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Hitachi TRK-8600E - Dodgy Deck Distraction: Naughty Noise!


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#1 MyOhMy

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Posted 04 December 2015 - 12:41 PM

Hi all,

 

I'm working on an Hitachi TRK-8600E at the moment (more of this on another thread) and I've a problem with a noisy tape deck.  I say 'a problem' but I fell There may be two separate issues here.

 

This first video is the sound the deck made upon receipt, the longer the box is left switched on, the louder and different the noise became.  No tape deck controls were in use and no tape was in the tape deck, all I did was turn the power on (function switch pre-set to 'Radio' for demonstration purposes only).

 

Camera is held close to record the sound:

 

I opened the box, gave the tape deck a clean, replaced four belts:

1 X square counter belt

1 X flat flywheel belt

2 X other square belts

 

I closed the box but a different noise is now coming from the deck.  This noise is a mechanical grinding/scraping noise sounding (to my somewhat untrained ears) as if the flywheel is scraping on the cover plate as it rotates or something very similar.  Everything seemed fine when I reassembled the deck and box.  The noise is the same when a tape is set to 'Play' or when there is no tape in the deck.  Notice, also, that when either FF or RW buttons are pressed they do not stay down.  The playback head & mechanism lifts as it should when 'Play' is pressed:

 

Can anyone throw any light on this before I open up the box again, please?  I'll check the rotary motion of the flywheel to see if there's any contact with another surface but I don't know what else to look for at this point.

 

I used belts from a 'bulk pack' and fitted belts that I felt to be the correct size.  I have to consider that one or more of the belts I fitted may not be absolutely the correct size but I've never made a mistake yet on any of the several boxes I've rebelted so far. 

 



#2 BoomboxLover48

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Posted 04 December 2015 - 11:00 PM

This has to do with motor pulley based on the frequency of the noise. Could be something sticky on that path of the pulley... Could be motor bearings .. They might need some lubrication. No other wheel go that fast to make this kind of noise.

Is the flywheel upper limit bearing still there? This one is a Teflon or hard plastic material that gives capstan approximately 1mm to and fro play.



#3 T-STER

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Posted 05 December 2015 - 03:23 AM

I'd say the noise in the second video is almost certainly the flywheel rubbing where it shouldn't, the resistance its encountering could be what is stopping fwd and rew engaging to. I would spin the flywheel by hand slowly and see at what point the grinding ocurs. Be sure to have the plate that covers the flywheel aligned correctly and the little plastic guide piece in the right spot. This has a little divot for the top pin to sit in usually. I had a panasonic do this same thing, it turned out the flywheel cover by design has a small bend in it and mine was almost straight, i loooked at pictures of someone else rebelting and found theirs had a bend to it so i replicated it and sure enough no more grinding.



#4 MyOhMy

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Posted 05 December 2015 - 06:00 AM

This has to do with motor pulley based on the frequency of the noise. Could be something sticky on that path of the pulley... Could be motor bearings .. They might need some lubrication. No other wheel go that fast to make this kind of noise.

Is the flywheel upper limit bearing still there? This one is a Teflon or hard plastic material that gives capstan approximately 1mm to and fro play.

 

Thanks, BoomboxLover48.  I'll check the parts you mention but I'm unclear about "Is the flywheel upper limit bearing still there? This one is a Teflon or hard plastic material that gives capstan approximately 1mm to and fro play.but it'll probably make sense to me once I've opened the box again and carefully examined the parts.

 

I'd say the noise in the second video is almost certainly the flywheel rubbing where it shouldn't, the resistance its encountering could be what is stopping fwd and rew engaging to. I would spin the flywheel by hand slowly and see at what point the grinding ocurs. Be sure to have the plate that covers the flywheel aligned correctly and the little plastic guide piece in the right spot. This has a little divot for the top pin to sit in usually. I had a panasonic do this same thing, it turned out the flywheel cover by design has a small bend in it and mine was almost straight, i loooked at pictures of someone else rebelting and found theirs had a bend to it so i replicated it and sure enough no more grinding.

 

Many thanks, T-STER for your help with this, I shall be taking your advice and checking these points when I re-open the box again which will be over the next day or two.



#5 jimmyjimmy19702010

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Posted 05 December 2015 - 02:44 PM

Sounds like motor bearings. A drop or two of sewing machine oil into the top bearing should shut that noise up.

#6 MyOhMy

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Posted 05 December 2015 - 04:17 PM

Sounds like motor bearings. A drop or two of sewing machine oil into the top bearing should shut that noise up.

 

Thanks, jimmyjimmy197020210,  I'll do this as well as check lubes throughout as much as the deck as I can.

