Jump to content

Photo

Having some video display issues with my used 7800


12 replies to this topic

#1 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • 406 posts

Posted Mon Mar 20, 2017 6:57 PM

I just got a used 7800 on ebay. I have it hooked up to my 21st century flat screen toshiba TV since that's the only TV I have.

I've got an RF cable going to a an RF to coax converter that I got on ebay for about $5. And that's of course plugged into my tv's antenna input. Not like it should matter to much, but the RF to coax converter advertised that it was for use with 7800s, so I'd imagine many other folks bought this item and it worked for them.

The console powers on (red LED lights up) and the display kinda does stuff but it certainly doesn't look game-like. For combat I just get a green screen that does nothing, for pitfall I get rolling brown and black bars, and for Food Fight, a 7800 game, I get a white screen. No game sounds can be heard and the display doesn't change if I press buttons on the joystick/console to start a game. 

I had heard before that the 2600 hardware inside a 7800 can break while the 7800 hardware still works, so it actually makes me feel better that my 7800 game is doing essentially the same thing in terms of not displaying correctly. 

i checked my TV's input options in the TV menus but did not see any particular settings that I could change for the coax input. 

Any ideas on what is the matter? Is it probably weak signal output by the 7800 that can't be interpreted correctly by my TV? If that's the case, I guess my options might be to have an AV mod done to the system, or buy a VCR to use as a passthrough for the AV signal...

If weak video signal does not seem to be consistent with what my symptoms are, are there any simple ways I can check whether my 7800 might be damaged in some regard?

Thanks for your help, I have a ton of games from my childhood that haven't been played in over 15 years!
 

Attached Thumbnails

  • combat.jpg
  • food fight.jpg
  • pitfal.jpg

Edited by sirlynxalot, Mon Mar 20, 2017 7:01 PM.


#2 groundtrooper ONLINE  

groundtrooper

    Chopper Commander

  • 156 posts
  • So many POKEY home brews. So few POKEY chips.

Posted Mon Mar 20, 2017 10:51 PM

I am assuming you have TV input on "Antenna"  and are tuning to channel 2 or 3. And have the console selector set on the appropriate channel. 

 

It appears you are getting some sort of signal from the 7800. But there is obviously an issue. I am sure there are others on here that can give you some more technical leads on what to try. 



#3 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • Topic Starter
  • 406 posts

Posted Tue Mar 21, 2017 6:15 AM

Yeah I tried the different channel options on the console and tv and tried coax set to cable and antenna. No dice. I'll need to bring it over to a friend's and try it on more tvs to see if the tv is at fault or the system.

#4 SmittyB OFFLINE  

SmittyB

    Star Raider

  • 63 posts

Posted Tue Mar 21, 2017 7:13 AM

From the photos I'd say it's the console and not the TV that's the issue. You're getting a clear pattern, it's just not the pattern you want. I haven't had much experience with faulty 7800s but going by the 2600 games it could just need a thorough cleaning of both the cartridges and the console.



#5 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • Topic Starter
  • 406 posts

Posted Tue Mar 21, 2017 10:28 AM

Console and carts were very dusty when I got them. I did a quick surface clean but didn't use any alcohol on the cart slot or carts yet. It's worth a try tonight.

#6 -^CrožBow^- OFFLINE  

-^CrožBow^-

    River Patroller

  • 4,498 posts
  • Collector of Fine Atari and Sega Antiquities!
  • Location:Ivory Tower, Fantasia (Oklahoma)

Posted Tue Mar 21, 2017 11:13 AM

Console and carts were very dusty when I got them. I did a quick surface clean but didn't use any alcohol on the cart slot or carts yet. It's worth a try tonight.

 

Honestly, even if i buy a game complete in the box that looks to have been kept in an airtight vault its entire life before I got it...I clean it before putting into my consoles. You would be amazed at how much black oxidation will still come off a mirror shiny contact when you throw some de-ox-it on it. 

 

So yes!...get a high concentration bottle of rubbing alcohol and q-tips and swap those edge connectors on the carts until they aren't coming out black anymore. And don't be surprised at how many q-tips a single game can take to do this...

 

To clean the cart slot is trickier, but I use an old credit card wrapped with thin cloth and soak it in alcohol or contact cleaner and then run it up and down inside the slots until again the black is gone.



#7 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • Topic Starter
  • 406 posts

Posted Tue Mar 21, 2017 5:46 PM

I gave the cartridge slot and some cartridges a very thorough cleaning. I even took apart the 7800 to get the plastic cartridge slot piece out for better access, that shielding piece is a pain in the neck to remove lol. At anyrate, the symptoms are still the same so I dunno. I'll test it with a VCR and some other tvs at friend's houses, but I might just plunk down for an AV modded 7800 and sell this one on so I can have a reliably useable system with my setup.



