Jump to content

How to - Fix the Bose left speaker cut out issue


HampshireRob

Recommended Posts

Before you begin have a think about whether you are competent enough in this sort of thing - you’ll be completely stripping down the radio, unsoldering some joints near to components and removing some delicate ribbon cables and springs. Added to that, you’ll end up with about 40 screws of different lengths that you’ll need to find a home for when it all goes back together.

 

And before we start, I’m assuming the Bose is already out – there are loads of resources on the web which show you how to do this.

 

In terms of tools, you’ll need a selection of screwdrivers, needle-nose pliers and a small tipped soldering iron.

 

Removing the Face Plate

====================

Use a flat headed screwdriver to prise up the plastic near the metal lugs. I found it easiest to do two either side of a corner to get going rather than two on the same side. Be careful you don’t prise the face plate away from the PCB. Once the face plate is hooked over every lug then just pull it away – it’s connected by a push fit connector which will just release as you pull.

 

1_Face_Plate_Removal.jpg

 

Accessing the Tape Deck

===================

Unscrew as shown below.

 

2_Lid_Removal.jpg

3_Lid_Removal.jpg

4_Lid_Removal.jpg

 

Now just carefully prise the bottom lid off with a flat headed screwdriver.

 

5_Lid_Removal.jpg

 

You should now be looking at the tape mechanism. Remove the 4 retaining screws as highlighted and pull the tape mechanism clear – it’s connected to the board underneath by a push fit connector.

 

7_Tape_Mech_Screws.jpg

 

You should now be looking at something like this.

 

8_Tape_Mech_Out.jpg

 

Removing the Side Panels

=====================

For the first panel remove the highlighted screws. The panel will just slide up and off.

 

9_Side_Plate_Off.jpg

 

Then remove the screws securing the second side panel. The panel will just slide up and off.

 

10_Side_Plate_Off.jpg

 

Removing the main PCB

===================

Use the pliers to twist the metal pillar so it lines up with the slot on the PCB.

 

11_Post_Wtisted.jpg

 

Pull out the white ribbon cable. That links the main PCB with the CD unit below.

 

12_Ribbon_Out.jpg

 

The main PCB can now be removed leaving the CD Unit behind (with the metal face plate still attached).

 

Removing the Front Panel

=====================

Unscrew the highlighted screws. The face will now pull off. And leave you with the CD unit.

 

13_Face_PLate_Off.jpg

 

Hopefully, you are now looking at the CD unit.

 

14_CD_Unit.jpg

 

Getting Inside the CD Unit

=====================

Remove the small black screws holding the case in place (I’ve only showed one side).

 

15_CD_Screws_Out.jpg

 

Remove the cover and you should be looking at something like this. Note that it makes no difference whether you remove the CDs or not.

 

16_Inside_CD_Unit.jpg

 

Removing the Springs

=================

Using the needle nosed pliers remove the 4 springs.

 

17_Remove_Springs.jpg

 

Removing the CD daughter-board

===========================

Unsolder the two metal posts as highlighted and use the pliers to twist them straight so they’ll fit through the slots. Then remove the two black screws.

 

18_Remove_PCB.jpg

 

Remove the ribbon by pulling the two securing clips forward.

 

19_Unplug_Cable.jpg

 

Now pull the PCB free (teasing it off the metal pillars).

 

Removing the Shock Absorbers

=========================

There are 4 in total. Remove the small screw holding each in place. Then poke them through the holes one by one towards the CD unit. Be very careful not to rip them as they may be liquid filled.

 

20_Remove_Shocks.jpg

 

Pull the CD transport free.

 

Fixing the Damaged Cable

====================

The problem lies in the ribbon cable attachment shown below. Remove the sticky plastic cover first.

 

21_Expose_Cable.jpg

 

Slide the clips forward as before.

 

22_Remove_Cable.jpg

 

Pull the cable free.

 

23_Identify_Fault.jpg

 

The line down the silver contact part of the ribbon cable is the problem. The design of the cable relies on the connector gripping the soft metal contacts. Problem is that over a period of years the vibration and temperature changes cause some of the contacts to become marginal…and for some reason the track which carries the left channel suffers the most.

