Help Recognizing early Apple II PSU

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Help Recognizing early Apple II PSU

Hi,

I have this Power supply but don't know if is original or a Clone. Outside stands it's 115V/ 60Hz, but inside has a RFI filter 230V/ 50-60Hz

It's an A2M001 and 820-0003-01 is written on the PCB.

Thanks.

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Image icon IMG_9253.JPG1.73 MB
Image icon IMG_9254.JPG1.99 MB
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Image icon IMG_9256.JPG1.04 MB
Image icon IMG_9258.JPG1.12 MB
Image icon IMG_9259.JPG2.52 MB
Image icon IMG_9260.JPG1.43 MB
Image icon IMG_9252.JPG2.25 MB
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That is the power supply

That is the power supply Apple used before the Astec supplies

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David_M wrote:That is the

David_M wrote:
That is the power supply Apple used before the Astec supplies

Yesterday it stopped working, no voltage through that rfi EF1 filter...

Thanks.

 

 

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Sadly. a lot of older Apple

Sadly. a lot of older Apple power supplies need rebuilt these days.  The caps in particular go bad over time.  I'm not sure I'd rebuild that one due to its collectible nature.  I might be inclined to store it as-is and buy a new power supply to use instead.  You can go two ways on that, buy a used Apple power supply of newer vintage and maybe rebuild it if necessary or buy one of Henry Corbis's brand new ones from ReActiveMicro

 

https://www.reactivemicro.com/product/ultimate-universal-power-supply/

 

Either way I'd probably keep the original one as-is.

 

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Well, I have some spare ones,

Well, I have some spare ones, that are more modern... but the point is having the system as much original as it used to be and time to time start it up like an old car.

By the way, any page or document for fixing that kind of  Power supply ?

I only know this :

http://www.appleii-box.de/D04_allabotpowersupplies.htm but it's only related to Astec

 

 

 

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Well, where I'd start is

Well, where I'd start is checking to see whether the power supply functions if you bypass the RFI filter?  If so, then you somehow have to find a replacement for that part.  It looks like something that was probably pretty commonly used back in those days, so you may be able to find one from another power supply, possibly from some other kind of equipment.

 

 

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Also I'm assuming you've

Also I'm assuming you've tried jumpering across the power switch.  Those rocker switches often fail, so that would be the first thing to try even before the RFI filter.

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What I did is try to open

Have you tried to replace that filter?

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What I did is try to open

What I did is try to open that filter, now I know I’ve shouldn’t done that...So need to get a new one.(already ordered). I tried to overpass that filter but was through the switch but didn’t work so may be there could be the problem. I’ll Try it today through a direct connection to the coil.

thanks

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I checked the voltage throug

I checked the voltage throug the filter and is 130V also the switch so I connected it and no 12/5V on the other side... 

 

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See topic Repairing Apple II power supply

The schematic is in the Reference manual. This supply is difficult to repair since I  could not find the Bill of Materials or  component layout drawing.

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Now it’s alive but...

I measured voltages between the 2 ohm cemented wire wound m resistor and was 0V. I changed it for a 2.2 Ohm(couldn’t find exact value) Now The psu is ticking anytime Is switched on. Voltages are around  5 V but decreasing .

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Was there a load on the power

Was there a load on the power supply when you measured the 5V? To improve effeciency, some power supplies will not regulate unless there is a small load on it.

BTW, if you still have the power supply open, can you tell me what the value of the top left horizontally mounted resistor is? (It is near 2 ohm resistor, R1). It is burnt on my  A2m001 supply that I am trying to repair. 

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I replaced all capacitors,

I replaced all capacitors, the problem still exists. Ticking and variable voltage...

 

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drakepirate wrote:I replaced

drakepirate wrote:

I replaced all capacitors, the problem still exists. Ticking and variable voltage...

 

 

Have you metered all the resistors to make sure none of them show open or dead short?

 

If they are all good, then I might consider replacing all the diodes next.

 

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That was the problem, when

Cordy wrote:

Was there a load on the power supply when you measured the 5V? To improve effeciency, some power supplies will not regulate unless there is a small load on it.

BTW, if you still have the power supply open, can you tell me what the value of the top left horizontally mounted resistor is? (It is near 2 ohm resistor, R1). It is burnt on my  A2m001 supply that I am trying to repair. 

That was the problem, without load, variable voltages and ticking...when you connect it to the motherboard, it finishes ticking and everything is fine...

I replaced all capacitors and the RF filter, for nothing... 

Thanks for your help!

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Replacing the caps was

Replacing the caps was probably not for nothing.  More like preventative maintenance as most of them it is more of a when they will go bad and not if.

 

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