Recap recommendations

By siddy6581

Expert (84)

siddy6581's picture

23-06-2018, 10:28

Hi there!
I'm a happy owner of one Philips NMS 8250 MSX2. Unlike my other machines (C64 and A1200) this one has never been recaped. I was wondering what you're recommendation are concerning recapping NMS-machines? Should you do this as soon as possible and what are the possible benefits? I've once heard that the NMS-machine have particulary good capitatorts which last very long, is this correct?

Is there anywhere you can buy recap-kits or find list of all the capitators needed for NMS-models? Is recaping on the NMS more complicated than other machines?

best wishes /Siddy

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By Wlcracks

Master (146)

Wlcracks's picture

23-06-2018, 11:06

If the machine is made in Japan leave it lol. Just Smell and look for leakage on the board. Use Rubycon, Chemi-Con, Nichicon or Panasonic. Changing to made in china caps will just make the machine worse. My Philips MSX are all fine.

By Alexey

Paragon (1564)

Alexey's picture

23-06-2018, 13:38

Some of the 30 year old caps in my Yamahas show better results than the freshly-made chinese ones, hehe...

By RetroTechie

Paragon (1434)

RetroTechie's picture

23-06-2018, 14:09

After 30+ years even good caps may have dried out or otherwise perform poorly. But, if you look inside a homecomputer like MSX, electrolytic capacitors fall apart in several categories:

a) Those used for power supply bypassing on various pcb board sections (around 10-1000 uF range, spread out over a circuit board). Even if you cut those out, machine will often keep working fine(!). So why bother going over a board to replace a bunch of 'em?
b) Various caps in analog audio / video circuitry. Depending on what inputs & outputs you use, you should be able to hear or see (screen image) if those are failing. If not, there's no problem even if they aren't doing their job well.
c) In main power supply. It wouldn't hurt to replace those caps anyway regardless of condition. Also a good opportunity eg. to replace hot-running diodes with a beefy bridge rectifier that's screwed to the case. Or pop in a new 7812 / 7912, beef up a heatsink, re-apply cooling paste or similar measures.

Wlcracks wrote:

Use Rubycon, Chemi-Con, Nichicon or Panasonic.

+1. And buy from respected distributor like Farnell, Mouser, Digi-Key etc, or smaller shop that buys their parts directly there. If you cheap out on eBay & co, good chance you'll either get low quality crap, old stock (that sat 5, 10 or 20+ year on the shelf), or even fakes.

So in main power supply: good idea to re-cap. Outside of there, not much point unless you spot issues.

siddy6581 wrote:

Is there anywhere you can buy recap-kits or find list of all the capitators needed for NMS-models?

Service manual has a parts list, compare with what you find on actual board. Schematic can tell you what function each cap has.

Quote:

Is recaping on the NMS more complicated than other machines?

Nope, just many screws between you & main board. LOL! And I prefer replacing caps 1 by 1 - less chance of mixing up values, inserting with wrong polarity etc.

By siddy6581

Expert (84)

siddy6581's picture

24-06-2018, 12:08

Thanks for all the recommendations. Yes the NMS says "Made in Japan" on the back side. I've opened it a few times and checked most of the motherboard (didn't want to screw loose the graphic top board) and all the other parts. No fishy stuff going on, or leaky battery as far as I can tell. I've installed a second disk drive and the first drive is also replaced by the previous owner, so the computer might have been serviced before.

I guess my first recap would be the PSU-section, it tends to become a little warm during use (but not too warm)
...but for the moment that can wait, this machine works great Smile

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