 

It’s a bit of a hack but what I did was to re-insert the ribbon, but not as far in, so that the connector was gripping a nice thick piece of wire.

 

It might come back after a few years…who knows? An alternative is to buy another ribbon, perhaps with a less-soft compound that will not deform as much.

 

Re-Assembly

==========

Now the fun begins…got any pieces left?

 

Tip

===

Print off my guide and every time you remove a screw, sellotape it to the print out exactly where I removed it.

 

Good luck guys,

Rob.

 

:band:

Link to comment
Share on other sites

  • 2 months later...
  • 2 weeks later...

stew may have a point it seems like quite a few people just dispose of their head units with this fault so why not use the forum start asking for peoples old ones and refurb them im sure there would be a market for them ebay or even on here perhaps

Link to comment
Share on other sites

  • 3 weeks later...

Cheers for the feedback guys - much appreciated.

 

Have thought about doing it as a little sideline. However...

 

1. My wife would kill me (i'm in the middle of gutting the house and modernising). Every hour fixing radios would be an hour away from rewiring/plumming and family time, etc.

 

2. There'll always be one person who sends a dead unit, claiming "it worked fine before apart from the left channel problem", or "it never skipped before, you owe me £500". Sorry, it's the blame culture we've got now that makes this sort of thing quite unappealing.

 

I work pretty hard anyway and my spare-time philosophy has shifted towards 'quality' time (driving/kids/house/wife - you guess the order?). I'd rather everyone just benefitted from my experience (hence the original post).

 

To those who decide to do-it-yourself...good on yer! It's actually quite fun. If you've got any questions or get stuck, just ask, I'll be more than happy to help.

 

Rob.

 

P.S. Off-topic but personally I don't think the Clarrion / Bose kit is much cop (lots of fairly low-rent electronics in there - all done to the lowest bidder as with most things these days). I can understand those of you who rip the stuff out at the first opportunity.

Link to comment
Share on other sites

I actually want mine to stop working so i can bin it and start again with a better head unit ect...

 

i am also waiting to replace my exhaust but the bloody thing won't fall off :lol::lol: just time ehh !!

Link to comment
Share on other sites

Don't know about the specific cause of the Bose skipping issue. However, it'll probably be down to:

 

1. Over a longer period of time all lasers will loose strength to the point that the laser pick-up gets a marginal reflected signal and can’t differentiate signal to noise - and the unit skips. The more you play it, the more it degrades. Some degrade very quickly (cheap materials/design compromise). Some Sony kit was notorious for this ~10 years ago leading to a class lawsuit in the US.

 

2. Over a period of time the bearings on the electrical spindle motor wear and the precision of the spinning plane reduces - and the unit skips. Same as above but needing a new motor.

 

3. Same for the motor guiding the position/angle of the laser itself.

 

4. As everything is built to the lowest-bidder the lenses on mass produced CD kit are often plastic. Over a period of time the heat generated by the amps can 'dry out' the lens and change the laser focussing properties (like its gone long/short sighted and/or developed a cataract). And you've guessed it - it causes it to skip (often related to issue 1 above).

 

5. The CD transport suspension is failing. This is very unlikely. Looks like a pretty good design inside, and not prone to wear.

 

6. Moisture. Hot to cold causes condensation on the disk and lens. Does it behave worse in hot/cold/humid conditions?

 

7. Dirty lens – try giving it a clean.

 

Having coaxed an old Sony DVD player back to life I’ve read-up on all the above over the years. Replacing a laser pickup with a new one is costly – they are often obsolete and the few that are left go for a premium (£100+ not uncommon).

 

In the end, I bought a base model player from the same family and transferred the whole CD/DVD transport mechanism. Cost me £10 for a broken donor.

 

If I was a betting man I’d say that the “Bose†(Clarion) and non-Bose (probably Clarion too) share the same transport. Probably your best bet is to get a cheap non-Bose unit and swap the transport.

 

Hope this helps.

Link to comment
Share on other sites

Very informative rob! The head unit's worse when its colder! Iv also found that genuiene cd's can be worse for it than copies

Iv got another head unit which I bought off a guy on here which he said was working at the time so dont know whether to go to the expense off having that put in and reworked with the ecu on mine! (Is that a big job rob?)Or whether or not to try and have mine repaired!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...