 

Prior to re-belting I tried all cogs, spindles, wheels & the motor spindle and all other rotary parts for (seemingly) smooth and correct movement.  I did not do the same thorough checks once belted, only checked the deck movement(s) as a whole (without cover plate in place) and all seemed fine.

 

I'll be back onto it in the morning.



#7 BoomboxLover48

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Posted 05 December 2015 - 08:27 PM

I have both 8600 E and 8600 RM. I forgot to take pics of the deck of 8600 E but found the 8600 RM deck pic. I think they both use the same type of deck. 

 

The plastic part is mounted to the top cover. Check it has fallen off from underneath the flywheel cover. m

May be some wires are touching the flywheel. Motor bearings can lose lubrication like I mentioned before. Add a drop of singer machine oil like Jimmy mentioned. 

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#8 JVC Floyd

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Posted 05 December 2015 - 08:55 PM

that does remind me of when i got the damn tape head wires too close to the flywheel in my trc 920 same thing happened , that and the top plate that covers the fly wheels was not aligned right , but those damned decks are farking hell on earth to work on.



#9 MyOhMy

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Posted 05 December 2015 - 08:59 PM

If you mean the green mini PWB looking thing with the grey & purple wires - there isn't one present on my box.  The cover plate also differs in design over the flywheel area.  I can see other subtle differences, I'll try to replicate that photo angle for comparison and take more pics in the morning.

 

Just found two pics I took when the box was apart.

Attached File  DSCF1187sfw.jpg   131.31K   3 downloads

 

Attached File  DSCF1173sfw.jpg   148.02K   3 downloads



#10 MyOhMy

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Posted 06 December 2015 - 10:12 AM

I've now opened up the box again and taken a pic as close to the angel pic in post#7 as I can for direct comparison.

There are some differences with this deck:

Attached File  DSCF1277sfw.jpg   125.52K   3 downloads

 

With cover plate removed:

Attached File  DSCF1279sfw.jpg   144.66K   6 downloads

 

With flywheel and flywheel belt removed showing belt routes:

Attached File  DSCF1282sfw.jpg   114.45K   5 downloads

 

I also reconnected the deck once it was physically removed and found the source of the 'metallic scraping' noise.  It was, indeed, the flywheel rubbing against the cover plate.  The cause was the 'Teflon'/'poly-something' washer that fits over the spindle after re-inserting the flywheel, I had pushed the washer down the shaft and left about a 1.5mm-2mm gap that facilitated lateral movement of the flywheel/spindle thus allowing contact between the flywheel and the cover plate.

 

Note:

When the flywheel is in it's correct position with the spindle washer pushed as far down the shaft as it should be (I can confirm it's a good, tight fit), I've noticed a gap of about 1mm-2mm between the tip of the spindle (at the flywheel end) and the cover plate (the separate part of the cover plate that is angled inwards towards the flywheel and is fixed to the main cover-plate by two bent clips), is this gap supposed to be there?  There is no direct contact between the cover-plate and the spindle even though the area is greased to enable a smooth operation.  At this time, the only way to close this gap would be to move the spindle washer laterally enough to close the gap - but this is a step backward and would result in the flywheel once again scraping against the cover plate.  Also, would the spindle washer be liable to lateral movement over a period of time in use thereby resulting in the same problem?

 

Apologies for the long-winded explanation, I'm trying to be as clear as possible with every detail I can think of.

 

With the deck out of the box but still connected, tape play resulted in the same symptoms (Play/FF/RW operations) as shown in the second video (post #1), I've not yet played a tape with the box fully reassembled.

 

The idler and idler tyre condition/movement/operation appear to be alright but INE on this, I'll check this further and more closely examine the operation and idler wheel condition (under a magnifier).

 

If there are no further suggestions at this time I'll reassemble the whole box and re-test under normal working conditions.

 

Thanks, Guys.



#11 MyOhMy

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Posted 07 December 2015 - 12:59 PM

Update:

 

Just about there now.  I've followed all the excellent advice and suggestions from y'all offered so far and things are looking good.

 

My main concern at this point is the lateral movement of the flywheel/spindle.

 

I carried out 2 tests:

 

First test: I laid the box on it's back and played a tape.  This resulted in the spindle/flywheel moving in a downward direction (which would be a lateral movement towards the rear of the box if the box was in a normal, upright position), the flywheel began to once more grate against the cover plate (video 1).

 

Second test:  I reassembled the whole box, pulled the spindle/flywheel back to it's correct position & re-settling the spindle washer in it's intended place.  I then played a cassette for about 1.5 hours without any problems or issues.  There was no lateral movement of the spindle/flywheel (video 2).

