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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
My Beo 8000 exhibits the classic power supply cap issues, and so I'm trying to remove the circuit card to access the caps on the top side. In order to remove that board, I will need to slide it aft and the power supply transformer in the plastic box is in the way. It appears to be removed by forcing it up and out through the top, yet it won't budge. I hate to break something trying to get that card out.
Can someone please tell me how it should be done.
Thanks
It can bind a lot and quite an amount of "controlled force" can be needed.Push upwards and see if you can wiggle it a little at the same time.
Martin
Thanks for the help. It was just as you said. It looks like three electrolytics. One is red and labeled 470140. Any idea on the value of that one. It looks to large to be 470uf.
I found that cap on the drawing. It's c29. 470uf at 40V.
I intend to replace all three of these filter caps. Are there others that need to be addressed while I'm at it? It won't start as it should after it has set for a few days with out multiple attempts and fooling with speed controls.
Ideally, all electrolytic caps 1uF and up should be replaced, that's about twenty caps or more.A cap kit exists for this, I suggest you grab one andreplace the lot.There are also some areas where cracked solder joints are very common, the kit also shows this.
Martin,
Thanks for your second reply. I missed it until just now. I am new to the forum and think I may have re-posted in the wrong place.
I have an order at Mouser for I think 23 Nichicon electrolytic caps. Basically all that I could see.
Is that kit you mentioned shipping from Denmark?
I would like to read about the cracked circuit traces. I have examined the large card and find it to be a good solid card with no cracks that I can see with a printers loupe. The card in the metal case is another matter. I have not yet removed it from it's case although I have removed both covers. It is not clear to me how to remove it or if that is even necessary. That 47/10 cap will be difficult to replace.
Which board is the one with a history of cracking.?
The cracked copper traces comes when you heat the solder pads too much. The cracks will appear right where a copper trackmeets a solder pad, typically right at the circumference of the solder joint.The main board is most prone to do this but I have seen a few cases inside the processor housing too.The cracks are difficult to see, even using a microscope but you can measure them and sometimes cooling the board will cause a reaction.With good soldering/desoldering skills and tools, you will be fine.You don't have to remove the processor card from the metal housing, just take off the top and bottom covers and you will have accessto both sides.
Be carefull when choosing voltages, not all caps will work for very long if caps with a too high voltage rating is fitted.Fit a 16V component inside the processor housing, not much higher. The original is typically a 10V component and that's just a hint too tight.
Yes, the kit ships from Denmark.
And do remember ESD, those processors are very sensitive !
Okay, thanks for all the good advise. . I have a good temperature controlled soldering station and i'll make a point to keep the heat down.
It is getting difficult to buy low ESD caps in the axial format but ill revisit that to see that I have made proper choices. The radials are all low ESD. The 47u cap is a 16v so I should be good there. So far so good. I'll post again when I get them installed.
I bought quite a few 100v caps in place of 63v types. Should that be a concern? Or are you concerned mostly about the 10v caps?
Dave
Capacitors should generally not be extremely overrated on the voltage specs.There are some positions in the Beogram where it's not as important as in others in this respect but in some positions thecapacitor in question will not be excited if not driven close to its voltage rating.It will deteriorate quickly and functionality will be lost.
Low ESD - what's that ?
ESD = Electrostatic Sensitive Discharge. Some electronic components (and that includes some vital ones used in your Beogram)will be easily destroyed by static discharge, therefore a special ESD environment, special tools and handling methods are required.This is what I was talking about.
You probably ordered low-ESR caps. Why ?