I'm searching for schematics for a Sharp wq-t484

[rivetmaster]

Hey boomboxery people. I've done some rattling around on the web for a service manual for the Sharp wq-t484. I've come up dry. I don't normally ask for help, but here we are.

There is a spring loose on the back plate of the cassette mech. I can't work out where it sits. It'sthe black return spring in the photo. Is it broken?
Hope you can help.

 

[caution]

Service manual can be found here.
Scroll down to PDF page 30 (SM page 40) and you'll see that spring along the left side, item 72.

 

[rivetmaster]

Service manual can be found here.
Scroll down to PDF page 30 (SM page 40) and you'll see that spring along the left side, item 72.

That's awesome. Thank you.

 

[Radio raheem]

this is a great box....good luck with the repair...it takes 10 c batteries amazing for a small box like that

 

[rivetmaster]

this is a great box....good luck with the repair...it takes 10 c batteries amazing for a small box like that

Cheers Radio Raheem. There's a few problems, but I'll see how far i can get before I cry for help.

 

[BoomboxLover48]

It is spring 72 but hard to figure out where it goes. May be where the green arrow points.... Hard to figure out unless you see it. Look for a section that is loose on an axle with a loop to catch, in the proximity of the spring. The green arrow pointed portion don't look like a section that is spring assisted.

 

[rivetmaster]

It is spring 72 but hard to figure out where it goes. May be where the green arrow points.... Hard to figure out unless you see it. Look for a section that is loose on an axle with a loop to catch, in the proximity of the spring. The green arrow pointed portion don't look like a section that is spring assisted.

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Thanks for that. I spent a good few hours taking the mechanism to bits. Having had a good examination I realised the orientation of the spring on the schematic is in the relaxed state. It actually points to the right and butts up against the cam profiles of gear 22.

 

[rivetmaster]

It's a complicated mechanism. I've fitted new belts and cleaned every part I can. So now ffwd and rew work on both 'decks'. But it wont play. The solenoid clicks and the motor spins but none of the gears move.

 

[caution]

The solenoid usually engages something so that the mode gear can turn and its cams lift the head assembly. Can you tell if the solenoid is engaging any mechanisms when it clicks on?

 

[rivetmaster]

The solenoid usually engages something so that the mode gear can turn and its cams lift the head assembly. Can you tell if the solenoid is engaging any mechanisms when it clicks on?

The motor runs for a short while after the solenoid clicks, but it's not moving the heads.

 

[rivetmaster]

I have also tried lifting the heads manually and they move fairly easily. It might be easier with a video.

 

[rivetmaster]

 

[BoomboxLover48]

Like caution pointed out the solenoid when it activates, has to engage some part on the gear and lift the head assembly. Manually raise the head and see what all sections are involved in that movement. See what is hanging around the mode gear and learn how it facilitate the movement of the play head mechanism. Do you see a missing arm/follower that engage with the gear and the head assembly movement? It has to be a cam and follower mechanism. We have to find the follower here, or both and how it is connected to the solenoid. I understand it is easy to say all this and in reality, it is very hard to locate all this.

I have worked a lot on cassette decks, and some are so complicated. Fixed many and was unsuccessful in some cases. I have a like new AKAI GXC735D that I am working on also has the same problem with the play function activated by soft touch buttons. I was unable to find the cam and follower! I lost lots of hair over the years and decided not to fool around with after trying more than 25 times working on it.

 

[rivetmaster]

So after 6 hours I've tried a few different thing. Having stripped the mechanism down to the gears and re-built it 4 times I know a bit more about it. It's still doing the same thing. The solenoid moves the followers across the cam (there are two followers), but the cam is not turning when the motor runs. Therefore the head lifting part of the mechanism doesn't engage. If i reach in and spin the cam a tiny amount then press play the heads lift into place and drop again.

 

[rivetmaster]

Before cleaning.

 

[BoomboxLover48]

It looks like you are getting very close to identify the problem. Good luck!

 

[Spax]

I have a couple of Sharp's with that cassette mechanism in my to-do pile. I'm not looking forward to them. Good luck with the fix and please document it, I may be reffering to it in the future!