BeoGram

Re: Beogram 4000 care

tournedos — Sun, 12 Apr 2009 12:44:54 GMT

Just to add a little hint - for the two big 4000uF/50V caps, it is a bit difficult to find replacements that will physically fit without modifying the bracket or leaving it out altogether. For my BG6000, I managed to find 4700uF/63V axial electrolytics with physical size 25 x 50 mm, and they fit perfectly (the old ones are also 25mm in diameter) - I simply had to rearrange the wires a little since one of the contacts was now at the other end.

I left the 150 uF bipolar alone because there simply was nothing wrong with it.

Re: Beogram 4000 care

Dillen — Sun, 12 Apr 2009 10:58:02 GMT

Note that one of the caps is a bipolar type, used for the AC motor.

You may have to readjust the motor phase to compensate for the capacitor change. It's in the service manual.
I agree, no need for low-ESR, high-temp, ultra-hygro-aero-antimagnetic-acidfree space-copper spec caps.

Some people like to mount low-ESR caps everywhere as a rule, simply because they think they are
better caps, but actually the use of too-low-ESR caps will in some cases add to component- and circuit
stress, especially where rush-in currents and impedance is concerned. Different cap types are meant for
different purposes and their respective circuits were designed to match.
What you need here is simple capacitance. Use 2200uF instead of 2000uF etc, that'll be fine.

Regarding voltage ratings, it's correct that a cap with a higher voltage rating will substitute a lower one but
it shouldn't be unnecessary high either. Substituting a 16V electrolytic capacitor with a 63V is generally
not recommended unless as a temporary solution.
An electrolytic cap will need to charge to near full rating, at least occasionally, or it will degrade faster.
It's chemistry, comparable to rechargeable batteries that only ever get charged to 10-20% of full load, they won't last long.
Having said that, some circuits are designed a little optimistic, the dolby chip supply capacitors in the
Beocord 3300 springs to mind - and upgrading from f.e. 16V to 25V will be fine but no higher, mounting 63V
caps in these positions would be wrong, suggesting ignorance or even lack of electronic knowledge.

Martin

Re: Beogram 4000 care

ProGram — Sun, 12 Apr 2009 09:53:32 GMT

Oh that's interesting. There is really no need to get the exact values, because they are in the power circuit and have nothing to do with sound directly, but a little higher is even better, same matter with the voltage. Yes you can switch to 100 V, for example most of the 1 µ have now 63 V instead of 16 or 25 and they are even smaller. The low ESR or 105° C caps are special for switching power supplys.

But if you want to have it original, get the exact values

Re: Beogram 4000 care

raphdjp — Sun, 12 Apr 2009 06:12:06 GMT

and what about the "low impedance"and "low leakage" characteristic?

Re: Beogram 4000 care

raphdjp — Sun, 12 Apr 2009 05:24:49 GMT

thank your for all your advices. My skill in electronique and capacitor is very bad so i have some questions:

-somes manufacturers seems to still manufacture electrolytic capacitor with the sames values (2000,3000...). Should i try to keep the new capacitors as close as possible to the original?

-For voltage (capacity, price and footprint equal), is it true to say that the highest value will be the best? (ie can i switch 15v to 100v?)

Re: Beogram 4000 care

ProGram — Sat, 11 Apr 2009 11:16:02 GMT

Hi,

yes, these are the ones, but the values are no longer avaliable, so get 2200 µ instead of 2000 µ and 3300 µ instead of 3000 µ and 4700 µ instead of 4000 µ in each case the same or higher voltage. 0C7 is a capacitor for frequency-networks (speaker). You can get those in a electronic store where you can choose that fits the best mechanically. For 0C5 is no need to change.

Re: Beogram 4000 care

raphdjp — Sat, 11 Apr 2009 06:45:47 GMT

ok, i will take my iron solder

i need to change all the 7 cap listed bellow?

Where can i find this kind of capacitor?

Re: Beogram 4000 care

rayfenwick — Sat, 11 Apr 2009 01:16:52 GMT

Definitely capacitor replacement time. Electrolytics age badly - those are looking rather sad indeed, and are likely to be way off-spec electrically.

Change them now and relax for the next 20 years.

Leave them in and the deck is likely to start doing all kinds of odd things...plus there's the risk of damage to other components - definitely best avoided.

Re: Beogram 4000 care

ProGram — Sat, 11 Apr 2009 00:37:53 GMT

Hi,

this looks definitely not normal! Are there holes or blisters in the black rubber of the capacitors (the grey tubes)? Nevertheless, i would change them after all these years. Nowadays caps are smaller in size, so maybe you look for those with a higher voltage (and -nearly- same farad) and/or pack them in foam.

Re: Beogram 4000 care

raphdjp — Fri, 10 Apr 2009 13:37:07 GMT

or Maybe it's just the normal aspect of this weld?

Beogram 4000 capacitor replacement

raphdjp — Fri, 10 Apr 2009 13:29:57 GMT

Hi, i give a second life to my father's Beogram 4000 after a long sleep period. It's working wonderfully with my Beosound 9000, after some adjustements...

Having a look at this component (capacitor?) it's seem that i'll have some trouble later. Do you think it's time to change them? Do you see some other component that i might preventively change after 35 year?

Thank you for your advice ;-)