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
Recently I received help through this forum in the case of extending the use of my BC1200(R2R) by connecting it to my (white) BM2000. I assumed that I could explore now all the features of this BM, but to my disappointment I found out that choosing the FM button there is no reaction other than the tuning lights, ON, TUNING, STEREO, and the pointer, light up when turning the flywheel.That indicates that the the problem lies somewhere else:...... where, that is now my question.The 5 FM presets are OK.
Silent Tuning enabled with a bad antenna?Power supply to tuner (board-mounted rectifier and filter capacitor) bad?
Martin
Antenna works fine with other BM's.
I will check the power supply. Rectifier and capacitor also, but, do you happen to know what component number these two have in the schematic/component list?
As usual, your help is much appreciated.
aad
I don't recall the designations, but the small round rectifier sits on the board right in front of the mains transformer and the 470uF filter capacitor right next to it.
Does this mean that the tuning lamps perform independent from this tuner power supply?
Aad
Most likely the power supply still delivers some kind of power, but the problem is ripple, from either a missing diode inthe rectifier or bad filtering. This doesn't show on the lamps.Too much ripple will cause malfunction in the tuner - and muting.
Supply of B40C600 rectifier is impossible here sofar. Any equivalent ?
A standard W06 will easily do the job.
Still looking for a 2W06 rectifier, is a 2A 600V a standard type?
how about the capacitor: is a 35V 470u a good substitute for a 40V one?
Hi,
a B40C600 is a full-wave rectifier with 40Volt (RMS) and 600 milli Amps.
So a B80C800 should do very well. You can get one from Reichelt in germany:
B80C800 (125V, 800mA)
Ralph-Marcus
concerning the capacitor: the voltage should be higher or equal to the one used before. So i would recommend a 470µF / 50V or 63V 105°C. It should fit in place of the old 470µF / 40V because newer capacitors are smaller than the old ones.
Thank you for your reactions: I will go after them tomorrow.
With the newly arrived C's and rectifiers within reach I hesite to replace the ones on the pcb: I did, a little late, some measuring and found the results as indicated in the service manual, except for the value of the cap, which shows 690uF instead of 470uF. Could this be the culprit of not being able to get the FM active? if this is no problem, where else can I search?
690uF for a 470uF capacitor is a clear sign, that it has lost its grip of things.
OK, let’s replace it.
Thanks.
Although I am aware of the fragile state of the tuning assembly I managed to break off the top right corner of this part. luckily I have a totally lame BM 2000 and was able to cut off the corresponding piece and glue it on the damaged unit.
The good news is that replacing the cap resulted in ; FM problem solved
The new cap is in place and selecting the FM push button I get good reception now, however
it took a while to get there, because first I had to repair the top right corner of the tuninig assembly which was broken off during the repair session ( fragile material after so many years in service): luckily I had a obsolete donor assembly from which I could "lend" the corresponding piece of material and glue it in place.
Anyway thanks for the help
Sorry for "double posting": I was not concentrated enough when I tried to edit my post.
Nice work!
In the photo the dial string is running on the screws body.It should run on the small black wheel.
You are a good observer or you have younger eyes than mine.
Thank you