Sony HB-F1XDJ capacitor leakage repair guide

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By Omega

Master (230)

Omega's picture

21-12-2017, 00:08

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

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By hamlet

Scribe (3623)

hamlet's picture

21-12-2017, 00:13

Nice job! Another MSX rescued from death. I´m sure the Sony wouldn´t mind the Panasonic components.
And thank you for sharing!

By Grauw

Ascended (10004)

Grauw's picture

21-12-2017, 00:25

Yikes! Good job bringing one MSX back from the dead!

I made a wiki page about MSX models (with links to the respective topics) which have dangerous capacitors and/or batteries in them, I only remembered one other thread but I’m sure there are others too, and I hope others will add to the list.

By Meits

Scribe (6430)

Meits's picture

21-12-2017, 00:32

Eternal thanks. I'd be sad for a long time if this was going to be a static model for the rest of my life.
On top of all expenses covered you know what the bonus(es) are :)

By Meits

Scribe (6430)

Meits's picture

21-12-2017, 00:34

Grauw wrote:

Yikes! Good job bringing one MSX back from the dead!

I made a wiki page about MSX models (with links to the respective topics) which have dangerous capacitors and/or batteries in them, I only remembered one other thread but I’m sure there are others too, and I hope others will add to the list.

Apologizes in advance gdx and frs (somehow I always mix up both of you, what if one of you would only be called sd_snatcher ;) ). One of you two has once listed a few suspects in the forums.

By Omega

Master (230)

Omega's picture

21-12-2017, 00:35

Typo correction: the original ELNA caps are 47uF / 6.3v. (I installed Panasonic 25v 105c ones, way overspecced but it's a MSX!)

Also, I wish there were schematics available for the HB-F1XDJ. I'm used to working with schematics and board view software and without those it's just guessing (or a lot of reverse engineering) what something does..

And forgot to mention the keyboard works without issues now.

Also, if you're not confident enough to do it yourself I'll recap your F1XDJ for 20€ plus shipping.

By gdx

Enlighted (4626)

gdx's picture

21-12-2017, 12:43

Grauw wrote:

I made a wiki page about MSX models (with links to the respective topics) which have dangerous capacitors and/or batteries in them, I only remembered one other thread but I’m sure there are others too, and I hope others will add to the list.

You can add FDD belt. I think the capacitors problem is more general.

By Grauw

Ascended (10004)

Grauw's picture

21-12-2017, 13:12

I think FDD belt is more of a common failure, rather than something you need to "watch out for", or something you can take precautionary measures for. The wiki page is not a "common problems repair guide", but rather "watch out for this stuff and avoid damage". I don’t know what precautionary action you could take to prevent it, and it’s not really dangerous either.

But maybe even though it’s slightly out of the scope that I had imagined, it’s ok to list specific models where the FDD belt breaks down particularly quickly. Either way, I’ve given you my thoughts on this, it’s a wiki page so now feel free to edit it to your liking Smile.

By Alexey

Guardian (3159)

Alexey's picture

07-01-2018, 19:35

Just replaced the 3 capacitors on the daughterboard of my F1-XV. There was no leak so far, but better to be safe than sorry later. The 10uF 16v size B tantalum capacitors fit just perfectly. The 100uf 16v size D tantalum capacitor was a bit more challenging to install, but it also fit quite nicely. Thanks for the warning about those caps. Similar ones almost killed my Sega GameGear last year.

I also replaced the long dead clock battery by desoldering the old one from the board and installing the 2032 size plastic socket instead.

By Josevil

Master (194)

Josevil's picture

16-02-2018, 19:05

the retired capacitors are 4.7nf and 6.3v. those of 25v will work correctly?

By Alexey

Guardian (3159)

Alexey's picture

16-02-2018, 23:52

Yes, bigger voltage rating is not a problem. Unless the size matters...

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