Right. The XP-50. I bought this one a few months ago. The problem with this one is that it only produces a loud static noise.. powers up just fine and the display also works fine. Time to open it up 🙂 Because XP-50’s are prone to failure there is a lot of information available online. The display seems to be the biggest issue but there are numerous problems that all boil down to this: leaking capacitors. The XP-50 is 20 years old and the mainboard contains 27 electrolytic SMD capacitors that unfortunately go bad over time. They cause all kinds of problems and the display is normally the first part that stops working. When that happens the display will light up (orange) just fine but it won’t display text anymore. This is caused by 3 capacitors that are broken in that case. Other problems are no sound or distorted sound etc. There seems to be a pretty high succes rate when you replace all 27 capacitors so I though I give that a try 🙂 I opened up the XP-50 and disconnected all the wires so that I could take out the mainboard:
The round silver thingies are the culprits:
Since they are SMD parts (surface mounted parts) it means that removing them requires a SMD soldering workstation. Which I don’t have. I’ve read online that twisting them off with a pair of small pliers works fine if you’re carefull so I though I’d give that a try:
Surprise 🙂 they come right off! Very easy. After that carefully remove the black plastic parts that remain on the PCB and then comes the tedious part of desoldering the pins. I could now see that a lot of the capacitors have leaked. This is very difficult to see when the capacitors are still on the board. I removed all the remaining pins from the PCB and then used desoldering wire to remove the old solder. When desoldering a very corroded pin doesn’t work add some fresh solder and it will come off without a problem. After that clean the PCB with q-tips and alcohol to remove any leaked electrolyte.
I’m going to replace the caps with regular through-hole electrolytic capacitors because I can solder those on with a normal soldering iron. I’ll try to finish it next week.
Update june 2nd 2015: I’ve replaced all caps but the problem remains :’) I’ll check some things later..
Update june 8th 2015:
I’ve removed all the new caps and cleaned the PCB again. I also checked all the traces going to and from the pads leading to the caps and I found one open trace. I repaired this and soldered all the caps back on. I reinstalled the mainboard and switched the XP-50 on: still the same problem :’) Only loud crispering static noise.. I’m not going to be able to fix this. I’ll probably sell it for parts or as a ‘for parts’ XP-50…
I have an old worn dirty JV-80 waiting for some desperate TLC in the attic. Moving on 🙂