Teac a-7030 Dummy Plug

[Catnick]

even with the plug in place, its quite possible all the grease on the mechanism has turned to wax over the years locking the transport in place. Have you tried to fast wind the deck in either direction. Play mode may not work until you remove the front panel, clean the old grease that has turned to wax over the years and relube.

Thank you, you are the second to say the same thing, obviously this wasn’t tested by the seller before I bought the deck. At some point I’ll have to open it up, and then I’ll see how it goes. At least I have a copy of the service manual…
Thanks again.

 

[dankik]

It might be obvious, but did you check the fuse?
Does the power light come on and do the VU meters light up?

 

[Catnick]

It might be obvious, but did you check the fuse?
Does the power light come on and do the VU meters light up?

Power light is good, VU’s move up to halfway, then settle down. All lights look good.
I held the tension arm up to test the controls. The solenoids click on for rr/ff/play, the click off when I release the arm. I also laboriously threaded a tape (not easy with the brakes on!) and it seemed all good but the reels won’t turn. The fan and everything else also seem fine.
The only other thing I can think of is that maybe the dummy plug is bad, or not making a connection. I’ve tried everything while holding the plug firmly in place.

 

[rojoknox]

Greetings from RojoLand!

You have a dummy plug — but is it the correct one? Plugs for different Teac machines sometimes have different jumper connections. Per the A-7030GSL manual (should be the same for a non-GSL machine), the two jumpers are on pins 1-11 and pins 8-9 (and the two jumpers do not connect to each other!).

Take care,
—
J. E. Knox "The Victor Freak"

 

[Catnick]

Hi J. E., thanks for this. It is likely that the dummy plug is wrong. When the deck was delivered the dummy plug was loose in the box, so maybe it was a throw-in.
I see no jumpers on the plug, but when I look at the service manual, the notes are for SL models. Mine is a 7030 with no trailing letters (SL or GSL).

 

[mcgjohn]

Thank you, you are the second to say the same thing, obviously this wasn’t tested by the seller before I bought the deck. At some point I’ll have to open it up, and then I’ll see how it goes. At least I have a copy of the service manual…
Thanks again.

NP, its not rocket science. If you decide to tackle it yourself just take your time and go slowly. Lots of folks here have done the same. Don't forget these decks are 50+ years old so do need some sort of maintenance which likely has never been done. Take lots of pictures you can refer to later, label and plastic bag all screws as to where they go. Do one section at a time.

 

[Catnick]

Yes, slow and steady it will be.
I really appreciate all the folks out there who, like you, are generous with their time and ideas.
Thanks!

 

[dankik]

the two jumpers are on pins 1-11 and pins 8-9 (and the two jumpers do not connect to each other!).

Here is what @rojoknox is saying:

• You probably will not "see" physical jumpers on the plug since they are internally wired
• With the plug removed from the deck do the following:
• If you have an Ohm meter or DMM you can check the continuity between pins on the plug
• As @rojonox said, if you set your DMM to continuity and put one lead on pin 1 and touch the other lead to each of the remaining pins, you should only get continuity on pin 11 and open on all others
• Likewise, if you put one lead on pin 8 and touch all of the other pins, you should only measure continuity on pin 9 and open on all others

 

[Catnick]

Here is what @rojoknox is saying:

• You probably will not "see" physical jumpers on the plug since they are internally wired
• With the plug removed from the deck do the following:
• If you have an Ohm meter or DMM you can check the continuity between pins on the plug
• As @rojonox said, if you set your DMM to continuity and put one lead on pin 1 and touch the other lead to each of the remaining pins, you should only get continuity on pin 11 and open on all others
• Likewise, if you put one lead on pin 8 and touch all of the other pins, you should only measure continuity on pin 9 and open on all others

Thanks, dankik, @rojonox. I have tried wiring jumpers to the plug to test, but no luck. I have no test tools, DMM, etc. (I’m no techician.) The dummy plug Alexandre provided with the deck isn’t Teac, it’s Tokai, so I haven’t any idea what those jumpers are.
I then tried the dummy plug from my A-3300SX, but the pins seem too short.