#8 DrVenkman OFFLINE  

DrVenkman

    Stargunner

  • 1,362 posts
  • Starmaster Leader
  • Location:KMBT

Posted Tue Mar 21, 2017 7:00 PM

My thought, if the voltage regulator tests okay and none of the capacitors are leaking or swollen, is that the TIA or 6502 are bad. Both of those are needed for both 2600 and 7800 games. If either one of them is malfunctioning, the system won't work.



#9 Stephen Moss OFFLINE  

Stephen Moss

    Dragonstomper

  • 942 posts
  • Location:Cambridge, United Kingdom

Posted Wed Mar 22, 2017 2:53 AM

My thought, if the voltage regulator tests okay and none of the capacitors are leaking or swollen, is that the TIA or 6502 are bad. Both of those are needed for both 2600 and 7800 games. If either one of them is malfunctioning, the system won't work.

 

May not be the TIA, at least not alone as MARIA handles the video for 7800 games and it is not playing them either but definitely sounds like an issue with part of the system that is common to both 2600 & 7800 games such as the 6502, system clock, TIA/MARIA selection circuits, RF unit/RF unit input or the Reset line.



#10 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • Topic Starter
  • 406 posts

Posted Wed Mar 22, 2017 6:25 AM

So it seems the issue could be one of many different things. 😅 before I plunk down for a tested and working model, how reliable are these 30 year old machines? I would have assumed they were pretty bullet proof since they don't really have moving parts but all this talk of various components breaking is spooking me. I know it'snot the 80s anymore andall the hardware is decades old. Would it be unusual that I could expect a working model to continue working for another 3 to 5 years? Are a Large number of 7800s subject to issues at this point?

#11 sirlynxalot OFFLINE  

sirlynxalot

    Moonsweeper

  • Topic Starter
  • 406 posts

Posted Wed Mar 22, 2017 6:25 AM

So it seems the issue could be one of many different things. 😅 before I plunk down for a tested and working model, how reliable are these 30 year old machines? I would have assumed they were pretty bullet proof since they don't really have moving parts but all this talk of various components breaking is spooking me. I know it'snot the 80s anymore andall the hardware is decades old. Would it be unusual that I could expect a working model to continue working for another 3 to 5 years? Are a Large number of 7800s subject to issues at this point?

#12 -^CrožBow^- OFFLINE  

-^CrožBow^-

    River Patroller

  • 4,498 posts
  • Collector of Fine Atari and Sega Antiquities!
  • Location:Ivory Tower, Fantasia (Oklahoma)

Posted Wed Mar 22, 2017 8:38 AM

So it seems the issue could be one of many different things. before I plunk down for a tested and working model, how reliable are these 30 year old machines? I would have assumed they were pretty bullet proof since they don't really have moving parts but all this talk of various components breaking is spooking me. I know it'snot the 80s anymore andall the hardware is decades old. Would it be unusual that I could expect a working model to continue working for another 3 to 5 years? Are a Large number of 7800s subject to issues at this point?

 

Well..I can tell you that anything built by man will never last forever... But you have to give credit on these old consoles. 30+ years and still kicking on most of them. There is a reason that Wall-E is playing on an atari in the movie after all. But seriously, I still have my original '88 bought 7800 and it still works just fine. I've never had to do anything with it other than when I added the Dev OS mod to it years ago. I don't actively use it now as I have another 7800 that is less nice looking and has more mods as my daily driver. But even that one has all original chips and capacitors in it minus a hex inverter I had to replace when I de-installed my LHE mod late last year. If they aren't thrown around and essentially treated decently, these things are pretty reliable. And what parts that can wear down in them that would require replacement with the exception of a few of the ICs, are readily available and should be for quite some time to come.



#13 Stephen Moss OFFLINE  

Stephen Moss

    Dragonstomper

  • 942 posts
  • Location:Cambridge, United Kingdom

Posted Thu Mar 23, 2017 2:56 AM

So it seems the issue could be one of many different things. 😅 before I plunk down for a tested and working model, how reliable are these 30 year old machines?

 

As crossbow said, if things are looked after, stored and used correctly they can operate perfectly well for decades, that said they were never designed or intended to last forever, few things ever are, I am sure Atari never envisaged people still using them 30 years down the line.

 

For example at work we are still using CD players that were manufactures & purchased around 1992, while they are becoming more of a problem to keep going even at that time the manufacture only gave them a 15 year lifespan when PCB, semiconductor design/manufacture and soldering techniques were probably greatly improved on the time when the 7800s were originally designed and built.

 

Consequently you have to expect problems with equipment the age the 7800's are, the problem could be as simple as a bad solder joint which with age and PCB flexing has now become a problem or socket creep if the IC's are socketed in which case just pushing them back in would resolve the problem.

The reason I listed several things to check is not that all those things are necessary a common cause of failure on 7800s but because there was just not enough evidence provided to specifically indicate what the exact problem was thus I was just listing things to check.  






0 user(s) are browsing this forum

0 members, 0 guests, 0 anonymous users