7800 color problem

[KHORTON]

Just picked up a 7800 system from Ebay. It had all the original components except the RF switchbox and cable. I'm using the RF switch from my 2600 system and a standard composite video (RCA) cable.

 

The image is razor sharp, except I'm only getting black and white -- no color. Would your guess be that this is a problem with the system or do you think it would be corrected with a different cable or RF box?

 

Any ideas are appreciated...thanks...

[Video]

I use the same old style game switch box for all my old systems. My 7800 runs in full color just like my 2600.

 

My immidiate guess would be that the system thinks the Pause button is being pushed, which is the same as the BW switch on the old 2600. But that would only affect 2600 games and keep 7800 games that use it paused permanantely. But give it a push anyways, it should click like the other buttons.

 

Other than that, I have no Ideas.

[KHORTON]

The pause button seems to be fine and did not cure the problem. Thanks for the suggestion though.

 

Is there any reason a standard video cable would be the issue here? I can't use the signal cable from my 2600 because it is hardwired into the 2600 unit, where the 7800 has the jack to connect the cable to.

 

 

...Kevin

[DamienC]

This (sort of) happened with my 7800 a while back (I was getting no colors except for yellow).

 

I posted about it here and was told that there are two pots on the 7800 board which allow you to adjust color. Open up the 7800 and remove the RF shield and there should be two circluar black things below the cartridge port that you can rotate and adjust for the best color. If I'm not mistaken, the one on top is for 7800 games and the one on the bottom is for 2600.

[+Mitch]

Are both 2600 and 7800 games on that 7800 in black and white?

 

Mitch

[Video]

You would use a RCA cable to connect your 7800 to a switchbox. It doesn't work with something like the NES switchbox (I don't know why, wrong signal or something?)

 

That's a good point. What games aer you playing in this system? Most carts have either 2600 or 7800 in fair sized letters on them.

[KHORTON]

I get only black and white regardless of game type - 2600 or 7800.

 

When I get some time, I will disassemble and check for the color adjustment mentioned.

 

Based on the feedback, I will assume the cable and the RF box is not the issue here, since the box works fine with the 2600 unit.

 

In the meantime, if anyone has other ideas, would love to hear them.

 

Thanks all.

 

...Kevin

[+-^CrossBow^-]

okay...what about the RF tuner itself? I suspect that the RF circuit itself needs to be adjusted especially since your getting BW on all games regardless of type. On the upper left hand part of the main board just to the left of the cart connector is the RF circuit area. You should see either a red post coil on the outside of the RF box..or perhaps it is on the insise of the RF shielded box. Either way, there will be a coil you can adjust. Basically you take an Allan wrench and fit it into the coil. Then you slowly turn clockwise or counterclock wise until you get both your Color and Sound. Yes, out of ajustment can also cause sound to be staticy or non existent in addition to a lack of color.

 

That is my only thought espcially since your 2600 seems to work okay with your current switchbox. Also, might check the TV signal switch. The 7800 has one on the back side next to the RF. I just has a circle and triangle instead of 2 or 3...which I always thought was strange. Could be it will work better on one channel than the other. I had a Colecovision that was like this once. Gave me BW only on Channel 3 but looked great on channel 4. Turned out it needed the RF adjusted...hehe

 

[telford777]

On 4/20/2003 at 5:27 AM, KHORTON said:

Just picked up a 7800 system from Ebay. It had all the original components except the RF switchbox and cable. I'm using the RF switch from my 2600 system and a standard composite video (RCA) cable.

 

The image is razor sharp, except I'm only getting black and white -- no color. Would your guess be that this is a problem with the system or do you think it would be corrected with a different cable or RF box?

 

Any ideas are appreciated...thanks...

 

[telford777]

Gently turn the screw I have highlighted.

[John Stamos Mullet]

33 minutes ago, telford777 said:

Gently turn the screw I have highlighted.

LOL.

 

The thread is 17 years old.

 

Pretty sure he doesn't need our help at this point.

[+-^CrossBow^-]

45 minutes ago, telford777 said:

Gently turn the screw I have highlighted.

First of all, you have posted a pic for a PAL console which may or may not have been applicable.

 

2nd... you resurrected a thread from over 17 years ago?!