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Hi, I'm restoring a BM 4400 and bought a cap replacement kit from Dillen.
I want to replace the bulb of the signal meter but I don't see how to get to it. I managed to access the meter and remove the plastic cover.
I think there're 2 types and this is the difficult one.
Does anyone have a clue.
EDIT by Dillen:Title corrected to read Beomaster
With photo
Yours is actually the easy one but you haven't noticed the socket. :-)Put the clear cover back on before something goes wrong.Then pull the socket out of the side of the meter (pull on the solder tabs).
Martin
So easy ! Thanks Martin.
Hi Martin, I'm replacing the capacitors of PC3 Stereo decoder and indicator circuit with the service kit you provided.
Some of the new caps have the same uF but lower voltage, 50v instead of 63v, it's C14 1uF, C16 1uF (both yellow circles on your scheme) and C29 2,2uF, C30 2,2uF (both green circles).
Just to be sure, this will not blow up the caps?
It's currently not possible to upload a picture with my phone.
Great to see that you are aware, but you can safely trust what's in the kit.
There are no voltages in the tuner anywhere near 50V so it'll be fine.
63V was a standard when the Beomaster was produced, and you practically couldn't find
low capacitance capacitors (1uF, 2,2uF etc) with a lower voltage rating.
I'm sure B&O would've used 25V or 40V components had they been available at the time.
The problem with using capacitors with a too high voltage rating is that they won't be excited and
they will die faster than if they see voltages up closer to their rating, even if only occasionally.
It's a chemical thing.
You could say that they will "die from boredom".
A good handrule is to use capacitors with ratings 10-20% above the actual working voltages.
Great, I'm not very experienced, better save than sorry :) .
For the trimpots, can I just pull them out, measure the ohm value of the old one and adjust the new one accordingly as a starter? And then adjust according service manual if necessary?
Thanks
Kristof
kbaelden28: Great, I'm not very experienced, better save than sorry :) . For the trimpots, can I just pull them out, measure the ohm value of the old one and adjust the new one accordingly as a starter? And then adjust according service manual if necessary? Thanks Kristof
You can use the apprx physical position of the old trimmers as a starting point, or you can start with the new trimmers centered.Given that the old trimmers will be - if not already bad, then at least marginal by now - you really shouldn't use theircurrent ohmic values as reference.The servicemanual will tell how to adjust.
Hi guys,
The tuner had a good reception, the signal was good but the sound quality was bad and only the left channel worked fine, the right channel was very low even when I turned the volume at max.
So I decided to first replace the caps and trimmers on PC3 (stero decoder and indicator circuit), PC2 (IF-section)and one tantal of 10uF of PC1 front-end.
Now I get just a very very weak signal if I set FM dail all the way to the left. Most of the time the meter is at it's highest (right 5).
I've first set the trimpost like the old ones then started changes all trimpost but nothing really happens, sometimes the meter goes to zero or the stereo indicator lights up but no signal whatsoever.
I have checked the tuning voltage of 2R10 but I can't go up to 25,5 V , the range is between 16,2V and 20,3V.
I didn't touch any of the front-end switches or the L1 , L2 decoder coils.
I double checked the trimpots for correct value before inserting them, but still I might be wrong there! I can't think of anything else.
What should be the first check to get a good signal ?
I noticed that the corners of the big red/black/yellow/black resistor attached outside the metal box broke off when I opened the box. The leads of the resistor seem to be intact.
Can this cause the lack of signal ?
I'm not able to upload photo's, is this a common problem?
Thanks Kristof.