FM-Pac and Panasonic FS-A1FX

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Por rolins

Champion (418)

Imagen del rolins

22-12-2008, 12:30

pin 48 is +12 V and pin 50 is -12 V
gnd = 41 and 43 (see here http://www.faq.msxnet.org/connector.html)
If you have a multimeter you can measure it straight from the edge connector.

Do I have to do this while the MSX is turned on? Sorry, I'm not very good in electronics. ;)

Por Erikie

Champion (324)

Imagen del Erikie

22-12-2008, 12:49

Well do you think that there is any power on the edge connector when the machine is turned off? Smile
It might be wise to ask someone who know a bit more about electronics to measure the voltages for you.
You could break your msx if you short circuit the wrong connections while measuring the voltages ...

Por rolins

Champion (418)

Imagen del rolins

31-12-2008, 23:15

I measured the voltage on Pin50 and 48. -12v is fine but I'm not getting +12v from Pin48. Is there a fix for this problem? I assume I have to replace the power supply, right?

Por rolins

Champion (418)

Imagen del rolins

01-01-2009, 14:00

While I was taking photos of the internal transformer, I discovered the two 25v blue capacitors just poop'd. LOL!
Anyway, I can replace the capacitors, soldering is no problem for me, but its the internal transformer I'm worried about. How can I check the transformer if it still working properly?

img388.imageshack.us/img388/650/fxregulators1kp9.jpg
img388.imageshack.us/img388/2479/fxregulators2zb7.jpg
img388.imageshack.us/img388/2822/fxregulators3rp0.jpg
img257.imageshack.us/img257/4040/fsa1fxtransformer1hy1.jpg
img257.imageshack.us/img257/3223/fsa1fxtransformer2et1.jpg

Por rolins

Champion (418)

Imagen del rolins

01-01-2009, 19:04

Okay, nevermind the transformer checks out. I'm getting 16.5v from the blue wire , 12v from the 2 yellow wires, and the GND is the white.

Just need to replace those capacitors. I hope that will solve everything...

Por Pentarou

Champion (394)

Imagen del Pentarou

01-01-2009, 19:26

That's glue, not electrolyte.
I'm not getting +12v from Pin48.
Check if you have +12V on the 78L12. If you have it there then follow the path from it to the expansion connector.

Por rolins

Champion (418)

Imagen del rolins

01-01-2009, 20:10

Thanks Pentarou and I was about to desolder them too. I checked 78L12 and I'm not getting +12v, so I'll just replace that part. Is there anything else I should check?

Por Pentarou

Champion (394)

Imagen del Pentarou

01-01-2009, 20:21

Check if you are getting >12V on the "I" leg of the 78L12.

Por rolins

Champion (418)

Imagen del rolins

02-01-2009, 00:16

Check if you are getting >12V on the "I" leg of the 78L12.

Yup, I checked and I'm getting 1 on the "I" leg. Is that good?

Por Pentarou

Champion (394)

Imagen del Pentarou

02-01-2009, 01:55

On that leg you should have ~17 volt (coming from the blue wire of the transformer), that's the unregulated voltage.
If the "1" you are getting stands for -value out of scale- then I suppose it's good, you are getting voltage into the 7812.

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