The leakage is very bad, as expected. You will need to clean all the acid off the board. 1. Remove all old capacitors, use the hold base and twist top method. Desolder the legs best you can. 2. Wash the board with baking soda paste and distilled water. Let the paste sit for about 20 mins. 3. After rinsing with distilled water, 91-99% isopropyl alcohol. 4. Dry it with a hairdryer, not too hot. Let sit for at least a couple hours before applying power! 5. Fix any damaged traces. Re-cap. If there is any corroded solder left over that can't be desoldered, scrape off with a flat screwdriver and clean the area with alcohol. 6. Add small amount of Deoxit to the switches, volume pot, gold contacts.
I have got the caps off, and taken some isoprop to the board. It'll sit there until the new caps arrive from DigiKey next week. In the mean time, I've got to get some practice in on the SMD training kits I bought. I'll be getting to grips with them tomorrow. However, the one thing they won't prepare me for, is the close quarters that these caps are in. Tight work. I'm fully expecting this P505 not to survive this. That's why I bought them... practice. I don't even have a service manual for this one. It will be a miracle if this first unit works when I've put it back together. Fortunately, I think I've got away with the traces. They're all good from what I can see. The Deoxit... I didn't think of that. I'll get some on order.
Thank you @bub for this perfect procedure! Let me put the emphase on point number two: It is the most important indeed when the aim is to properly salvage the board of an Aiwa walkman, as the acid is not affected by alcool (isopropyl or whatever). The baking soda is a light base, in big amounts it is able to neutralise the very strong acid that leaked (in comparatively lower amount) from the capacitors. If not properly neutralised this acid will of course continue to ruin the board after the "repair" attempt.
Is there any way to bring back a board from the dead? I didn't neutralise the acid in my pc202 and it just stopped working. What do?
The acid may have electrical properties which would lead to shortcuts, thus preventing the board to function properly. And of course the chemical properties of the acid do consume the board and the traces in the long term. On Aiwa hi-ends like the PX and JX series, which provide some "logic" functions, those functions also can suffer from shorts or dead traces, not only audio. So yes, neutralising the acid by the proper cleaning described above can sometimes be enough to bring a player to life. If it's not enough, you will have to verify continuity on all traces. Your PC202 doesn't have logic commands: what do you mean when you say it just stopped working? Some videos and photos might help us to give the right advice.
