5200 Issues - Technical Orientated

[SamhainTM]

So, I finally decided to dive into fixing one of the 5200s I have. It's a 4-port model from early 1983. Applied the power mod, ripped out the RF modulator, and added a UAV+IAB "sound card". I also replaced both 7805s with R-78 switching regulators and replaced the MJE210s. 4050 & 4013 have also been replaced. Scanned over the entire board looking for cold or cracked joints and didn't notice anything out of the ordinary.

 

System powers up, LED is on, but no video or sound. Just a black screen and an audio pop when powering off. The 1W resistors at R57 and R58 also get really hot. I do not have replacement resistors on hand at the moment, but will order some soon.

 

Ran through the service manual troubleshooting flowchart, which basically recommended replacing the MJE210s and R57/R58 resistors. 

 

Has any one else run into this problem before? I'm concerned that replacing the resistors won't fix the issue. I have another, earlier model 5200 from late 1982, so I should have the correct ICs if I need to start swapping them. 

 

Thanks in advance for any help.

[+-^CrossBow^-]

Why did you remove the RF modulator? and what is the IAB? Is that the add in audio board that TBA sells mainly for the 400?

 

I've done nearly the same as you have specified with mine only I've a pair of Traco 2450s in mine. Don't believe I've had to change out the MJEs at all thoug.

 

[SamhainTM]

7 minutes ago, -^CrossBow^- said:

Why did you remove the RF modulator? and what is the IAB? Is that the add in audio board that TBA sells mainly for the 400?

 

I've done nearly the same as you have specified with mine only I've a pair of Traco 2450s in mine. Don't believe I've had to change out the MJEs at all thoug.

 

Pulled the RF because I will never use it and don't want the interference from it (don't worry.. it was safely removed and placed into storage). Yes, the IAB is from TBA and it's supposed to be rated for the 5200. Real simple hook up on it: Audio in, Audio out, 5v in, Ground. Seems to be working as I do hear a audible pop when powering off.

 

I have a metric ton of MJEs as I had to buy a large bag to get one for my 7800 last year. Service manual recommends replacing them in one of the flow paths, along with the 1W resistors.

 

I've been tracing voltages since last night and the ICs all seem to get the proper voltages. Ordered the R57/R58 1W resistors and should have them by Monday. Still no luck on anything with this beast. I even threatened it with a firearm, which usually works on the most stubborn of servers, but not on this little (large) black box.

[SamhainTM]

Oh, and the R-78s work like a charm. Updated my Sega master system and will definitely use them on my NES rebuild. Expensive, but worth it for long term replacements.

[+-^CrossBow^-]

Honestly I've never seen any interference from the RF with the UAV. I like that since the RF is a good way for me to quickly test if there is an issue with the console or the UAV work in case of something like this. What game were you using when you were testing?

 

And you said you replaced the 4050? Is the UAV attached on top it then I assume?

 

[SamhainTM]

I have no way to use RF at this point in time, so that's the main reason. Schematics show that it shouldn't cause any issues being removed, but I may be wrong.

 

I was using Pole Position, Space Dungeon, and Vanguard. to test. May try a few older games later though.

 

4050 is mounted on top of the UAV with the jumpers simply soldered in place (correctly... I triple-checked).

[+-^CrossBow^-]

15 hours ago, SamhainTM said:

I have no way to use RF at this point in time, so that's the main reason. Schematics show that it shouldn't cause any issues being removed, but I may be wrong.

 

I was using Pole Position, Space Dungeon, and Vanguard. to test. May try a few older games later though.

 

4050 is mounted on top of the UAV with the jumpers simply soldered in place (correctly... I triple-checked).

Okay, sounds like how I was doing 5200 UAV installs originally. I now just solder the socket to the top of the 4050, solder in leads for the jumpers on the UAV and then pop the UAV into the socket as it takes me much less time that way. However, to keep things low profile I will remove the socket that the 4050 was in, and solder the 4050 directly to the mainboard. Again, to lower the profile as much as I can so the top RF can still be reinstalled. It was working prior I assume? Because if you have power going everywhere that it should, then I would start to blame the RAM chips on the left side of the board. You could start by swapping from the bottom and top to see if you can get anything to come up or change.

 

[SamhainTM]

1 minute ago, -^CrossBow^- said:

Okay, sounds like how I was doing 5200 UAV installs originally. I know just solder the solder to the top of the 4050, solder in leads for the jumpers on the UAV and then pop the UAV into the socket as it takes me much less time that way. However, to keep things low profile I will remove the socket that the 4050 was in, and solder the 4050 directly to the mainboard. Again, to lower the profile as much as I can so the top RF can still be reinstalled. It was working prior I assume? Because if you have power going everywhere that it should, then I would start to blame the RAM chips on the left side of the board. You could start by swapping from the bottom and top to see if you can anything to come up or change.

 

Yep. I basically followed your videos to get an idea of what I needed to do. Only difference right now is that the 4050 socket is still in place (see pics below).

 

I just swapped the main ICs (U2, U3, U5, U7, and U8 so far). Getting ready to swap SRAM chips shortly.

 

 

[+-^CrossBow^-]

that audio board looks way more complicated than what is needed. I just wire up a 2K resistor and 10µf cap inline off of R50 and it sounds great! I actually have one of @Bryans older UAC boards but haven't installed it into anything. Just haven't really needed to so far.

 

[SamhainTM]

3 minutes ago, -^CrossBow^- said:

that audio board looks way more complicated than what is needed. I just wire up a 2K resistor and 10µf cap inline off of R50 and it sounds great! I actually have one of @Bryans older UAC boards but haven't installed it into anything. Just haven't really needed to so far.

 

I had a few IABs lying around, so I used them. I've got some 10uF caps on the way though since I seem to have everything else but that value.

 

Thanks for all the info. I'm really close to taking this thing down to the gun range and teach it some lessons... but I won't . Serves me right for letting them sit in a box for the past 25 years with no love or attention. 

[+-^CrossBow^-]

20 minutes ago, SamhainTM said:

I had a few IABs lying around, so I used them. I've got some 10uF caps on the way though since I seem to have everything else but that value.

 

Thanks for all the info. I'm really close to taking this thing down to the gun range and teach it some lessons... but I won't . Serves me right for letting them sit in a box for the past 25 years with no love or attention. 

Well, I do have a few 5200 main boards that I've never been able to figure out what the heck was wrong with them. They have been great for donor parts boards! Odd thing is that my first 5200 that worked great for years just suddenly up and started acting goofy one day. I turned it into the first parts donor. Now...about 80% of its parts have been stripped and used for other things and I still haven't found what part was the issue LOL!!!

 

[SamhainTM]

That's my current plan right now also. I've got 3 4-port units and I figure I can make at least one good one out of the batch.

[SamhainTM]

Well... this happened: 

[SamhainTM]

Swapped the motherboard around with a different one and it came right up.

 

Controllers don't work at the moment though, but that's a tomorrow job.