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BM4400 Spares or Repair

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Craig
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Craig posted on Tue, Feb 13 2018 10:08 AM

How hard can it be?


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Craig
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Cut the front chamfers and marked up the cuts to allow the cover to slide ober the protruding screws of the chassis....


Craig
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bought this snappy little accessory for the dremel.....router attachment, never used one before so was a little nervous. 


Craig
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Overall, and considering no one will see it, it turned out quite well......will need to start the veneer exercise as soon as I have softened and flattened it out.


Søren Mexico
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Craig:

bought this snappy little accessory for the dremel.....router attachment, never used one before so was a little nervous. 

I like that, good for these small cuts, I have a big router that came in handy for some speaker frets

 

Collecting Vintage B&O is not a hobby, its a lifestyle.

Søren Mexico
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Craig, was just about to start on the BM 4400, got visitors, will have to wait until tomorrow

Collecting Vintage B&O is not a hobby, its a lifestyle.

Craig
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Craig replied on Mon, Mar 5 2018 7:34 AM

Soren

That's not a problem, I still have a lot of work to do elsewhere on this exercise...I'm still awaiting delivery of some components to complete the recap and replacement of the trimmers....I have however managed to complete the final cuts on the side panels for the case, the veneer is currently being flattened and softened prior to gluing in place, all takes time ;¬)

Craig

Craig
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Craig replied on Mon, Mar 5 2018 7:48 AM

Does anybody know what size the screw is that holds the rubber feet to the base of a BM4400 ?

I inadvertently tossed away the badly corroded screws when I removed the damaged/missing original feet, they are very small self tapping screws, the manual just describes them as rubber feet.

Craig

Craig
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Walnut burr strips are flattening nicely, it's taken a while to get them completely flat and they look a little pale right now.


Craig
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As I'm still awaiting delivery of parts, getting a little annoying now, I had noticed that the stereo lamp wasn't coming on when selecting the FM function,  I had purchased a replacement 3IC1 as a precaution during the last tuner episode that I undertook recently, turned out to be nothing more than the tuning lamps, however what turned up was a LM1310 with a note from Little Diode advising me that this was an equivalent for a MC1310.  


Craig
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So I replaced the suspect device with little diodes offering and it didn't work.....to make sure I was on the right track I removed the 3IC1 from my basket case 4400 and installed it in place of the LM1310 and everything worked just fine, stereo lamp comes on and off as stations are tuned in, tuning lamps don't work though...surprise surprise. The pin out of these two devices don't look massively different, though they clearly are...or could this just be a faulty LM1310 supplied by little diode?

Craig


Dillen
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Dillen replied on Wed, Mar 7 2018 10:05 AM

The only difference I can spot in those application notes, is the small capacitor from pin 3 to ground.
You could try that, but I would expect the two ICs to be direct replacements - only from two different producers.

Martin

hemenex
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according to this RCA-Datasheet of an CA1310 they should all be the same...

  hx

Craig
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Craig replied on Thu, Mar 8 2018 7:33 AM

Well this only leaves two possibility's...one I soldered the chip in badly, or two the chip I fitted was defective. In either event the solution I have opted for is to replace the LM1310 with a RCA-CA1310A, as described above, from Langrex (5 pieces for £5) and I'm going to replace the variable capacitor too for good measure.

Craig
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Early stages of sanding and finishing the side panels


Peter
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Peter replied on Fri, Mar 9 2018 11:56 AM

I love the veneer - you are rapidly becoming the repair expert in the UK!

Peter

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