Yamaha KX-330 Running Slow

[bisonrav]

Recently bought a Yamaha KX-330 for 99p on Ebay, mostly for digitising old cassettes. After running a few timing checks I find it's running about 3% slow on playback. The speed is constantly slow, i.e. it's not wowing and fluttering in any way.

Having searched around I've determined it's going to be one or more of lubrication, belt or motor speed control. So I whipped it open last night, and found no obvious places to lubricate, no sign of where the belt is, and no motor speed control pot.

Apart from that I'm well on top of this...

So the questions are:

1) where exactly (in simple terms) do I lubricate and what do I use to lubricate with?

2) where is the belt, and how do I get at it?

3) and does anyone know where the speed adjust is. Looking at the drive mechanism from the back, there are two motors, one left and one right. The one on the right has a small hole with what looks like a rubber seal, but the seal is recessed right into the motor, i.e. it doesn't appear to be a removable bung. The pots on the main board are all clearly identified, but there's nothing at all on the cassette mechanism.

I can take photos if it will help, wasn't able to locate a service manual anywhere.

 

[Bob91343]

The hole in the motor is probably access to a speed adjustment.

Having said that, I would not recommend messing with it unless you know what you are doing. A belt wouldn't cause slow operation unless it was excessively tight, which isn't likely. Lubrication wouldn't usually be the cause because the speed is steady, and in general the only place you dare put lubrication is the capstan bearing.

If there is a belt, it's usually wrapped around the flywheel.

 

[Jon_Logan]

Yep, the motor speed pot is on the motor, accessed through the back of the motor (hole)/

Places to lube: pinch roller bearing, capstan sleeve and thrust bearing. and the motor's sleeve and thrust bearing. Outside of that, how are the take-up and supply reels driven? If they are driven off of the Capstan motor, make sure the take-up clutch is nice and smooth, A take up torque of ~40gr/cm (smooth!) is what you should measure with a torque tape. The supply back tension should be about 3~8gr/cm (smooth).

The speed should be measured/adjusted with a speed tape and a counter (3000Hz/3150Hz).

 

[dr*audio]

Usually the speed needs to be adjusted and lubrication is not necessary and won't fix the speed problem. You should use a speed adjustment cassette tape, with 3.15KHz tone on it, and a frequency counter on the output of the deck, to adjust it properly. You adjust the speed so the frequency is correct. Sony still makes a cassette frequency / wow and flutter tape. 8-191-267-24 Description: WS-48B
Available here: http://www.partstore.com/Part/Sony/Sony/819126724/New.aspx

 

[bisonrav]

Thanks, and anyone with a photo of Hackett at the tail end of the Gabriel era is certainly to be trusted.

One last question about the speed adjustment hole, presumably I just poke through that with a jeweller's screwdriver and find a screw? What sort of travel do these things usually have?

 

[Jon_Logan]

Thanks, and anyone with a photo of Hackett at the tail end of the Gabriel era is certainly to be trusted.

One last question about the speed adjustment hole, presumably I just poke through that with a jeweller's screwdriver and find a screw? What sort of travel do these things usually have?

The rotation is usually 270 degrees. Use an insulated handle. If you touch the metal, it will likely influence the speed. Try to put some shrink tubing on the slotted driver's shaft. You don't want to short the wiper to the motor housing.

 

[dr*audio]

The rotation is usually 270 degrees. Use an insulated handle. If you touch the metal, it will likely influence the speed. Try to put some shrink tubing on the slotted driver's shaft. You don't want to short the wiper to the motor housing.

What Jon said!:thmbsp: