BM3000 type 2931 strange behaviour

After recapping a BM3000 type 2931 P5 on the touch panel would not react on touch. Instead it was activated when i touched volume up.

After that i took of the front panel and cleaned all the metal springs and corrosponding contacts with IPA. After that none of the touch buttons reacts, and the volume is going up to max level.

Any suggestions what to look after?

Thanks in advance

One extra note: at one point I acsidently shorteted the 230 V input and blew the fuse. Could that have any effect on the touch functions?

The BF... transistors in the touchpad-circuits are known to be sensitive and fail.
I suggest you check the one for the volume up pad - or perhaps just check them all.

Martin

Based on personal experience, both with Martin and making my own repair, he is likely leading you in the correct direction. 

My Beogram 3300 had something like you are experiencing. The PH button on the touch panel did not work. It would switch to the phono function by using the remote. I removed the panel and wiggled the board contact pin and just by touching the pin, it worked. 

Turned out that by replacing T9 the touch panel worked correctly.

It has been stated before on the forums. Make sure that you use parts from reputable sources. Auction sites that state that they provide the hard-to-find electronics can be "mistaken". Sites like Digi-Key can provide equivalent replacement advice and parts.

Good luck.

Hello again, and thanks for the answers.

I have looked up the part BF199, and it dosen’t seem to be availble anymore.

Any suggestions for a replacement transistor?

Thanks in advance and happy new year

I ran into the same situation looking for that impossible-to-find BF199. I contacted NTE for advice and was told:

"Yes, the NTE229 transistor will work as a replacement for the BF199 with the following note:

“Rotate the device 180 degrees to conform with the original lead configuration.”

And from Digi-Key:

"Comparing specifications, they are very close. I'd consider this a good cross based on the main specifications. If your application requires precise specs, then you may see problems (it all depends on where these are used)".

Good luck

 

I remember that you may not need to rotate the device 180 degrees. Bench check BCE in both the transistor and the board before you install. 

I have an extra NTE229 if you can't find one from a reputable source.

Thanks i’ll look into that and see what I can find

BF240 will also work.

Martin

Finally got some time and some BF240 transistors. I started with replacing the three transistors for volume up, down and mute, but the volume would still go up automatically. Then I discovered that the wire end on the flex cable soldered to this board was slightly bend and 2 of them touching each other making a short. I cut thes ends down to a lenght where they can not touch each other and now this behaviour is gone.

So now im back to nothing happens when pressing P5 (or touching the pin for that matter). But when I press volume up it will go to P5. I can still change to another channel or source afterwards. I replaced the transistor for the P5 button, and it worked for a little time until the next time I cut the power, and the this behaviour was there again.

So what do you think? Should I replace all the transistors or focus on the one for P5 button?

Thanks in advance

I just got the remote (Terminal 3000) up and running and P5 is not activated by the volume up button on that, and all functions are working from the remote.

So I guees the culprot is the touch control.

Should I just go for it and replace all the BF transistors, or does anything else come to mind?

Thanks in advance

Now its working.

I ended up replacing all the transistors, but that didnt solve the problem. Then I noticed that the connection from the transistor for P5 to the IC was intermittent.

Again it was in the flex cable between to PCB’s. This time a solder joint thats seems to newer have got enough solder.

So resoldered the joint, and P5 touch button was working again.

Thanks for the input. Even though it was not the transistors it lead me in the right direction