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Old 9th Mar 2021, 12:11 am   #1
TEX_360
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Default Sharp VZ3500 - door mechanical problem and advice please!

Hi all

Long time lurker, I've learnt much from the forum but now find I am somewhat stumped and need to ask for help! Please!

I have a Sharp VZ3500 vertical record deck. It's had new belts a year or so ago and has worked fine till recently. It has 2 stylus arms, one in the door, and one inside to play the front and rear sides of the record. Each stylus is suspended vertically from a thin steel cable that is pulled around pulleys by an interior motor. This tracks the movement of the record groove right to left, and when it reaches the end of the record, lifts and pulls the stylus back to the start. Mechanically the front cable is mounted in the door itself, left to right and then down each side of the door itself, where it turns c. 90 degrees around a pulley wheel mounted at each bottom corner, then inwards to the motor.

The fault is, the front stylus tracks along its groove OK to start with moving freely from right to left, but after it's tracked c. 1/3 of the record (starting position of the stylus on right) the pulley system binds and stops moving.

The stylus continues to pull and tilt laterally as its now pulled by the groove ahead of its pivot, til it's 3 or 4 cm ahead and starts to skip. The arm can be encouraged to catch back up by pulling it gently or tapping the door.

Door open and front panel off I can see the right, lower pulley wheel has worn its mounting hole much larger and the wheel is tilting and binding. I *would like to think* if I can fix this, all will be well.

Attached are snips from the service manual. it's the lower part 'bushing door shaft'; ref 221, LBSHZ0074AFZZ and ref 236 'screw, shaft, door' LX-BZ0340342AFZZ as well as the door with the opened hole.

https://www.hifiengine.com/manual_li.../vz-3500.shtml

(inc pointer on the far out view)

The pulley wheel doesnt seem to have any kind of bearing, designed just to turn in its hole in the door.

What can I do to fix this, advice welcome please!

-can I support it or replace it?

-I have a 3d printer.. I could make a solid mount and use a proper bearing? I dont know if would be strong enough but could give it a go.

Is it even possible to buy a bearing perhaps 5mm inside, 15mm outside but only 2 or 3mm wide to fit the narrow space?

Has anyone fixed something like this, what fix you please suggest?

thoughts welcome!

cheers in advance, iain

ps I can upload real pics in a day or so.
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Old 9th Mar 2021, 4:56 pm   #2
TonyDuell
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

Do you know anybody with a small (engineer's) lathe? I've not seen the part in question, but it would appear to be a relatively straightforward job to turn a replacement from whatever material you want.
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Old 9th Mar 2021, 5:12 pm   #3
G6ONEDave
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

If it's a pulley, it should either be on a shaft or if accordingley shaped have integral shafts that engage into top and bottom location holes. No good if not supported as it will tend to skew at an angle when under load from the drive cord and could cause the system to jam.

Check that all the pulleys turn freely on their shafts, likewise any gearing that's involved. It may be a sticky grease syndrome that's causing the trouble. After that check that all the drive moves manually before powering it up, you might be safest to remove the 2 stylii, to avoid damaging them, whilst doing this with the turntable out.
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Old 9th Mar 2021, 5:14 pm   #4
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

Forgot to mention. Check that none of the internal wiring is fouling the drive mechanism, the problem sometimes clears when the deck is out!

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Old 10th Mar 2021, 1:11 pm   #5
TEX_360
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

Hi,

*Thank you* for replies! I should have made it clearer it's the hole in the door that is worn. There's no bearing so the entire part is designed to turn in the hole. Not a good idea after 30+ years.

Which gets onto lubrication and make sure nothing is caught part. When i take it apart YES I will need to take extra care, and lubrication elsewhere along the loop is necessary..

What grease is appropriate?

in related news, after weeks of not finding a thing I find RS sell bearings! in a variety of different depths/widths. some seem to be only 3mm wide.

https://uk.rs-online.com/web/c/pneum...023,4294533397

Some have flanges. If I can bolt through without fouling or Superglue two parts together, one piece solid to the door, this might be the way forward.

If anyone does have experience or more ideas how to resolve, comments welcome! I'll aim to dismantle in the next week and take photographs.
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Old 11th Mar 2021, 12:11 pm   #6
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

It's a long time since I last saw one of these player units so this next suggestion might not be possible. Re the worn hole in the door, maybe open up the hole to fit a flanged bush, which would solve the worn hole issue, not sure of size required but something like a TO3 mounting bush or a larger SCR/diode type. My second idea is to rough up the hole sides and fill in with 'instant metal' or similar, then when it's fully hardened drill a new hole through it. With regard to lubrication grease, use something that does not creep too much, you don't want the grease getting onto the drive cord.
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Old 24th Mar 2021, 10:51 pm   #7
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

Hi

I've gained access to the mechanism (helpful YouTube video linked below in case it helps a future searcher ) and now I can have a proper close up look, I don't think it's the pulley that's worn. In fact, i was entirely wrong about the mounting. It's a metal peg with a free-rolling pulley pressed on. There is definitely some movement but i don't think that's enough to jam it.