So does anyone have a line on a “proper” dummy plug for the 7030? I won’t know if that’s the cause of the reel locks staying on until the plug’s resolved (I think).
Much appreciated as always.

 

[dankik]

Here is a video that you could try to see if the plug will work.
One more thing, make sure that the voltage selector is set to your correct AC input voltage (are you in the US or elsewhere)?
CAUTION: Looking at the schematic, it looks like there will be 100V on pin 1 of the socket. Turn power off while putting in the jumper wire and do not touch either end of the wire with power on.
TEAC 2300 3300 4300 6300 Reel to Reel DIY Dummy Plug Replacement

 

[Catnick]

Here is a video that you could try to see if the plug will work.
One more thing, make sure that the voltage selector is set to your correct AC input voltage (are you in the US or elsewhere)?
CAUTION: Looking at the schematic, it looks like there will be 100V on pin 1 of the socket. Turn power off while putting in the jumper wire and do not touch either end of the wire with power on.
TEAC 2300 3300 4300 6300 Reel to Reel DIY Dummy Plug Replacement

View attachment 3307641

View attachment 3307643

Oh my, thank you! I retired to Crete, Greece, so I set the machine to 240/50. As for the rest, it is beyond my means to check the sockets. I think I will need to ship the deck to Athens (€260 round trip just for shipping) for diagnosis and repair.

I really appreciate all the responses, but I thought I bought what was described as a “Very Good” condition machine. Live and learn (and spend).

 

[dankik]

Here is a diagram of the reel brake drums, brakes, and brake solenoid (from the SM). With the tension arm lever up and pressing PLAY, the solenoid should click and move the brake arms (red) to release the brake pads on the brake drums. There might be some minimal tension on the brakes to keep the tape from spooling out of the reels, but it should be light. With the back cover off, see if the solenoid moves between STOP and PLAY modes... also does it release when POWER is OFF?

Also, with power off and unplugged, you can try to rotate the BRAKE DRUMs by hand to maybe break (no pun intended) any adhesion to the brake shoes to the drums due to age and non-use. A SOLENOID works like an electro-magnet. There is a wire coil wound on a core that forms an electro-magnet when a voltage is applied that will pull any piece of metal into the center of the magnet (the plunger will be pulled in). When the voltage is removed, the magnetic coil will release the plunger and the spring will pull it back out of the coil.

It looks like the metal "arm" pivots about the screw near the center of the arm. When the solenoid pulls-in, it lifts the connected arm up which lowers the other side of the arm connected to the brake shoe down - releasing tension on the drum.

So if the drums are not releasing, it could be because (1) the solenoid is not pulling-in when in PLAY, (2) the lever arms are not moving because of old grease or corrosion on the pivot screw, or (3) the brake shoe is stuck to the brake drums due to age. Try and work them loose.

CAUTION: Keep your fingers away from the terminals of the capacitors near the brake mechanism. They are marked C10, C11, C2, C4, C12 in the photo below. They could hold an electrical charge even when power is off.

Here's a diagram of the tape mechanism. I have highlighted the solenoid in yellow, brakes in red, and springs in green.
Again, with power off and AC unplugged, try to move the brakes, solenoid arms and check to make sure the springs are attached as shown. Maybe the solenoid plunger or lever arms are stuck in-place due to hardened grease. Just try to get them to move a bit, then work them a bit to see if it will partially work.

 

[Catnick]

Here is a diagram of the reel brake drums, brakes, and brake solenoid (from the SM). With the tension arm lever up and pressing PLAY, the solenoid should click and move the brake arms (red) to release the brake pads on the brake drums. There might be some minimal tension on the brakes to keep the tape from spooling out of the reels, but it should be light. With the back cover off, see if the solenoid moves between STOP and PLAY modes... also does it release when POWER is OFF?

