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Proton D1200 need capacitors

M

mbates14

Well-Known Member
Does anyone know where to locate the 15,000UF 120v capacitors? what about the 22,000uf at 63v?

they are leaking, leaking so bad its rusting the chassis and blackening/corroding the circuit board. and someone brought this amp to me to restore as it is not presently working.

Anyone know where to locate them? or know what size/values that are readily available i could parallel up, that would physically fit in the chassis?

Thanks.
 
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bingo. brainstorm....

the 15000uf 100V is cheap. what if i take one of those, then add a 100uf 25V capacitor to it, considering the rails are 109V.

You are left with 14900uf, at 125V. BINGO.... problem solved :) and the 100uf at 25v can be hidden somewhere that it cant be seen.

heck even a 0.47uf at 50V wouldn't take hardly anything out of the capacitance, and it would add 50V of extra working voltage on top of the 100v.

Would it work?
 
mbates14 said:
Does anyone know where to locate the 15,000UF 120v capacitors? what about the 22,000uf at 63v?

they are leaking, leaking so bad its rusting the chassis and blackening/corroding the circuit board. and someone brought this amp to me to restore as it is not presently working.

Anyone know where to locate them? or know what size/values that are readily available i could parallel up, that would physically fit in the chassis?

Thanks.
Click to expand...

We will need you to measure both the 15 and 22,000uf caps
in both diameter and length, in millimeters.
 
mbates14 said:
bingo. brainstorm....

the 15000uf 100V is cheap. what if i take one of those, then add a 100uf 25V capacitor to it, considering the rails are 109V.

You are left with 14900uf, at 125V. BINGO.... problem solved :) and the 100uf at 25v can be hidden somewhere that it cant be seen.

heck even a 0.47uf at 50V wouldn't take hardly anything out of the capacitance, and it would add 50V of extra working voltage on top of the 100v.

Would it work?
Click to expand...

Voltages do not add like that
 
Sir.Byrd said:
Voltages do not add like that
Click to expand...

Voltages in series do.But ..capacitance don't.
voltages in parallel don't...capacitance is added.
to get 15,000 at 125v
one would need a 30,000 at 100v and a 30,000 at 25v in series.
 
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mbates14 said:
ok. there should be specs somewhere. the D1200s were all the same, no?
Click to expand...

Just grab a ruler and measure the diameter and the length.
We need to know what the physical dimensions are in order
to recommend something that will properly fit in the original
caps place. For example lets take the 22000uf caps.
They solder directly to the board and are pretty close together.
If you get a 22000uf cap that's "any" larger in diameter they both wont
fit on the board. This why we need to know what the physical
dimensions are.
 
15,000uf in series with a 4.7uf would be less than 4.7uf total capacitance. like 4.6uf
 
avionic said:
http://www.newark.com/vishay-sprague/36dy223f150dj2a/capacitor-alum-elect-22000uf-150v/dp/26M8376

For voltage yes.For capacitance no.
Click to expand...

Yea, i just realized that after i went to a calculator. phooey. Well, it was a thought. :banana: Once the smallest capacitor in the circuit charges up, current will no longer flow to charge the largest capacitor.

But i might be forced to modify the power supply to keep the rails below 100V, 9V shouldnt make THAT big of a difference because im sure the guy isnt going to pay $121 bucks a capacitor to fix it. especially when it needs ALL of them. its just not worth it, but he really wants the amp fixed, but he doesnt want to invest alot into it. So im torn down the middle on this one. Might be a lost cause. sucks though, nice looking amp. He doesnt care about authenticity, he just wants it to work.

However it does bring up another question. Why are they using such large capacitances?? according to the schematic, they use 2 of these guys in parallel per rail. so 30,000uF per rail. its crazy.
 
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I have always liked the looks of that amplifier.With the big ass analog power meters glowing green.
 
Maybe the designer had a brother in the capacitor biz~
Good luck with the repair. Sounds like a pain~
 
mbates14 said:
im sure the guy isnt going to pay $121 bucks a capacitor to fix it. especially when it needs ALL of them.
Click to expand...

There is a cheaper solution on the 22000uf caps (maybe between 20-40 bucks a piece).
The ones posted for 121 bucks are rated at 150 volts, plus they are screw terminal
which are more expensive anyway. You only need 63V and can use the snap in type.

However it does bring up another question. Why are they using such large capacitances?? according to the schematic, they use 2 of these guys in parallel per rail. so 30,000uF per rail. its crazy.
Click to expand...
Its not crazy at all, its because of what the power supply is expected
to do. The supply on this amp doesn't run at a single voltage like most
amps do. It automatically shifts upward based on signal demands, that's what DPD is.
So it needs the extra reserve so the amp can accomplish what its designed to do.
 
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IOf they are using parallel caps, you might want to consider re-doing the wiring to use two series caps instead.
If you need 30000uF/120V, try looking for 68000uF/63V and connect two in series, you get 34000/126V, the only other mod you need is a largeish resistor across each cap (47k or so) to balance the DC on them because of tolerances in capacitance and leakage current.
Another possibility would be 47000uF/63V which is a standard value, it gives you 23500uF of capacitance. It is somewhat short of the required 30000 but at these voltages and currents, the net result is loss of about 10W of peak power and few V of rail voltage. Because you are replacing leaku dried-up caps, the new ones will likely have signifficantly more capacitance than what is in there now. Also, consider that older caps were rated for +50%-25% capacitance, which brings you right in the ball-park, considering new ones are within +-10%.
 
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Mouser has these

Cornell Dubilier
15000 uF 150v and your biggest concern 3 inch diam 4.125 inch length
598-DCM153U150DC2B
Price 67.42 and IMHO this is not bad these things are getting spendy

EPCOS
22000uf 63v 2in X 4.125
871-B41560A8229M
40.68
 
ok, thanks guys for all your suggestions.

So, now its time for me to figure things out i guess and I will get those measurements and post them when i get time.

today, i ran like a chicken with its head cut off so i didnt have time.
 
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