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I've never seen anything like this...


DavidMil
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I just received a 5200 I bought on ebay. The description was a dead 5200 (for parts). It looks like someone without much soldering

skill tried to do some sort of upgrade. I'm not that familiar with 5200 upgrades and I have no idea what this person was trying to do.

Here is what I am seeing:

1st: I see that the trace between C61 and the power has been cut and a diode has been installed. (picture 1)

2nd : I see that pin 11 of the GTIA chip has been raised. (picture 2).

3rd: I see that a wire have been installed between A27 pin 3 and the raised pin 11 of A15. (picture 3)

4th: I see a wire that connects A27 pins 1 and 2 (these 2 pins a connected by a solder bridge) to the A2 pin 3 (CPU) and pins 9 and

12 on A14. (picture 3)

 

What ever this mod is supposed to do, it vaporized part of R53 so it's no wonder the unit won't power up! Anyone have any idea what

this person was trying to do?

 

Thanks,

DavidMil

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Edited by DavidMil
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It's from the factory. I've had several boards with the pin lifted.

 

Are you saying you've seen this mod with the two wires, or just the lifted pin on the GTIA chip? I agree that the trace cut on the underside for

the diode looks professional, but the soldering on the wiring looks very amateurish. Plus I've never seen stranded wire with such thick insulation

used for a factory modification.

 

DavidMil

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I was going to say, the Diode part looks like a power mod done on a 4 port board. You can still see the silkscreen for the inductor that gets removed and the soldered in Coax cable near that RCA panel mount. So my guess is that this is a 4 port board modified into a 2 port unit?

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What's the story with those replaced Caps at C30 and C32? They look to have odd lifted pads still attached to them while the legs were soldered down? Or is that some trick of the lighting? I know I've not see caps like that in my 5200 systems so this looks to be reworked for sure.

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Two port. Vs four Port. The two ports I've had all had factory mods with wires poorly soldered. Trammiel strikes again.

 

Tramiel's Atari Corp didn't mod leftover 2-port 5200s in their inventory. They AV modded the left over 4-port 5200s and also did the compatibility mod with the 2600 adapter. The 2-ports didn't need either of those mods.

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What's the story with those replaced Caps at C30 and C32? They look to have odd lifted pads still attached to them while the legs were soldered down? Or is that some trick of the lighting? I know I've not see caps like that in my 5200 systems so this looks to be reworked for sure.

 

While I've never seen any caps like this on Atari, I think what you are seeing is a light distortion. This board has had some extensive rework. The board is REV. 1

dated 7-11-83 but some of the components have a manufacture date of 9326 on them. I think I'm going to remove the wires, put the lifted pins back down, remove

the solder bridges (I found another one), fix the lifted trace, and replace the blasted resistor and see what happens. By the way, this definitely a two port board. I'll

let everyone know what happens. If you don't hear from me in awhile it's because I may have burnt the house down...

 

DavidMil

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BTW I did check 2 ports schematic and made the revision based on the mod my 2 port system has. Your 3rd picture is the same:

jEyH2JH.jpg

 

Mine also has the odd angled diode but I didn't have a lifted pin. No idea what purpose that pin served or how lifting it out of socked worked.

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BTW I did check 2 ports schematic and made the revision based on the mod my 2 port system has. Your 3rd picture is the same:

jEyH2JH.jpg

 

Mine also has the odd angled diode but I didn't have a lifted pin. No idea what purpose that pin served or how lifting it out of socked worked.

 

I fixed everything that was obvious, and the power LED now lights up but all I get on the screen is a bunch of continually wave lines.

So It's time to start looking at voltages first then wave forms on the scope. There is no telling what chips could have been damaged.

I know A26 is good because I can turn Q9 off and on with the power switch. I haven't gotten any farther yet. I'll keep you posted.

BTW, I wonder if the modifier raised pin 11 instead of cutting the trace between 11 and 12? Because the trace between the two pins

has not been cut. Nice schematic 7800fan!

 

David

Edited by DavidMil
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I fixed everything that was obvious, and the power LED now lights up but all I get on the screen is a bunch of continually wave lines.

So It's time to start looking at voltages first then wave forms on the scope. There is no telling what chips could have been damaged.

I know A26 is good because I can turn Q9 off and on with the power switch. I haven't gotten any farther yet. I'll keep you posted.

BTW, I wonder if the modifier raised pin 11 instead of cutting the trace between 11 and 12? Because the trace between the two pins

has not been cut. Nice schematic 7800fan!

 

David

 

I found a bad RAM chip. The 5200 now powers up to both Pac Man and Pole Position, but none of my four joysticks work

(including my newly rebuilt one). I'm getting there, slow but sure...

 

David

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A little more testing revels that the three old controllers are totally dead, but on the rebuilt one the Start, Pause, and Reset buttons work. But the stick doesn't do anything.

I'll swap out the Pokey chip and if that doesn't work I'm going to open up the controller again and put an ohm meter on the pots to makes sure they are working.

 

David

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