Bad VRAM

[Paranoid]

I've got a Colecovision that has been modded with Red/White/Yellow RCA video out. It worked great before my trip across country, but once I unpacked it and set it up here in Ohio, it has never worked right. Sometimes, some games will be playable with graphic glitches, but most games do not work at all.

 

I loaded up my AtariMax Coleco 128-in-1 cart and ran the RAM and VRAM tests, and I'm getting a VRAM error. I can provide the code if that helps.

 

The weird thing is, if I mess with how the cartridge is inserted in the slow, it seems to have an effect on how corrupt the graphics appear.

 

Is this something that can be fixed, or is it time to start looking for a new Colecovision system on eBay? I really like the RCA out on this unit (it also has been modded to have a 9 PIN male on the side, so you can hook up a regular Atari joystick).

 

Anybody got any suggestions? Bums me out that the Coleco is the one unit that didn't survive the trip across country.

[cOLeCoHiTMan]

At the very worst send a message to Yurkie and see if he thinks its fixable. You might have worse luck getting one off ebay!

[Ikrananka]

Sounds like a classic case of power switch deterioration. If this is the case then it is a fairly simple fix. Check out the following:

 

http://www.atariage....ost__p__2019087

 

If you don't want to do this yourself then this is a service that Yurkie provides.

Edited December 23, 2011 by Ikrananka

[Paranoid]

Hey... I dug through my stuff and realized I had another Colecovision... without an RCA mod and joystick mod. Same power brick (only have 1). So, I hooked it up, powered it on, ran the VRAM test - and it failed in the same way - same memory address. So I tried my carts... and SOME of my carts worked FINE on this second Colecovision (but the reason I got the Coleco with RCA out was because the 1st one was having problems)...

 

So... my question is... could it be the CARTS that are bad? And... is the VRAM test a Video Ram test of the Coleco or the hardware? I guess I need to talk to the AtariMax guy. I've been out of this scene for awhile... is his name Chuck, or Charles? It isn't MAX... is it?!?

 

I dunno. My Nephew is coming back from Malaysia to spend a few days with me over New Years - and I just wanna let him relive Gateway to Apshi. It may not happen. I might have to do it in emulation...

[ColecoDan]

When the colecovision is going bad some games work and some games don't based on how graphically superior one is over another. A lot of time when graphics start going bad it is the on off switch that needs a good cleaning and re-greasing. To me it is also not the end of the world to find a new $12 - $16 power brick to test that out as well but I don't know your financies maybe that is a lot to spend just to test out.

 

Yurkie can definately make your systems like new if you can afford it. I don't think you are too far from him either distance wise.

[cOLeCoHiTMan]

AtariMax is Steve...

[NIAD]

Not too long ago, AA member "rmaerz" had the same problem with his ColecoVision... some games worked while others showed varying degrees of graphical corruption. I think if I recall correctly that the culprit ended up being the Power Supply Transformer and/or worn Power Connector on the back of the console, which makes sense in your case because you said you had to use the same one for both systems. If he "rmaerz" doesn't chime in, you might want to search for the thread he started.

Edited December 24, 2011 by NIAD

[Paranoid]

Thanks for the feedback. I'll look into the powerbrick and the power switch - and if those don't work out, I think either way I'll be engaging Yurkie's services. He sounds like the go-to-guy for Coleco issues.

 

Thanks again, everyone!

[ColecoEric]

Just today I experienced this very problem myself.

 

I also have the CV from when I was a kid which works very well still, I only use that one.

 

I have several Coleco's that work 'almost' good (a German, UK and French one) often getting distorted images, sprites that are not always right.

Incidently I use the powersupply of one of these systems instead of the one I have in the box.

 

Anyway, recently I got a modded Coleco from Yurkie and it contains a pause-switch which I use fairly often (its a great addition for when nature calls lol!).

 

Today I experienced the same corruption when I started the CV. When I received the unit a few days ago it worked perfectly.

