Aiwa AD-F770 belts, which goes where

[HWTest]

I've bought a set of new belts but now the question is which one goes where?
The slightly bigger and thicker on the motor pulley and the capstan and the smaller and thinner between the capstans?
Or vice versa?
Does anybody know the original dimensions of the original belt A and B?

[scan80269]

I looked in the service manual for my AD-F990, but the belt dimensions are not listed. Where did you get the replacement belts from?

My guess would be the thicker belt goes between the motor pulley and primary capstan flywheel, and the thinner belt between the two flywheels. A wow & flutter meter and a test tape would be useful to determine empirically which of the two belt arrangements yields lower W&F, but this takes a bit of work.

BTW, did the original belts melt into black goo?

[HWTest]

The replacement belts are from http://www.vintage-electronics.cc/aiwakits.html
I have a service manual for the 770 (also no belt dimension there) but sadly no wow & flutter meter.
I've installed the thicker between the motor pulley and primary capstan flywheel and the thinner belt between the two flywheels but it is a guess and I would like to be sure.
The original belts looked like this:
http://web.iol.cz/pewstec/Belt1.jpg
http://web.iol.cz/pewstec/Belt2.jpg
http://web.iol.cz/pewstec/Belt3.jpg
http://web.iol.cz/pewstec/Belt4.jpg
No chance to measure anything.

[scan80269]

All three of my AD-F990 decks have melted belts that look almost exactly like yours! This is apparently very common for certain Aiwa decks! I remember spending more time cleaning the black goo from my hands than the stuck belt bits from the flywheels and motor pulley!

I still think the thicker belt should be on the motor pulley, as this helps to transfer motor torque to the main flywheel. The thinner belt is for driving the secondary capstan without causing too much wow & flutter.

Another way to get W&F measurements (at least relative readings) is to use AudioTester software with a sound card. AudioTester has recently added W&F measurement ability, and even though the readings tend to fluctuate rather excessively, it may be adequate for A/B comparison purposes.

[HWTest]

I've removed the belt bits with tweezers and cleaned the residues with toluene. It went pretty well.
It seems logical - the thicker belt on the pulley. I've measured the length of the belt path with a cotton and the path between the pulley and the flywheel is little bit longer, I think that supports the idea. I will try the Audio tester.
I envy you, three 990s :-)
I'm trying to collect the line 660, 770 and 990 and the 990 is the last one missing.

[Mike F]

I have a 770 with melted belts as well. I haven't got any replacements yet but I have successfully removed the old belts.

I'm a newbie at this - I've never replaced a belt before, so be kind(!) - is it necessary to removed the whole transport to replace the belts or can one do it without. I'd be a bit apprehensive to start taking the deck apart without some good instructions.
Can anyone help? I'd be very grateful - it was a much loved deck and it'd be great to get it going again. Thanks.

PS When I power the deck up now there's a pretty horrible noise coming from the motor. Is that just because it has no belts to work against, or is there also something wrong with the motor?

[HWTest]

I have a 770 with melted belts as well. I haven't got any replacements yet but I have successfully removed the old belts.

I'm a newbie at this - I've never replaced a belt before, so be kind(!) - is it necessary to removed the whole transport to replace the belts or can one do it without. I'd be a bit apprehensive to start taking the deck apart without some good instructions.
Can anyone help? I'd be very grateful - it was a much loved deck and it'd be great to get it going again. Thanks.

PS When I power the deck up now there's a pretty horrible noise coming from the motor. Is that just because it has no belts to work against, or is there also something wrong with the motor?

It is definitely better to remove the transport. After you remove the cover, there are only 4 screws holding the transport - 2 on top and 2 on the bottom. For changing belts you also have to remove the back plate of the transport - also 4 screws. Don't forget to remove the cassette door before removing the transport.
Here http://dataport.cz/file/175584/ASM.zip you can download the SM for the 660/770. Some disassembly instruction for the 770 are in the SM for the 660.

The motor is noisier without the belt, but horrible ... ?

[Mike F]

It is definitely better to remove the transport. After you remove the cover, there are only 4 screws holding the transport - 2 on top and 2 on the bottom. For changing belts you also have to remove the back plate of the transport - also 4 screws. Don't forget to remove the cassette door before removing the transport.
Here http://dataport.cz/file/175584/ASM.zip you can download the SM for the 660/770. Some disassembly instruction for the 770 are in the SM for the 660.

The motor is noisier without the belt, but horrible ... ?

Thank you very much! I'm going to have a go at this sometime - it would be great to get it going again.

Is it possible to get a new motor in case the old one isn't working properly?