 

 

 

Given that (so far) the only lateral movement in the spindle/flywheel was when the box was on it's back, I have 2 questions:

 

1) Is this to be expected?

2) Is this normal therefore I've nothing further to worry about?

 

If this is all good, I still have the issue of the spindle not being in contact with the deck cover plate by about 1.5mm-2mm.  It's almost as if the spindle is too short by this amount and would need 'something' (improvised?) to fill the gap thereby preventing lateral movement in the future.  As I said, the deck appears to work fine now otherwise.



#12 BoomboxLover48

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Posted 09 December 2015 - 10:06 PM

There is a curved washer right under the gearwheel and flywheel. This acts like a spring and like a spacer/washer. I was wondering if you missed that. This curved washer/spring/spacer basically allows less lateral movement. Plus there is another friction lock washer on the capstan. 

 

The gear under the flywheel is in a slot under it. This make contact to two gears one is black and the other is the large white one. It is a little tricky to get the main gear under the flywheel to align with the black and white gears. 

 

The washer/spring/spacer looks like a washer that has a curve the center is like 2- 3 mm high from the flat surface plane. If you press it it will go flat and when you release it will have the curved shape. 

 

So that is why you still have that 1.5mm-2mm gap. Basically it is a steel curved washer spring right under the plastic gear wheel of the flywheel.This spaces it and also protect the plastic gear axle rub against the  housing. That plastic gear under the flywheel is  rubbing on the housing with the bearing attached to it. 

 

The flat bend of the spacer washer spring was rubbing on the gear shaft under the flywheel and sharp end on to f the plastic tube holding the outer bearing. So when I pulled the flywheel out the flar bend of the washer/spacer/spring was up facing the back of the boombox.

 

It is in this order  Flywheel cover with steel leaf spring, axle (capstan outer end), Flywheel, plastic gear that is secured in a slot of the flywheel, curved washer/spring/spacer, outer bearing of the flywheel axle, and then inner bearing of the capstan.

 

I put a pic showing the shape of it. The material looks like an alloy in brass color. 

Attached Files



#13 MyOhMy

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Posted 10 December 2015 - 05:30 AM

Thanks for the detailed info, BoomboxLover48.

 

"There is a curved washer right under the gearwheel and flywheel. This acts like a spring and like a spacer/washer. I was wondering if you missed that. This curved washer/spring/spacer basically allows less lateral movement. Plus there is another friction lock washer on the capstan". 

 

Yes, all is well here, the original parts are in in place just as you have described.

 

 

 

"The gear under the flywheel is in a slot under it. This make contact to two gears one is black and the other is the large white one. It is a little tricky to get the main gear under the flywheel to align with the black and white gears". 

 

I'm sure I have this correct, the flywheel has a cog on the underside that needs to settle by rotating a little when inserting the flywheel, I'm confident I've got this right as well.

 

 

 

"The washer/spring/spacer looks like a washer that has a curve the center is like 2- 3 mm high from the flat surface plane. If you press it it will go flat and when you release it will have the curved shape." 

 

No probs here either as far as I know but, the next time I open the box, I'll make a reference to your comments to make sure I have the washer fitted the correct way round.

 

 

 

"So that is why you still have that 1.5mm-2mm gap. Basically it is a steel curved washer spring right under the plastic gear wheel of the flywheel.  This spaces it and also protect the plastic gear axle rub against the  housing. That plastic gear under the flywheel is  rubbing on the housing with the bearing attached to it." 

 

"The flat bend of the spacer washer spring was rubbing on the gear shaft under the flywheel and sharp end on to f the plastic tube holding the outer bearing. So when I pulled the flywheel out the flar bend of the washer/spacer/spring was up facing the back of the boombox."

 

"It is in this order  Flywheel cover with steel leaf spring, axle (capstan outer end), Flywheel, plastic gear that is secured in a slot of the flywheel, curved washer/spring/spacer, outer bearing of the flywheel axle, and then inner bearing of the capstan."

 

Gotcha, that's a good explanation with excellent details of the parts & this part of the mechanism.  I'll recheck this particular area & arrangement with extra diligence when I next open the box.  I know the gap I have between the cover plate and the flywheel end of the capstan (in my ignorance I've been calling this part a 'spindle' so, for every mention of 'spindle' I have made throughout the thread, please substitute for capstan!)

 

 

 

"I put a pic showing the shape of it. The material looks like an alloy in brass color." 

 

Got that, this is exactly what I have in my box.

 

Well, BoomboxLover48, your post has been an enormous help and I really mean this so I'll say it loud 'n' proud:

 

"I'm very grateful for your time & patience with this - it's all the details!"