35 replies to this topic

[0078265317]

So it works now?

Edited by 0078265317, Tue Jun 28, 2011 11:55 AM.

[eightbitter]

Rod, do not give up so easily. When 5200 stopped working after assembling, it is probably shortcut on the port expansion circuit (rear left). Check that this connector does not shortcut by RF cover. When, after removing the RF cover still does not work check if there is a warm any little chip 74xx, or RAM and replace it.

Edited by eightbitter, Wed Jun 29, 2011 5:42 AM.

[Rodrigo]

0078265317, on Tue Jun 28, 2011 11:55 AM, said:

So it works now?

In fact, I'm just waiting for the parts arrive for assemble it again. I live in Brazil.

eightbitter, on Wed Jun 29, 2011 5:42 AM, said:

Rod, do not give up so easily. When 5200 stopped working after assembling, it is probably shortcut on the port expansion circuit (rear left). Check that this connector does not shortcut by RF cover. When, after removing the RF cover still does not work check if there is a warm any little chip 74xx, or RAM and replace it.

Eightbitter, thanks again for your advice. I decided to change those parts (well... that's almost everything) after doing a lot of testing (First Zylon, then Best gave me suggestions, but before that I did test it by myself). I looked very carefully at the rf shielding, and to the expansion port, and found nothing. Regarding to the IC's, all of them remain cold (that's not strange, since I have 0 volts at the voltage regulators). With the Zylon advices, I even changed a few components that usually cause problems (voltage regulators, some transistors and capacitors). Even then, nothing happenned.

[zylon]

Start testing the diodes in the power in and out lines on the board. A failure here would cause a no-power issue. You mentioned earlier having power up to one of them.

[Rodrigo]

zylon, on Wed Jun 29, 2011 1:01 PM, said:

Start testing the diodes in the power in and out lines on the board. A failure here would cause a no-power issue. You mentioned earlier having power up to one of them.

Yes, you're right. But after that diode, I simply couldn't find what's wrong. I don't have enough knowledge in electronics, so I tried a "dumb" parts replacement (the usual suspects, and some mentioned in that Atari Field Service Manual). No luck. From the topic named "snowy screen", following the chart, the only parts I didn't replace was the A26 IC (since it's custom) and those BD like transistors.

[zylon]

Rodrigo, on Wed Jun 29, 2011 2:15 PM, said:

zylon, on Wed Jun 29, 2011 1:01 PM, said:

Start testing the diodes in the power in and out lines on the board. A failure here would cause a no-power issue. You mentioned earlier having power up to one of them.

Yes, you're right. But after that diode, I simply couldn't find what's wrong. I don't have enough knowledge in electronics, so I tried a "dumb" parts replacement (the usual suspects, and some mentioned in that Atari Field Service Manual). No luck. From the topic named "snowy screen", following the chart, the only parts I didn't replace was the A26 IC (since it's custom) and those BD like transistors.

Is that IC socketed on your board? I have a junk 4 port, that I use for parts. It still powered up so those parts would still be good.

[Rodrigo]

zylon, on Wed Jun 29, 2011 2:45 PM, said:

Rodrigo, on Wed Jun 29, 2011 2:15 PM, said:

zylon, on Wed Jun 29, 2011 1:01 PM, said:

Start testing the diodes in the power in and out lines on the board. A failure here would cause a no-power issue. You mentioned earlier having power up to one of them.

Yes, you're right. But after that diode, I simply couldn't find what's wrong. I don't have enough knowledge in electronics, so I tried a "dumb" parts replacement (the usual suspects, and some mentioned in that Atari Field Service Manual). No luck. From the topic named "snowy screen", following the chart, the only parts I didn't replace was the A26 IC (since it's custom) and those BD like transistors.

Is that IC socketed on your board? I have a junk 4 port, that I use for parts. It still powered up so those parts would still be good.

I'll check later and inform you.

[zylon]

I'm going to do a little research on that IC. Not sure if 2port is different, but that should be a standard chip.

Edit: Just buy one, they're super cheap.

eBay Auction -- Item Number: 120714387329

[Rodrigo]

zylon, on Fri Jul 1, 2011 11:29 AM, said:

I'm going to do a little research on that IC. Not sure if 2port is different, but that should be a standard chip.

Edit: Just buy one, they're super cheap.

eBay Auction -- Item Number: 120714387329

I tought they were custom because of the 5200 field service manual. In the parts listing or other place (if I'm not wrong) says it's custom. It's good to know they aren't. And wow! They're really cheap. I just bought some (3 - just in case). Now, it's just wait for them. Oh, and thank you again for your research, Zylon.

[zylon]

Cool.

I've looked in 4 systems(all 4-port though) and all use the same chip, just by different manufacturers. 3 were socketed, 1 was soldered.

[Rodrigo]

Well, I'm updating this topic after a long time, but I think it's cool to know the conclusion of the questions posted. First, I've received the parts that I ordered from Best Electronics (it was cool, the motherboard came sealed in a plastic bag with a tag with atari logo in it), and then I replaced the original motherboard and power adapter. As Brad said, it worked just fine . Then, after a looong wait, I received the IC's that Zylon found could help my original motherboard (they came from China). After another waiting time (well, I was playing my new 5200...), I decided to give one more try at the original motherboard. So I removed the original IC and put the new one and... it worked! Too bad that after a few testing, it won't start again . But this time I noticed that the original power supply was abnormaly hot. Then I replaced it for the new one that came from Best, and it just worked again. So now I have a complete 5200 plus another working motherboard, just in case... Thanks for everybody and specifically Zylon, for help.