Hello all,
This is a pictorial about a repair of a Sony HB-F1XDJ I recently did. The owner (Meits) turned her over to me with the symptoms being described as unwilling to turn on sometimes and issues with some keys. After a short testing I confirmed that yes, she didn't want to turn on (boot) sometimes, and if she booted, things weren't stable for long and there were erroneous key presses, like EF appearing when E was entered.
So after a quick undressing the motherboard was put on the workbench for inspection. Knowing the HIC module was suspect I removed the FDD and gazed.. behold:
The red line indicates the affected area with electrolyte leakage. *_*
But there was more..
A leaked 10uF through hole capacitor :o
Bottom side of that area and it has leaked through oO
Another one oO
And bottom..
Another one oO
Aand another one oO
It appears that on this unit all capacitors of one brand and one value had leaked. All 4 of the ELNA 47uF / 25v ones had leaked. They had lost all electrolyte and all capacitance, my ESR meter couldn't make head or tails of them anymore:
So much for the diagnosis. Replace caps and clean the PCB! Onward to the happier pictures :D
SMD caps desoldered and area cleaned. Desolder with hot air, clean with isopropyl alcohol. I also used some vinegar to neutralize the electrolyte (base). Scraped off the pads to remove additional corrosion.
New shiny caps installed! Use some good smd soldering flux to make things easier. Fun fact: these are Panasonic caps in a Sony MSX :)
More area cleaning and new caps:
As a bonus, removed the empty and redundant CR2032:
I decided to replace all of the electrolytic capacitors on the board that were ELNA branded, as they are suspect, even if they are different values. The rest of the caps were Nichicon branded, no need to change those they are top notch premium quality and should last for another 25 years.
Sure enough the MSX2+ is happy again. She boots every time now, and is back to rock solid. There was some corroded copper, but no traces that had to be repaired. This makes me believe that one of the 4 busted through hole caps was part of some timing circuit, because missing decoupling caps should not affect the system that much. The caps on the HIC board were only serving the rgb to composite circuit, normal rgb was unaffected since it passes through the module, far away from the leaking caps.
I would advise other HB-F1XDJ owners to check their machines for cap leakage and the ELNA branded caps and have them serviced, before serious damage occurs. Broken traces means labor intensive trace repairs and thus more expensive repairs. Even if your machine is OK now it would be wise to do it preventatively!
Cheers
Omega
. 
