ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
An other/another request for help this time.
I got a Beomaster 2400 this week, good sound, but a few incandescent lamps were broken and by now replaced. Tuning is OK, volume control up and down soundwise also OK, but even after mounting new bulps, they are not shining. Do I have to look for a culprit in the schematic section as depicted in this picture?.
As usual I am looking forward to any suggestion..
Aad
Is the 15V supply present across the two lamps?
Martin
As soon as I am home I will check the 15V
just to picture a clear situation: I “borrowed” the lamps from a donor BM1900.
Meanwhile an electronically experienced friend of mine was trying to find the cause of a problem in one of my BM2400 twinbrother/sisters, a BM 1900.The latter , subject to a minor cosmetical operation all of a sudden, while I was lifting it grabbing by a heatsink, that appeared to be a little loose, changed playing music for a fat humming. I immediately switched it off and did not touch it until handling over it to my friend later. Upon switching it on he informed me that there was a very loud familiar sound: music that was, but through one channel, which was not to be silenced , nor did the volume control react on trying to balance the output properly. What could now be the problem? ( I will still remain a B& O addict, nevertheless)
I hope that this post is not rejected as a non direct relevant BM 2400 issue.
I checked 2 spots: the picture shows where i found two voltages;
whereas the diagram requires 7.9 V, I find in my case 2.25 V and one lamp shining, eaqual intensity at all volume levels.
Where goes it wromg?
Where goes it wrong?
Again: Is the 15V supply present across the two lamps?
I need some explanation : do the pictures help to presize what you ask?
"Real world""
If you are absolutely sure that the lamps are correct specs (don't trust the servicemanuals, most of them have a typo),I suggest you replace TR12, TR13 and D13.
I am sure those are the correct lamps: they come from a srapped obsolete BM1900 and had virgin solderings.
There must be in my scrap parts somewhere those TR's and the D (BC549C, BC558B and D4148).I will test them later, I'll be away for a couple of days.
Thanks so far,
The lamps have proven to be the correct ones: the 2 TR’s appeared to refuse their tasks: both were faulty:
After having replaced them by good ones the BM2400 is doing well, I thought, because in the process of getting the volume indicator working properly I did not notice that there was only one channel producing sound, caused by the balance slider. It appeared that one of the tiny basterds inside had come off his plastic fitting which one was not damaged: replacing this small part brought back 2-channel sound.
So all is well that ends well, thanks to your help, although there are more patients waiting.
(Where corona virus should be feared I still do not take any drugs against the B&O virus)