My Crazy SP-12!!!

Ayman59 · My Crazy SP-12!!!

Hi guys,

I'm happy to see that a consistent forum exist for SP users!!!

Here are the synptom: Confused

When I power up the SP boots leds on and off normally and after a few seconds leds are going crazy and the SP looks like powering off slowly!!!

After some researches I decided to bring +5VDC to VR4 (the wire mounted voltage regulator) with a PC style power supply that works great apparently but having no sounds at all.

Then I decided to replace VR4 with another LM350T (is that the correct model?) and this bring me back to start... booting working a few seconds and power decreasing until... nothing... Sad

If there's any elctronic skills in here!!! Please save my SP-12!!!!!!!!!!!!!!!

PS: Sorry for my english! I do the best I can Wink

essence

I'm not sure I understood what exactly you did with a PC power supply...did it fix the problem of all LEDs going crazy ?

I'd check all solderings and the capacitors -> "..looks like powering off slowly..".

goldenmean · .

yeah, i dont know what exactly you were swapping out there but is sounds like you are all over the place. the first place id check is the power supply...check the voltage on that. it sounds like maybe the supply is initially holding its charge on powerup but unable to maintain it. could also be a faulty capacitor.

Ayman59

Thanks guys for your lights Very Happy

VR4 the voltage regulator is regulating the +5V supplied to the analog stage of the SP if I'm right, so I supplied with the ATX power supply these +5V instead of the VR... that's how it has been working (but no sound).

I did check solderings, I also tried to push slowly on each chip, but did not check capacitors!? How should I do it ??

Anything about the checksum verification??? (or I'm on the wrong way!?)

essence

ATX power supply ?! That's crazy, especially if you don't know what you're doing, did you even check if the ATX has the same Ampere strength as the regular power supply ?

Check this thread : http://sp1200.myfastforum.org/sut....php&highlight=capacitor#1134

and use the search function with the term capacitor!