So I'm going to replace the belt that drives the stylus from and rear, and clean and lithium (?) grease those pulley/wire parts that rotate. Keeping well away from the wire of course.

I can also see in the amp section a couple of largish electrolytics that have leaked, so I'll make sure I've cleared the sticking stylus issue well before looking at those. One fault at a time!

More in a few weeks.


for ref: https://www.youtube.com/watch?v=JiPkbzoIAbY
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Old 25th Mar 2021, 7:37 pm   #8
Lloyd 1985
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

Just a thought on the leaking capacitors, are you sure it’s not glue? Quite a few manufacturers used some sort of glue to hold large components like capacitors, Sony were one who loved to use a lot of it, it used to be a beige colour, but turned dark brown with age, sometimes even turning conductive! If it’s that then it’s probably best to remove it, but the caps will probably be ok.

As to grease, I personally use some automotive Lithium grease, it’s a sort of brown colour, and stays good for years, I’d avoid any Lithium grease that’s white and comes in an aerosol can, I used to use some at my old job, can’t remember if it was made by 3-in-1 or 3M, but it used to dry out really quickly, a few weeks and it wasn’t really a grease anymore, just a white smudge with bits of crap stuck in it, and totally useless at lubricating anything!

Hopefully replacing the belts will cure the sticking, all I’ve done with my 3500 is replace belts, and it’s been running fine since. Watch out if you are going to try out the tape deck, the pinch roller in mine had turned to goo, and in someone else’s too, but he didn’t notice until it was too late and ended up with a ruined tape!

Regards
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Old 25th Mar 2021, 9:59 pm   #9
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

I've had to repair a few of these - reluctantly. Change the belts and make certain the belt pulleys are clean. Check sufficient current is reaching the motor; I replaced some electrolytics around the motor servo circuit and it solved 'sticking'. I also had one with an iffy motor that I swapped with one from a scrapped cassette deck. Hope this helps.
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Old 25th Mar 2021, 10:25 pm   #10
TEX_360
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

thank you both

i think it is glue. I can see it in the video on another machine.. thats a relief.

The tape has always worked well, I've had it several years... i think thats one of the next jobs, along with working out how to get the front off. That video seems to document the basic method.

where to get belts from? Uk supplier anyone?

Lloyd - I'll get down to the Halfords tomorrow and get the grease. As luck would have it i went today and got the spray stuff! ta for the tip there... I'll swap it.

thanks also the old trout... I'll test it and will then get the meter out if its not improved


very helpful! TVM!

I shall report in a week or so
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Old 5th May 2021, 2:24 pm   #11
TEX_360
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Default Re: Sharp VZ3500 - door mechanical problem and advice please!

About time I replied. It's not much help when you see people asking for advice then not posting whether they resolved the issue or not! Hopefully it might help someone late and give appropriate thanks to those that helped!

So I didn't quite get to the bottom of the pulley problem, but I am sure I am close.

I actually saw another VZ3500 on an auction site, having changed the belts quite easily and having seen the insides of my existing machine I bought it cheap 'for spares'

To start with, no power to amp module or tape or radio. Found the voltage regulator not outputting the 31v, it had a dead Zener and a fusible link right nearby. Replaced, now works perfect.

I considered switching boards between machines but Sharp soldered several plug connections on to make it more difficult.

Turntable belt has turned to goo, that took about 20 mins to replace. Easy.

Lateral belt was missing. Cleaned and changed, I used one of the hundreds I got in a pack off eBay. Lubricated all obvious points with the tiniest amounts of oil /grease as appropriate. Works great, no sticking.

There's two speed pots on the microprocessor board, with the tiniest of movement it is now running bang on 33 and 45 rpm.

On this new machine I see the suspect stylus pulley is on much straighter so hasn't worn as much, and there's not even a trace of kink in the cable as it moves across the door, so I might yet need to reengineer that pulley or re-tension the cable. I might even be able to pop it off, swap it for one other pulley I see that's not under as much tension. I'll try that once I've surveyed it again. These machines seem easy to break.

One channel often distorts but that's the usual dirty stylus connection, swap needles front to back and it stops!

The tape deck had lost a few belts (goo) those were easily cleaned and changed.

Now the front is back on, I find the cassette no longer ejects so I need get it off again and see if the head mechanism is stuck up or needs lubrication. The deck has a weird mechanical 'arm' that sticks out backwards towards a switch on the FM board, I need trace what that's for in case something has fallen off.

So two steps forward, one back, but it's all progressing. I would just say to any VZ3500 owners, watch that video, take it slow, definitely take photos before you dismantle. It looks like they assembled it without any real thought of it being taken apart later, too many plugs are soldered on, but belts are generally OK.

I'll post again when I have fixed the tape eject and have a fix for the original stylus movement and that pulley.

Cheers all for earlier help.
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