Exchange of electrolytic capacitors Master System II – Tec Toy

In 2015 shown here in Skooter Blog Tec Toy Master System II acquired, exactly the same model that I had as a kid. It worked fine for about four years, but after that it started to present a problem: to turn it, did not appear picture and sound, only the Power LED is lit and the image on the TV gave a wink.

It was necessary to leave it on for a few minutes with no picture and no sound, until he finally ran. Then the SEGA logo appeared, but he was still in restarting loop a little longer to load the game. After “heat” it worked normally, can turn it on and off you will, including the following days. The problem only appeared when he stood a long time.

Logo suspected of electrolytic capacitors, but I have been putting off the repair, for lack of time and because of trauma because of what happened with my Super Nintendo.

Until last week I decided I would do myself the service. First let the connected source enough time disconnected from the console to see if the problematic capacitors were hers or console. When connecting the already hot spring on the island it did not work, then I delete the source I concentrated on the island.

I consulted colleagues from Community Master System on Facebook to see if anyone had any guesses beyond the electrolytic capacitors, but colleagues also pointed only capacitors and voltage regulator as a possible cause of the problem.

I then decided to dismantle the Master System II to see if there was some stewed capacitor or leaked to facilitate my work. But unfortunately they were all looking good. I could not bet on any of them specifically.

I saved any screws, and separate indication of where left. You know those guys that leave things open anyway? Losing screws and the end can not ride again? That lay screw longer where it should not bursting all plastic holder? End mounting screws with left and throw away? Do not be that guy! I hate when I buy something, I open and see these aberrations. Always put the screws into place.

Check out the photos:

so I wrote down the value of all electrolytic capacitors. The PCB has the inscription TEC TOY POWER BASE / PAL-M 1989 199-403-411-416 Rev. X and 18 electrolytic capacitors I found were these:

  • 2x 220μF 50V (C50, C56)
  • 1x 220μF 25V (C53)
  • 3x 100μF 25V (C43, C46, C41)
  • 3x 22uF 25V (C20, C21, C22)
  • 8x 10μF 50V (C7, C5, C13, C45, C2, C9, C15, C14)
  • 1x 10μF 16V (C16)

The voltage regulator is a 7805CT MC J9048.

Note that these are not necessarily the original console components. It is possible that he has already undergone repairs and that he has changed something. But in the absence of more information, I bought the components from that list.

I found all the items in the local store, but some capacitors I had to buy with higher voltages, as they were not available at the exact voltage. In the purchase I already placed one item more than each component, including voltage regulator, in case some come defective. I Spent R$ 12,00 no total.

I started replacing the capacitors closest to the voltage regulator. First I removed the C50, from 220 μF 50V. Making the measurement he indicated:

  • Capacitance: 216.8 μF, ESR: .00 ohms, vloss: .6%

Capacitance as expected, in any way I put a new measuring:

  • Capacitance: 222.6 μF, ESR: .02 ohms, vloss: .3% ~ .6%

I tested the console and saw that this change did not solve the problem.

I went to the next capacitor, o C53, also 220 μF 25V. After removal, measurement he presented:

  • Capacitance: 211.8 μF, ESR: .06 ~ .07 ohms e vloss: .9%

Again as expected. Replace with a new one indicating:

  • Capacitance: 213.2 μF, ESR: .04 ohms e vloss: .9%

I tested the console and again did not solve the problem.

