AKAI GX-747 BELT DIMENSIONS ?

[marrscommunications]

4-23-12,

Hello, I have the GX-747 Tensioner Belts In Stock, but cannot

Cross over the Other 2 Part Numbers. ( MB-331022, MB-330938 ).

Can anyone tell me the Dimensions ?

Your help would be Appreciated ! Fred M.

[tapetech]

That first part # MB-331022 is the tensioner belt, so you already have those dimensions.

The second part # is the belt that drive the optical wheel that drives the tape counter. Pulley for it is part of the right idler wheel. The old somewhat loose belt was Square 5.5" X .045" I installed a new belt that was 5.25" X .045" and it worked fine.

[marrscommunications]

4-30-12
Hello Tim,

Thank you for the Response on the 747 !

1 correction. The part number for the Tensioner is MB331021.

The 5.1" belt is MB331022. Do you happen to know the

dimensions for the Detector Belt ( Shut Off ) MB330938 ?

Thanks a Million Tim ! Fred M.

[toddbailey]

Belts have a inheirent built in tolerance variation, you don't need the exact size, belts can be stretched by several mm with out any harm.
Take a piece of string and thread it through the machine, then measure the pulleys etc to get an approx width. If you need a dial calper, Harbout Frieght tools has cheap one for under 8 bucks.

MCM electronics has a large collection of belts that will work, and they too are cheap, you just need to get close,

you can even find online tools to halp you determine the proper length.

Order a few in various lengths, you be able to find something close enough and save a lot of coin in the process.

case in point B&O turn table, OEM belt price was $36.00 plus another $10 to ship.

MCM's price was 4.99 and <3 bucks to ship a set.

[tapetech]

Originally Posted by marrscommunications

4-30-12
Hello Tim,

Thank you for the Response on the 747 !

1 correction. The part number for the Tensioner is MB331021.

The 5.1" belt is MB331022. Do you happen to know the

dimensions for the Detector Belt ( Shut Off ) MB330938 ?

Thanks a Million Tim ! Fred M.

You are correct: there are 2 tension arm belts (very small 2.1"?) p/n MB331021

There is only one more belt in the deck and it is referred to in the manual (747DBX) as two different part #s. I just repaired this deck yesterday, so I'm certain.

MB-331022 roller belt
MB-330938 detection belt

They are the same belt. The 5.1" belt. There is only one in the deck. This belt drives an optical wheel.

I would use the 938 number because it's the only one in the manual that actually points to a belt in the illustration. The other number does not, it's a bogus #.

[marrscommunications]

5-1-12

Thank you Tim. Much appreciated. Fred M.

[FrankC]

Originally Posted by marrscommunications

4-23-12,

Hello, I have the GX-747 Tensioner Belts In Stock, but cannot

Cross over the Other 2 Part Numbers. ( MB-331022, MB-330938 ).

Can anyone tell me the Dimensions ?

Your help would be Appreciated ! Fred M.

Hi where can I get these belts?

thanks
Frank

[captaingamez]

I just did my 747 and i got my belts from turntable needles.com i believe they are 1.9 inch and the replacements are square, contrary to what some have said in the past, the originals ARE ROUND NOT SQUARE. if you have square ones when you take them out, i have been told that someone else has been in your deck doing the same thing, the belts in the 747 are a PAIN only cause they wear out every few years. and when they do, you have to tear the top half of the front off.

word to the wise, there is a little washer in there that holds a gear on a shaft and the belt is behind it, remove it with a razor blade and whatever you do DO NOT DROP IT IN THE DECK!!!!!! make sure it is in your hand when you remove your hand from the mechanism and i recommend strongly doing this with the unit on its back as it will be easier to prevent from losing it.

if you do end up dropping anything in the akai, it will be absolutely horrible to get out, that thing is like a birds nest of wires and floors of componentry in there, and i have restored a few decks, i probably would not be very excited to touch my akai.
good luck

[captaingamez]

yup their still in stock, they are 1.9, your replacements will be square, but its not a big deal as i said. order em while you can, i had to wait a few months for them to be back in stock since they were out a while back.

http://www.turntableneedles.com/Squa...Inch_p_40.html

[marrscommunications]

5-5-12
Hello Guys,

The Round cross section replacements available today are 0.070 x 1.9".

