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General Category => Amstrad CPC hardware => Topic started by: GUNHED on 16:21, 30 August 17

Title: Problem with super CPC
Post by: GUNHED on 16:21, 30 August 17

Hello. A while ago I bought a CPC in a PC case and it didn't work. Now I got one component out and it works. But I don't know what this component does or if I need it. The component is between the power supply cable (230 V) and the big transformer. It contains two fuses, which always blast if I connect power. The fuses are 1 A at 250 V (before they were 0.8 A, but it seems not to matter).


The component looks like this, what is it?


[attachimg=1]


[attachimg=2]
Title: Re: Problem with super CPC
Post by: tjohnson on 16:34, 30 August 17
Quote from: GUNHED on 16:21, 30 August 17
Hello. A while ago I bought a CPC in a PC case and it didn't work. Now I got one component out and it works. But I don't know what this component does or if I need it. The component is between the power supply cable (230 V) and the big transformer. It contains two fuses, which always blast if I connect power. The fuses are 1 A at 250 V (before they were 0.8 A, but it seems not to matter).


The component looks like this, what is it?


[attachimg=1]


[attachimg=2]
Hmm interesting is that a bridge rectifier to convert ac to dc.  I'm sure Bryce week be along shortly to help out :)

Sent from my E5823 using Tapatalk

Title: Re: Problem with super CPC
Post by: GUNHED on 17:03, 30 August 17
Quote from: tjohnson on 16:34, 30 August 17
Hmm interesting is that a bridge rectifier to convert ac to dc.  I'm sure Bryce week be along shortly to help out :)

Sent from my E5823 using Tapatalk


But seems to output AC too, because without the device the CPC works.
Title: Re: Problem with super CPC
Post by: luismcv on 18:12, 30 August 17
It's a power line EMI/RF filter.
Title: Re: Problem with super CPC
Post by: GUNHED on 07:48, 31 August 17
Thanks, so it does erase spikes from the power supply, right?

Then I can leave it out, because it seems to have a short.

Thank you very much!!!
Title: Re: Problem with super CPC
Post by: Bryce on 11:19, 31 August 17
It a common mode choke (Gleichtaktdrosseln). It's function is to make spikes on the 240V supply cancel each other out. They tend to fail to a short quite often (especially in Amiga PSUs). You can safely leave it out. If you still want the fuses to be part of your system, then remove the choke and connect the 240V blue/brown wires to the two output pins where the choke was soldered.

Bryce.
Title: Re: Problem with super CPC
Post by: luismcv on 20:25, 04 September 17
Quote from: Bryce on 11:19, 31 August 17
They tend to fail to a short quite often (especially in Amiga PSUs).

Or worse... :D The one in my Commodore CBM did this:

[attach=2]
Title: Re: Problem with super CPC
Post by: Bryce on 08:11, 05 September 17
Quote from: luismcv on 20:25, 04 September 17
Or worse... :D The one in my Commodore CBM did this:

[attach=2]

That is (was) a capacitor, not a common mode choke... and I bet the house stank after that happened! :D

Bryce.
Title: Re: Problem with super CPC
Post by: luismcv on 11:38, 05 September 17
Quote from: Bryce on 08:11, 05 September 17
That is (was) a capacitor, not a common mode choke... and I bet the house stank after that happened! :D

Bryce.

No, no. What explode was probably one of the capacitors on it, but it wasn't just a capacitor, it was a line filter:

[attach=2]

And yes, it smoked and smelled funny.
Title: Re: Problem with super CPC
Post by: Bryce on 11:41, 05 September 17
Yes, it's a line filter capacitor, not a line filter choke (inductor).

Bryce.
Title: Re: Problem with super CPC
Post by: luismcv on 15:21, 05 September 17
What does μH stand for then if not inductors? It even says "Drossel" (choke, afaik) there.
Title: Re: Problem with super CPC
Post by: Bryce on 15:29, 05 September 17
Yes, there were 2 inductors in there too, but the main component that exploded was the capacitor. According to the casing it had 3 capacitors 0.1µf and 2x 2500pf. One of these is what exploded, not the inductor.
The part that Gunhed referred to doesn't contain any capacitors, just two inductors that are in series with the powerlines. These don't explode, they just short out. Yours is the exploding type. :D

Bryce.
Title: Re: Problem with super CPC
Post by: luismcv on 16:21, 05 September 17
Quote from: Bryce on 15:29, 05 September 17
The part that Gunhed referred to doesn't contain any capacitors, just two inductors that are in series with the powerlines.

In his picture I see a capacitor in the schematics and in the specs 0.12µF.
Title: Re: Problem with super CPC
Post by: Bryce on 08:04, 06 September 17
Oh, you're right. I hadn't noticed that, I thought it was a pure choke. I probably only looked at the symbol.

Bryce.
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