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EII+ PSU Question

EII+ PSU Question

2004-01-06 by modularmoog

Is anyone here intimately familiar with the EII power supply?

My experience with switching power supplies is limited, so I have a
few questions.

I got a copy of the schematics, and it looks to me as though basically
the main transformer has a primary located at pins 9 and 10 - is this
correct?  Right now I seem to be getting pretty much no voltage to
that point.  (Needless to say there are NO outputs at any of the voltages)

Can anyone confirm for me that this is indeed the case and what kind
of voltage I should expect to see there? 

It would help a lot to track down the problem.

Thanks!

Tim

Update: (was Re: [emulatorII-list] EII+ PSU Question)

2004-01-06 by Tim Curtis

Hi Everyone -

Okay, here's an update - see if anyone has any ideas.

I've checked out the PSU and found that Q103 (the big 2N6545 Transistor) 
appears to be shorted out in every way - no resistance between any two 
pins when out of the circuit.  I don't have a replacement here - only a 
2N3055, which looks like it is rated at way too low of a voltage, if I'm 
not mistaken.

So, I then (Leaving Q103 out of the circuit) checked the voltade after 
the 4 big filter caps and found about +318V with about 60mA of AC 
ripple.  Does this sound about right at that point?

I'm trying to confirm that things look right before the transformer,

Thanks,

Tim


modularmoog wrote:

> Is anyone here intimately familiar with the EII power supply?
>
> My experience with switching power supplies is limited, so I have a
> few questions.
>
> I got a copy of the schematics, and it looks to me as though basically
> the main transformer has a primary located at pins 9 and 10 - is this
> correct?  Right now I seem to be getting pretty much no voltage to
> that point.  (Needless to say there are NO outputs at any of the voltages)
>
> Can anyone confirm for me that this is indeed the case and what kind
> of voltage I should expect to see there?
>
> It would help a lot to track down the problem.
>
> Thanks!
>
> Tim
>
>
>
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>
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Re: Update: (was Re: [emulatorII-list] EII+ PSU Question)

2004-01-07 by Tim Curtis

Okay - not looking that good...

Can anyone tell me how to test the main transformer on the PSU?  Again, 
I'm not really good with switching power supplies...

Thanks,

Tim


Tim Curtis wrote:

> Hi Everyone -
>
> Okay, here's an update - see if anyone has any ideas.
>
> I've checked out the PSU and found that Q103 (the big 2N6545 Transistor)
> appears to be shorted out in every way - no resistance between any two
> pins when out of the circuit.  I don't have a replacement here - only a
> 2N3055, which looks like it is rated at way too low of a voltage, if I'm
> not mistaken.
>
> So, I then (Leaving Q103 out of the circuit) checked the voltade after
> the 4 big filter caps and found about +318V with about 60mA of AC
> ripple.  Does this sound about right at that point?
>
> I'm trying to confirm that things look right before the transformer,
>
> Thanks,
>
> Tim
>
>
> modularmoog wrote:
>
> > Is anyone here intimately familiar with the EII power supply?
> >
> > My experience with switching power supplies is limited, so I have a
> > few questions.
> >
> > I got a copy of the schematics, and it looks to me as though basically
> > the main transformer has a primary located at pins 9 and 10 - is this
> > correct?  Right now I seem to be getting pretty much no voltage to
> > that point.  (Needless to say there are NO outputs at any of the 
> voltages)
> >
> > Can anyone confirm for me that this is indeed the case and what kind
> > of voltage I should expect to see there?
> >
> > It would help a lot to track down the problem.
> >
> > Thanks!
> >
> > Tim
> >
> >
> >
> > Yahoo! Groups Sponsor
> > ADVERTISEMENT
> > 
> <http://rd.yahoo.com/SIG=12ckk27is/M=267637.4116730.5333196.1261774/D=egroupweb/S=1705032144:HM/EXP=1073497928/A=1853618/R=0/*http://www.netflix.com/Default?mqso=60178338&partid=4116730 
> <http://rd.yahoo.com/SIG=12ckk27is/M=267637.4116730.5333196.1261774/D=egroupweb/S=1705032144:HM/EXP=1073497928/A=1853618/R=0/*http://www.netflix.com/Default?mqso=60178338&partid=4116730>> 
>
> >
> >
> >
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> > Yahoo! Groups Links
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> >       Service <http://docs.yahoo.com/info/terms/>.
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>
>
> [Non-text portions of this message have been removed]
>
>
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>
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>
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