Polymer bulk cap in an Atari 2600?

[jayjr1105]

Scored a Vader 2600 in pretty good condition. I'm going to do all the recommended cap replacements all around and have a kit from console5.com on the way including a 5v regulator. I just remembered I have some 2200uf 16v Kemet Polymer caps that are very small and should be able to mount vertically. I'm considering using it as long as the polymer won't cause problems where an electrolytic axial one was before. Is this okay to do?

[petehall347]

Re: Polymer bulk cap in an Atari 2600?

polymer is electrolytic

[redwire]

Re: Polymer bulk cap in an Atari 2600?

Oriiginal is a linear power supply, 9VDC 500mA wall wart feeding 2,200uF 16V axial 7805 voltage regulator.
IMHO a polymer cap is overkill ESR=10mohm and not needed for the mains frequency ripple. The 7805 isn't affected by the low ESR, so it's OK to put one in if you want. Power switch on surge will be big and sometimes that causes destructive spikes.
Mains sags would make the game crash sometimes. But the (original linear) wall wart also has a big filter cap inside. Without that, I would upsize the 2,200uF cap to whatever fits. Coleco had 10,000uF in their psu.
I'm not sure if people are using SMPS wall adapters with 2600 and their tons of RF noise.

[jayjr1105]

Re: Polymer bulk cap in an Atari 2600?

Oriiginal is a linear power supply, 9VDC 500mA wall wart feeding 2,200uF 16V axial 7805 voltage regulator.
IMHO a polymer cap is overkill ESR=10mohm and not needed for the mains frequency ripple. The 7805 isn't affected by the low ESR, so it's OK to put one in if you want. Power switch on surge will be big and sometimes that causes destructive spikes.
Mains sags would make the game crash sometimes. But the (original linear) wall wart also has a big filter cap inside. Without that, I would upsize the 2,200uF cap to whatever fits. Coleco had 10,000uF in their psu.
I'm not sure if people are using SMPS wall adapters with 2600 and their tons of RF noise.

Yes I figured polymer and even name brand wet electrolytics would be overkill in this use case but just wanted to make sure there would be no adverse affects from using a capacitor of different chemistry. Since you say raising the capacitance would be a good thing. the 2200uf 16v poly's I have are so small, I might mount them upright traditional through hole style and bodge in the wires underneath the board so they're parallel.

[jayjr1105]

Re: Polymer bulk cap in an Atari 2600?

It's a bodge for sure but at least a clean one.