Since the diameter is 0.070, this creates too much tension and creates problems.

I also stock the Square Style, sold in Pairs.

captaingamez : Do you have the MB-330938 detection belt in Stock ?

If so, I would like to purchase ! Thanks, Fred M.

[FrankC]

Originally Posted by captaingamez

yup their still in stock, they are 1.9, your replacements will be square, but its not a big deal as i said. order em while you can, i had to wait a few months for them to be back in stock since they were out a while back.

http://www.turntableneedles.com/Squa...Inch_p_40.html

Thanks just ordered them. Are you the guy who put the video on youtube showing how to do it? If so great job, its almost imposible to get help on here.

[marrscommunications]

Sorry, not me Frank. Thanks Much ! Fred M.

[tapetech]

Originally Posted by marrscommunications

captaingamez : Do you have the MB-330938 detection belt in Stock ?

If so, I would like to purchase ! Thanks, Fred M.

The MCM 42-160 should work fine as the detection belt. It's 5.1" X .046" ($1.40)

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[captaingamez]

no it was not me but i did find that video helpful, i just thought id throw a few tips from my experience with them my way,

can someone link me to the detection belt? i need to get one as my counter is a few seconds off rewinding a whole tape, or FF, every once in a while.

[marrscommunications]

5-6-12 Sorry Guy's, my mistake. The number / size I am looking for is the

MB-331022 ( Counter Roller Belt Reference # 5-21 ). The counter Roller is reference # 5-20.

The Detection Belt ( MB-330938 ) is reference # 7-93. ( This belt is the "sense" belt for the chopper ) Fred M.

[tapetech]

Originally Posted by marrscommunications

5-6-12 Sorry Guy's, my mistake. The number / size I am looking for is the

MB-331022 ( Counter Roller Belt Reference # 5-21 ). The counter Roller is reference # 5-20.

The Detection Belt ( MB-330938 ) is reference # 7-93. ( This belt is the "sense" belt for the chopper ) Fred M.

You were already given that information. See post #5.

The counter roller belt and the detection belt are the same belt. There is only one of those belts in the deck. The belt goes between the right idler and an optical wheel, which in turn drives the counter.

I use a 5.25" X .047" belt, but the one from MCM (5.1" X .047") that I mentioned in post 13 should also work fine. The size of this belt is not super critical.

I have re-belted dozens of the 474's and just finished one a few days ago.

[marrscommunications]

5-7-12,

Hello tapetech, I am confused ? The service manual clearly shows 2

different locations for these Belts. Are you saying it uses the same belt SIZE in

Both Locations ? Thanks again, Fred M.

P.S. You have a Super website.

[tapetech]

Originally Posted by marrscommunications

5-7-12,

Hello tapetech, I am confused ? The service manual clearly shows 2

different locations for these Belts. Are you saying it uses the same belt SIZE in

Both Locations ? Thanks again, Fred M.

P.S. You have a Super website.

I think I'm the one who was confused. Turns out that the "roller belt", referred to on page 61 of the 747DBX manual is really an idler tire. Or at least what I consider an idler tire to be. It wraps around the pulley (really an idler) at the top of page 60. I thought they were referring to the belt that loops around the roller pulley (4-43) at the bottom of page 60.

So, to finally answer your question, I don't know the size of the "roller belt p/n MB-331022". To me, it's an idler tire. Do you even supply idlers tires like that? I wasn't aware of that.

Also, my 747 PDF is mostly illegible, so I'm using the 747DBX, which uses different reference numbers. That also threw me off.

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[Pacific Stereo]

"My complications have developed complications!"

[tapetech]

This photo is similar to the item in question. They are typically referred to as idlers, so the rubber on them would be an idler tire.

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