Also, with power off and unplugged, you can try to rotate the BRAKE DRUMs by hand to maybe break (no pun intended) any adhesion to the brake shoes to the drums due to age and non-use. A SOLENOID works like an electro-magnet. There is a wire coil wound on a core that forms an electro-magnet when a voltage is applied that will pull any piece of metal into the center of the magnet (the plunger will be pulled in). When the voltage is removed, the magnetic coil will release the plunger and the spring will pull it back out of the coil.

It looks like the metal "arm" pivots about the screw near the center of the arm. When the solenoid pulls-in, it lifts the connected arm up which lowers the other side of the arm connected to the brake shoe down - releasing tension on the drum.

So if the drums are not releasing, it could be because (1) the solenoid is not pulling-in when in PLAY, (2) the lever arms are not moving because of old grease or corrosion on the pivot screw, or (3) the brake shoe is stuck to the brake drums due to age. Try and work them loose.

CAUTION: Keep your fingers away from the terminals of the capacitors near the brake mechanism. They are marked C10, C11, C2, C4, C12 in the photo below. They could hold an electrical charge even when power is off.
View attachment 3308177
Here's a diagram of the tape mechanism. I have highlighted the solenoid in yellow, brakes in red, and springs in green.
Again, with power off and AC unplugged, try to move the brakes, solenoid arms and check to make sure the springs are attached as shown. Maybe the solenoid plunger or lever arms are stuck in-place due to hardened grease. Just try to get them to move a bit, then work them a bit to see if it will partially work.

View attachment 3308178

Hi dankik. I took a video of me running through the tests you suggest, but ios 18 no longer allows viewing or attaching videos.
But everything seems right with the machine. Capstan/pinch roller, meters, fan, etc. Here I am nearly a month after delivery and still trying to get a “Very Good” condition machine working.
I sure appreciate your help.

 

[Catnick]

Hi dankik. I took a video of me running through the tests you suggest, but ios 18 no longer allows viewing or attaching videos.
But everything seems right with the machine. Capstan/pinch roller, meters, fan, etc. Here I am nearly a month after delivery and still trying to get a “Very Good” condition machine working.
I sure appreciate your help.

By the way, the brake assembly looks good to me, the brakes actually lift off the reels but still no reel movement. Both upper and lower spring assemblies function fine.

 

[dankik]

I found this video of repairing the brake lever mechanism in a A-7010. Do your lever arms move up/down if you move them with your finger to release the brakes or does it bind? If they are releasing the brakes OK and the pads are NOT gripping the brake drum when power is off, then you might have dried lubricant on the reel spindles. Can you spin the brake drums like he does in the video? Did they move OK before you changed the belts, or is this a recent problem?

Watch this video:
Repairing Sticky Brakes On The Teac A-7010GSL

If it's not the brakes or brake drum (red), then it might be the motor bearing is frozen (blue), or the turntable mount (yellow) is binding on the case or something preventing it from turning. When the brakes are off, try to spin the brake drum.

From the SM. I don't know if the motors have a lube fill tube or not.

See if you can find some oil tubes similar to the ones in this illustration for the reel motors.

 

[Catnick]

Right off the bat, thanks so much for the help, videos, etc. i feel there is a good team of people rooting for the success of this project. I bought this machine from Canada a month ago, it was sold as “Very Good” condition; obviously not accurate. I have found a shop in Athens (I retired to Crete) and I’ll send it off for repair.
I’m a guy who loves these decks, but like I am with cars, just ‘cause I can drive them doesn’t make me a mechanic. Not sure how Alexandre tested this, but since I got 50% of price refunded I’ll just get it fixed.
So many thanks to you very generous hints. This is a great community.

 

[dankik]

Glad to help. Good luck with the repair. Keep us posted on the success!