At first I thought it was caused by the Atarimax flashcart which I got but sadly the same thing happened when I inserted the original cartridges. And its selftest rom gave a clue 'VRAM Fail'.

 

I must remember next time to do a search on this forum because thats how I got in this thread .

After reading possible causes like a powersupply going bad, I got the old one from my box... and... the problem is gone.

 

How silly of me to depend on a probably much used and worn out powerblock, instead of using the one I had in mint condition in my ColecoVision boxed set.

 

Thanks NIAD (and others) for pointing me in the right direction.

[SlowCoder]

Man ...

Funny that I found another old CV last weekend, and my Yurkie CV got all jealous and started acting up in exactly the same fashion! Sporadically corrupt sprites and text. I also ran the VRAM test on my AtariMax cart and had the same failure everyone else seems to be getting. I ran the test a few times, and played some Pepper 2 in between. After a while, my VRAM tests started to pass, and games are looking more normal. I'm assuming this is due to warming up. I'll play with it some more to determine if it's the console or the power brick.

 

Other than just swapping out, what's the best way to test the brick? Is there an output voltage chart somewhere?

 

I would also like to ask this ... (it's a sensitive question, so please don't take it as blame on anyone's part. It's only an inquiry due to the seeming pattern in this thread.) Is it possible that something in the modded systems could be a factor, like the RCA video mod pulling too much amperage?

[Yurkie]

Man ...

Funny that I found another old CV last weekend, and my Yurkie CV got all jealous and started acting up in exactly the same fashion! Sporadically corrupt sprites and text. I also ran the VRAM test on my AtariMax cart and had the same failure everyone else seems to be getting. I ran the test a few times, and played some Pepper 2 in between. After a while, my VRAM tests started to pass, and games are looking more normal. I'm assuming this is due to warming up. I'll play with it some more to determine if it's the console or the power brick.

 

Other than just swapping out, what's the best way to test the brick? Is there an output voltage chart somewhere?

 

I would also like to ask this ... (it's a sensitive question, so please don't take it as blame on anyone's part. It's only an inquiry due to the seeming pattern in this thread.) Is it possible that something in the modded systems could be a factor, like the RCA video mod pulling too much amperage?

 

If you need help send me a PM.

 

with power plug facing you. Looks a little like a smile. left most hole is up and then 2 down and then right most hole is up. Put Negative lead in upper left hole and leave it there insert posite probe into holes 2, 3 and 4 2nd hole is 12V hole 3 is -5V and hole 4 is +5V

[SlowCoder]

Man ...

Funny that I found another old CV last weekend, and my Yurkie CV got all jealous and started acting up in exactly the same fashion! Sporadically corrupt sprites and text. I also ran the VRAM test on my AtariMax cart and had the same failure everyone else seems to be getting. I ran the test a few times, and played some Pepper 2 in between. After a while, my VRAM tests started to pass, and games are looking more normal. I'm assuming this is due to warming up. I'll play with it some more to determine if it's the console or the power brick.

 

Other than just swapping out, what's the best way to test the brick? Is there an output voltage chart somewhere?

 

I would also like to ask this ... (it's a sensitive question, so please don't take it as blame on anyone's part. It's only an inquiry due to the seeming pattern in this thread.) Is it possible that something in the modded systems could be a factor, like the RCA video mod pulling too much amperage?

 

If you need help send me a PM.

 

with power plug facing you. Looks a little like a smile. left most hole is up and then 2 down and then right most hole is up. Put Negative lead in upper left hole and leave it there insert posite probe into holes 2, 3 and 4 2nd hole is 12V hole 3 is -5V and hole 4 is +5V

Thanks Yurkie. I'll try to check it this weekend. I turned it on this morning, and couldn't get it to error this time, so it may not be a warmup issue.

[SlowCoder]

After 10 days of almost 30 minutes of play each day, the CV hasn't acted up even once. It had been a couple months since I'd cranked it up before that, so maybe there's a cap that's about to go.