Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

[Y. Signal]

Hello. I have a Sega Mega Drive model 1 VA6 (it's the same as Sega Genesis) that I plan to recap to improve the sound that, although good, it's not great as other board of the same revision I own.

After much reading I've come to the conclusion that I need high quality capacitors with low ESR (but not too low) from a trusted provider. I bought Panasonic FC but I couldn't find the 1uF 50V neither 1uF 100V, so I got Rubycon ML 1uF 50V, are these ones good for this board? they're general purpose, low ESR and suitable for audio/video according to the provider.

I've been recommended to replace the 7805 regulators that come with the board since the original PSU is linear and it's not very good. I've checked the regulators under load and they give 4.99-5.01V so I'm not sure about changing them since they are working apparently fine.

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

the regulators are fine,
and any caps will do, but in future if you need to do this:
1uf and 2.2 uf you can use rubycon YXJ
higher values i use panasonic FR

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

Thank you so much, the next time I'll use those. I've recapped my console with Panasonic FC and Rubycon ML (16V instead of 10V) and it went fine, now the sound has more "punch" and it's no longer muffled . I can hear new sounds in some games.

This is the list of electrolitic capacitors (IC BD M5 PAL VA6):

• 6x 1 uF 50V
• 13x 10 μF 16V
• 7x 47 μF 10V
• 7x 100 μF 10V
• 1x 100 μF 16V
• 3x 220 μF 10V
• 1x 220 μF 16V

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I'm looking for Panasonic FR 10uF 16V but the closer ones I can find are 10uF 50V, is it ok? do they fit without problems in the Sega Genesis/Megadrive model 1?

[RukyCon]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

It should be OK to put 50v caps in place of the 16v capacitors.

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

no problem.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

Thank you so much for your help.

I've already ordered some Panasonic FR and Rubycon YXJ to recap some more Mega Drives. My favorite of them has hanged with some games so I'm planning a recap. Is it true that using the console with so old capacitors might be damaging important parts of the circuit, even if it's working apparently fine?

Has anyone measured the possible oscillation due to using so low ESR on these circuits? I've read the recommendation of not using capacitors with lower ESR than Chemi-con KY, Rubycon ZL or Nichicon PM for Sega Genesis in this forum so I'm a bit confused about what's the safest option taking into account that the console circuit may have been built around the old capacitors ESR... or is this another case like in the ZX Spectrum, where using this low ESR caps is safe?

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

low esr can only cause problems on the output of regulators, but the type in stuff like megadrives wont care.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

Great, I'll use those caps. Thank you again.

[mockingbird]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

Rubycon ML is a fine choice. It's GP, but high endurance GP. I think its equivalent would be Panasonic EB, but Panasonic seems to have (or is in the process of) discontinuing EB for some reason.

[RJARRRPCGP]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I can hear new sounds in some games.

That reminds me of Nintendo 64 emulation with a particular game, Goldeneye, from good ol' Rare! Starting with the PJ64 1.0 RSP emulation plugin, IIRC, I would hear music effects that were clearly missing with most implementations of Nintendo 64 audio emulation. Goldeneye seems to be very unique for requiring a feature of the RSP for some audio effects of music...

Ironically this is more expected with the SNES, because of folks clearly alleging being unable to find documentation for the SPC-700 chip. (from Sony, IIRC) So I thought I saw someone write why audio portions are missing from ClayFighter, IIRC.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I have recapped another Sega Mega Drive PAL VA6 with success, this time using Panasonic FR and Rubycon YXJ for the lowest value.

Initially I had a problem after ~50min usage. The image turned a bit wavy in spite of being connected through RGB, so I supposed that was related to heat and then I thought about flux residues... so I cleaned the bottom of the board using IPA 99%, let it dry and the problem dissapeared I've tested it during 3 hours or so.

The image looks very nice and the sound is very good. Thanks again for your help! this forum rocks

Post Update: this problem has just appeared again. I'm not fully sure if this has to do with the recap because I possibly did not test this console long enough before.

There were two solenoids in contact, I've separated them and I'm going to make sure that capacitors next to the video encoder are not in direct contact with the heatsink.

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

test with the case open, it could be something heating up.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I think so, it ran fine during three hours with the case open. I have not tested other consoles but I'll test the next one before and after the recap.

Temperature has gone up here so I'm considering to use a fan and leave the case open during the summer.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I've been using this console during some hours, with the case open and it works perfectly. I've not noticed any abnormally hot chip except the 7805 regulators and the heatsink, which are attached using arctic silver ceramique 2 thermal paste. I've not touched the video encoder to avoid removing the heatsink again abusing the legs of the 7805s.

These regulators are marked as "L7805CV ST 99205". I think it's normal for them to run so hot but I'm not sure. The PSU I'm using is Ideal Power HK-AW-090A167-CP (9V 1.67A).

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

they will run very hot.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I've recapped my other Sega Mega Drive and I've noticed exactly the same video problem after using it during one hour approximately. I've run another Sega Mega Drive with stock capacitors during 2 hours and it does not present this problem.

Is it possible that the new capacitors with so low ESR may increase the heat produced by the 7805 regulators? tomorrow I'll replace the Panasonic FR in one console with Panasonic FC to check and I'll post the results of the experiment. For now I'll keep the Rubycon YXJ since they're not so low ESR.

[Sparkey55]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

I've been using this console during some hours, with the case open and it works perfectly. I've not noticed any abnormally hot chip except the 7805 regulators and the heatsink, which are attached using arctic silver ceramique 2 thermal paste. I've not touched the video encoder to avoid removing the heatsink again abusing the legs of the 7805s.

These regulators are marked as "L7805CV ST 99205". I think it's normal for them to run so hot but I'm not sure. The PSU I'm using is Ideal Power HK-AW-090A167-CP (9V 1.67A).

The 78 and 79 series regulators do run hot normally but can only sink about 1 to 1.2 amps max and need about 2 to 2.5 volts above the output voltage to work correctly. otherwise they shutdown as a protect mode. If you have the room and a large enough heatsink you could try the LM7805K series, these are in TO-3 case style and can handle up to 3 amps.

[stj]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

an interesting modern upgrade would be to replace the 7805 with a 3a switching regulator module - those things hardly generate any heat.

[Y. Signal]

Re: Will the Rubycon ML capacitors do the trick for a Sega Megadrive (Genesis)?

The console has been recapped using Panasonic FC and Rubycon ML and it works perfectly after nearly two hours working.

I've read about experiments replacing the 7805 with a switching regulator in consoles and the result was not good due to noise. I'll take a look at the LM7805K, thanks.