Rapair of the Power Supply

As an alternative to replacing the power supply.

A tip I got from Daniel Hrdina

danielhrdina at googlemail com

Hello Henrik,

With the help of the scheme on macbidouille.fr I could manage to find the IC FSDM0265 by Fairchild semiconductor as one of the problem sources on the power supply board. Luckily, RS-Components, a electronics distributor in UK and Germany, has the successor of the old DM0265RN IC used in the older APX in their program. Fairchild themselves call the new Q0265RN the direct successor which is fully compatible with the DM0265RN and the sometimes used DH0265. They can be bought in a pack of five for around 8,40€ incl. tax which is nothing compared to a new APX ;) My first try with the new IC showed a yellow LED! The device was booting up. But unfortunately my attempt was stopped by smoking resistors. I figured out that these resistors are mostly the source of the burnt IC board surface that can be seen on several articles and blogs regarding the broken APX. At work we have a device to measure inductance so I tried to figure out, which coil was needed. I found this one to almost match the original specifications
It is not so critical to have a little higher resistance in the inductance because it just helps the FSQ IC a bit with his work. The inductance shall just filter and smoothen the current but in general the IC should be capable of it too. So maybe you would like to put these informations on your blog. Now, the APX runs as ever before, it works fully properly and at the moment I'm listening music through it ;) So to sum up my found information: The FSDM0265/FSDH0265 can be replaced by the fully compatible FSQ0265 The inductance (the green part with the 222 printed on it) has the following spec: 2,2 milli Henry @ 6 Ohm (can be replaced with 2,2mH@8,8Ohm in 07P form factor)

Greetings from Germany
Daniel

And a followup!

Hi Henrik,

sorry that I didn't answer sooner but I was quite tied to my work in the last couple of days. Driven by your hint with the capacitors, I checked them just to go for sure that all parts of the power supply are okay and guess what!? One of the big caps (400V, 10µF, 105°C) was dead. Or at least it had just 3,5nF capacity where the other one is still okay. I ordered a new one to replace it and even though I could not find a capacitor with the exact size I found one with the similar diameter and just 3mm more in length which fits into the case of the APX without any problem. According to that it seems that your suggestion was absolutely correct and that the capacitors seem to be the source for all of the seen consequences with either burnt ICs or the coils...

It is exactly like in the video...a replacement of parts worth around 5€ solves the whole problem instead of buying a whole new device for more than 80€...and the whole world is talking about preserving resources...

Kind regards,
Daniel

Hello Henrik,

so I got finally my last part, the capacitor, and now it works just fine again. I made some pictures which show the parts I've changed, the parts I unsoldered and I gave you a closeup of the Fairchild IC and a total view of the running and blinking APX.

If you'd like any further pictures, feel free to contact me.

Kind regards,
Daniel