The next to be changed was the C7, from 10 μF e 50V. This rather strange measurements presented:

  • Capacitance: 33.08 μF ~ 39.69 μF ESR: 1.5 ~ 2.5 ohms, vloss: 3.9% a 4.9%

Medi several times and really capacitances were well above expectations. I put a new, indicating:

  • Capacitance: 9679 nF, ESR .39 ohms, vloss: 1.0%

Nevertheless, the island did not return to work.

then exchanged two capacitors 10 μF e 50V, C5 to C13, which are very close to the crystal oscillator. They also indicated much higher capacitances that should:

  • C5: Capacitance: 37.66 ~ 38.10 μF, ESR: 1.4 ~ 1.9 ohms, vloss: 3.6%
  • C13: Capacitance: 41.66 μF, ESR: 1.5 ohms, vloss: 4.4%

I put two new capacitors with the following measurements:

  • Capacitance: 9817 nF, ESR: .47 ohms, vloss: 1.1%
  • Capacitance: 9736 nF, ESR: .41 ohms, vloss: .8%

Bingo! After these exchanges called the Master System II, and the SEGA logo appeared immediately and soon began Alex Kidd in Miracle World, one of the best glorious games console 8 bits, and coming in the memory of the Master System II.

You could stop there, but I was suspicious of capacitor 10 μF e 50V. Of three, the three were defective, it's likely that the other five of the same make and model were also. They are all from Siemens, in orange, show “10 μF (M)”. The letter M indicates a tolerance of +/- 20%. But the values ​​observed came easy +300%! All these capacitors had the number 85049 signed up.

I then decided to change the five missing and, although the island is already running, four of them also had strange measurements, only one was with the capacitance within the normal range. Check out:

  • C9: Capacitance: 41.02 μF, ESR: 1.6 ohms, vloss: 3.7%
  • C45: Capacitance: 10.23 μF, ESR: .86 ohms, vloss: .7%
  • C12: Capacitance: 22.53 μF, ESR: .93 ohms, vloss: 2.0%
  • C15: Capacitance: 25.28 μF, ESR: 1.7 ohms, vloss: 2.7%
  • C14: Capacitance: 38.10 μF, ESR: 2.4 ohms, vloss: 4.6%

All were exchanged for new capacitors with capacitance correct.

For future reference, I think it's also important to note that the capacitors with above normal capacitance also presented vloss high, all above 2%, while capacitors with capacitance as expected showed vloss below 1%.

I decided not to move in the other capacitors, since only these Siemens presented incorrect measurements, and that the rest of the electrolytic capacitors were probably ok, such that the first two being removed, da marca Alltech.

I understand that those who make exchange of commercially already enjoy capacitors to switch everyone to avoid returns under warranty. But in my case, I can always open the console again if necessary, then I did not see need to move the items you were running without causing problems. Remove components always involves some risk to the plate, even if those who are doing not have much experience, as is my case.

Here then is the balance of exchange, removed with three capacitors that were apparently ok, seven defective, although not all were causing apparent problems.

And this is the board after the exchange of capacitors:

then I took to make a good cleaning with isopropyl alcohol, leaving the well quite clean plate:

thermal grease still switched to the voltage regulator. I ended up using a Arctic Silver 5, which is certainly an exaggeration, but it was the only thermal grease I had in hands. I forgot to buy some more common folder when I was in the electronics store. Por fim, I passed a new veneer on the board, to protect the new welds.

It is important to trim all welds, Terminal high components, etc. so nothing touches the metal protection system. In my pictures still had some ups components, trimmed prior to closing. I should have done before applying the varnish.

After all this shut the console and decided to clean it out too, applying a plastic revitalizing to leave it beautiful like new:

And linking the island he has worked out of the, as expected. I let it run for a few hours, no problem:

Check out the video with some images of the procedure:

I will now leave the console off for a few days to make sure that the problem really was. And so I hope my Master System II run for many more years free of problems.

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Bem legal o artigo. O meu eu mandei instalar mod rgb, já que a tectoy cagou bem usando a saída múltipla do console para powervai entender o que eles tinham na cabeça na época. Aí o sujeito já deu um banho e trocou os capacitores. Mas legal ver o seu trabalho de fazer você mesmo.

Gabriel R.

Bom reparo e, mainly, ótimo relatório. Tenho um medidor de componentes similar e tinha o mesmo tipo de dúvidas.

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