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Sony TC-8040 Info Needed

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Circular Vibes

1K Club - QQ Shooting Star
Since 2002/2003
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Location
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I have a Japanese Sony TC-8040 Quad8 deck and just had the electronics fixed by my tech. My problem is figuring out which belt to get for it. I used the string method and ordered what seemed right online and got something that fit but looked like a vacuum cleaner belt, i.e. thick and heavy. The consequence is the deck plays way too fast. I stuck an elastic band on and I get much closer to correct speed but with the expected warble. There seems to be no online reference to this model with useful info. With the elastic I get close to speed but warbly and it seems a bit weak. With the belt I bought online the motor is way too fast but the torque is amazing. Does anyone know the correct belt size? Being a Japanese deck I paid attention to buying a 60 cycle version and the motor hub has the 60 cycle attachment. I see no spped adjustment inside and the motor seems to be built to withstand a zombie apocalypse, or a long Quad8 tape but it is not a standard DC motor with a trimpot in the bottom to change the speed.
 

quadsearcher

800 Club - QQ All-Star
Joined
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Messages
862
Strange. A too-tight belt can slow the speed and damage bearings, a too-loose belt can slow the speed due to slipping, a correct belt will allow a motor to run at normal speed. I know of nothing about a belt that can make a unit run fast. Unless maybe a perpetual motion machine, ha, ha. A correct belt will transfer the drive from one shaft to another with no change.
Do you have a pdf of the service manual?
I wonder if someone stuck a 50hz motor in there. The drive shaft is clean? Rubber buildup on a turntable drive shaft will sure make it run fast.
"The frequency of electric current is 50 Hertz in Eastern Japan (including Tokyo, Yokohama, Tohoku, Hokkaido) and 60 Hertz in Western Japan (including Nagoya, Osaka, Kyoto, Hiroshima, Shikoku, Kyushu) ; however, most equipment is not affected by this frequency difference. A possible exception are timing devices such as clocks. " So if somebody moved from Kyoto to Tokyo they would want to change the motor.
 

Circular Vibes

1K Club - QQ Shooting Star
Since 2002/2003
Joined
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Location
Ottawa, Ontario, Canada
The motor is for both regions but has the 60 cycle pulley screwed on. The pulley reminds me of an old reel to reel tape recorder I had that to use the faster speed you screwed on a sleeve. This one is clearly marked 60. What I am concerned with is the belt is way thicker than any I have used on a tape player. The belt seems only slightly tight but the thickness seems to be increasing the speed. I am also using it on a step down transformer (120-100 volt) rather than plugging it straight into the 120 volt wall socket. I was hoping someone knew what the original belt size was as I have to order it online and buying multiples and hoping I get it right is a bit expensive.
 

winopener

2K Club - QQ Super Nova
Since 2002/2003
Joined
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Messages
3,611
Thickness should not affect the speed in any way, because the pulley/capstan touch the INSIDE of the belt, so it should make no difference if is very thin or more bulky.
IMHO, the belt you have make it runs at the speed it should, there has to be something in the 60/50 Hz switch that doesn't work correctly, or something else like a two-sized wheel for the capstan as some Akai units.. Check these.
 

Circular Vibes

1K Club - QQ Shooting Star
Since 2002/2003
Joined
Mar 12, 2003
Messages
1,508
Location
Ottawa, Ontario, Canada
Here is the 60 cycle pulley marked by red arrow. It can be unscrewed by hand and when I tried it without a pulley it was too slow with the new belt and waayyyy too slow with the Clarion belt.
1a.jpg

This is the 60 cycle region sticker on the botton of deck.
2.jpg

The top belt is what I bought as a replacement based on internet searches and "best guess". The bottom one is a smaller belt that I stole from my Clarion deck to try.
3.jpg

The left belt is the Clarion one, right is the new belt.There is almost a 2 millimetre difference.

5.jpg

This is the new belt in place. It tries to ride up or down making it even faster. It will not stay centred.
6.jpg

This is the Clarion belt in place. It stays centred even when I change tapes or tracks.
8.jpg

No belt in place. It looks rougher than I remember it but I had to scrape out lots of melted belt goo out. I may have to lightly sand it to smooth it out if a new belt doesn't help.
7.jpg

Front view, fully dressed!
9.jpg


I found the "new" belt to play very fast. I can only attribute that to the thickness. The belt from the Clarion is too small but the width and thickness seem to make it play much closer to speed. The sound seems acceptable enough to play my tapes safely after a long wait. I am going to try ordering a new belt that is narrower and thinner to see if it plays better. The motor has tons of torque and seems to be very similar to the one in a Techncis RS-858U I took apart to scavenge a belt from (too big!).
 

winopener

2K Club - QQ Super Nova
Since 2002/2003
Joined
Mar 2, 2002
Messages
3,611
This is the 60 cycle region sticker on the botton of deck.

This is the thing to understand: what had to be changed? Anyone can translate the japanese?
 

Circular Vibes

1K Club - QQ Shooting Star
Since 2002/2003
Joined
Mar 12, 2003
Messages
1,508
Location
Ottawa, Ontario, Canada
This is the 60 cycle region sticker on the botton of deck.

This is the thing to understand: what had to be changed? Anyone can translate the japanese?
The pulley on the motor is threaded and I had it off. That seems to be all that was needed. There were no other visible means of changing frequency.

Google Tranlate says "This set 60 Hz for the region. Actual cost will be charged separately for cycle change".
 
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