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
Dear Members
I've an issue with a BM 8000 which is running very well with no faults but it's not storing the Volume settings and FM Stations.
I already measured a lot around IC 6 on uC Board.
With a Scope I can see the
29 Pulses on PIN 9
Store/ Read Voltage on PIN 8
Store Constant Impulse on PIN 6
Store Control on PIN 5
Input Pulses on PIN 12
But the Store Voltage (-33 V) is nailed to -10 V. Only a minimal variation can be seen about 0,5 V.
Servicemanual says -10 V (Measured at P76 PIN 5 = -10V) Technical Descr. says -12 V
As a precaution I already changed all related Transistors 7, 8, 9, 10 with new ones.
Regarding to the Servicemanual and the Technical Disription there is a difference in the circurit around TR9
In the Servicemanual the Base of TR9 is connected to PIN 13 of IC 6.
In the technical description it's Base is connected to Ground.
Here are 2 Pictures:
So what is right and what is wrong?
Or both Drawings are right?
I' ve got an early uPC Board with the soldered HF Case with the soldered mounting points.
Forgot to mention IC 6 ist already new.
Diode D5 was short, already new.
Soldered Tr 5 with both options of the Base (GND and PIN 13)
Still no success.
So any advice is welcome.
Best Regards
Chrischi
Really no one any suggestions?
Metallica would say "Sad but true"
Sorry, I haven't had a chance to investigate that problem. Since the volume store isn't working are the FM presets also not storing?I do have one BM8000 Microcomputer board here where the FM presets are not retained but I didn't try the volume preset. I should have but I got busy trying to figure out what was going on with the FM storage. The FM storage is strange because the FM station presets are still in memory but the BM8000 just isn't reading them out properly.I suspected the storage IC so have put that Microcomputer board off to the side for now. When I get back to the problem I will try swapping that memory IC first to see if that solves the issue.
-sonavor
That´s excactly my problem,
the old storage IC seems to have some FM presets stored because if I dial through the FM Band sometimes the station P1 - 9 are lit shortly. The balance is completly to the right or left side, I don´t remember in the moment. Volume is on 0.0.
With the new IC balance is middle, Volume at 0.0 and no stations are stored, all on 87.5 MHz
If I press Volume Store the display is flashing as expected also when storing FM stations.
The SM says something about exchanging the IC but I think it´s only to have some stations stored for the coustomer.
For me it´s possible to get some Skopepictures from the signals on the IC´s, there are a lot ;-))
If you have found some time to figure out what could be the cause of this malfunktion I would realy appreciate it.
Thank you very much for reply.
Best regards
Christian