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BM7000 issue after Lithium battery replacement

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MartinM
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MartinM posted on Wed, Jan 15 2014 9:42 AM

I have a Beomaster 7000 that would not keep correct time after the power was disconnected. I removed the CPU module and discovered that the Lithium battery (CR2450) was leaking. After having replaced the battery with one of the same type the Beomaster now will not respond to any commands from the remote.

The Timer Off light is on and if the Mute/Power button on the right is pressed, the display indicates 7. Successive presses changes the number from 7 to11 to 22 and back to 7 again.

Not sure if these are error codes or not. Any ideas on this fault?

 

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tournedos
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Since it lost all backup power for the NV memory, it has now random content for all programming. 7/11/22 are probably the radio station presets that are now "programmed".

Reprogram audio option 1 and it should start working with the remote again. Then go through all other setup as well.

You might need to reprogram the tuner frequency offset as well... I believe that procedure is somewhere on the forum, but I couldn't find it with a quick try. Perhaps somebody else rememvers.

--mika

MartinM
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With a scope on CPU pin 12, IR input, I can see data when pressing a key on the remote. So I'm hoping that your suggestion of setting the option is on the right track. However, I'm having trouble identifying TP1. The circuit layout of the BM7000 CPU module looks a little different to the BM6500.

I've tried with the BM on radio, pressing sound 1 store, but no response.

My circuit diagram shows Test is on pin 7 of IC3 which is a 4021. I don't see this in the CPU module that I have.

lausvi
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lausvi replied on Thu, Jan 16 2014 6:34 AM

The audio option is set with the BM in standby.

MartinM
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Thanks. That worked. However, I'm still wanting to get the BM into Testmode. I cannot identify from the drawing which pin to short as it only shows the area and not which pin to short. Here is the article that I'm looking at:

http://archivedforum.beoworld.org/forums/p/31732/256614.aspx#256614

 

 

 

RaMaBo
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RaMaBo replied on Thu, Jan 16 2014 2:53 PM

MartinM:

My circuit diagram shows Test is on pin 7 of IC3 which is a 4021. I don't see this in the CPU module that I have.

 

This is for the BeoMaster 6500. Your BeoMaster 700 has a different processor board.

You should look for the point where R48 and R58 are connected together. This is the testpoint TP1 you have to connect to ground (try it 2 times if necessary).  R48 is connected between +5 V and R58 and TP1 whereas R58 is connected  from  TP1 to Pin 32 of IC3 (the square flat chip 81C55).

Now it depends on your luck: If you have the Revision D of the processor board (or newer) , TP1 is located near the upper left edge if you hold the board with the battery on the left and facing to you, at 12 o'clock there's a single small point in the surrounding big ground plane. If you're unlucky TP1 is located just beneath the lithium battery around half of the radius at 7 o'clock.

 

Hope this helps

 

Ralph-Marcus

MartinM
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Here is a photo looking at the back of the CPU module. Lithium battery is located directly on the other side. Is TP1 in the upper left corner surrounded by the ground plane ( just above where the metal shield would cover?)

 

RaMaBo
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RaMaBo replied on Fri, Jan 17 2014 7:43 AM

Okay so you got the newer version of the processor board. The testpoint TP1 is the small dot you found correctly.

Here we go! Smile

 

Ralph-Marcus

MartinM
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I can confirm that point is indeed TP1 . BM indicates 88 when test mode is initiated. I've gone through the different test functions. Test 5 (RAM/ROM test) produces code 37. That is not in the list of codes in the service manual. Any idea on this one?

I've erased the RAM. I still get status 37 on test 5 though.

 

RaMaBo
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RaMaBo replied on Fri, Jan 17 2014 10:57 AM

The result code of 3.7 says that the complete RAM/ROM test including the NVRAM and the NV watch went fine. 

But you are still not at the end. Fiddling around with the NVRAM (or also after problems with the battery) you should initialize the processor board with the following tests in this order: First bring system into test mode then let it execute test function 16 and direct afterwards test function 7.

Now the beomaster should be controllable completely like tuning, storing, switch sources and so on.

Have fun with this nice system!

Ralph-Marcus

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