapes outside of the head block with the to tape guide/rollers depressed far enough to close the sensors without any problems. However, the will not rewind or fast forward using this method.

The machine acts like it is not sensing anything in the tape path even when there is tape present and the capstan is turning.

The micro switch closures associated with the two tape tension/guide arms appear to be be operating properly. Either one will start the capstan.

My fear is that the has been a major failure in the logic board that controls the deck's play/rewind/fast forward operation.

All suggestions are welcomed.

Don Worsham

 

4

Reel to Reel Tape Machines / Technics RS1500 Supply/take motor up problems

« on: February 25, 2012, 08:34:48 PM »

My trusty 1500US will not longer play, fast forward or rewind. Capstan runs, speed select works. All of the power supply supply voltages are present.

Thread up a tape, press play: the pinch rollers pull in and contact tape, then release. The supply and take reels up do not turn.

Any ideas?

I have the service manual for the machine.

Don Worsham