Colecovision RF issues - I need some assistance

[birdie3]

I posted this here because this forum has many readers and I figure someone will know how to repair this..

 

I just picked up a new (used) CV last night and there seems to be an issue with what I assume is the RF output. The console works but the audio is quite static and the video is looking like it needs to be tuned. The picture is there but it's looking like a TV channel does when it's not tuned in properly. This also happens on both channel 3 and 4. Does anyone know what is going on and how to repair this? It seems simple enough but I have never dealt with this type of problem on a Colecovision before. This also happens to be a later American version of the console if that helps anyone.

[joeybastard]

Are you using a TV/Game switch or straight in with an RF adapter? The CV RF cable is detachable so for an easy test, I'd try switching out the cable first and if you're using the TV/Game switch, get an RF adapter instead.

 

MY CV is hooked up using the RF adapter and the picture is excellent. On a few games I do get some slightly distorted audio but it's intermittant.

 

AA member DoubleDown sells some beautifully restored CVs with the modification for RCA hookups, you should check out his website about these.

[doubledown]

Are you using a TV/Game switch or straight in with an RF adapter?  The CV RF cable is detachable so for an easy test, I'd try switching out the cable first and if you're using the TV/Game switch, get an RF adapter instead.

 

MY CV is hooked up using the RF adapter and the picture is excellent.  On a few games I do get some slightly distorted audio but it's intermittant. 

 

AA member DoubleDown sells some beautifully restored CVs with the modification for RCA hookups, you should check out his website about these.

841156[/snapback]

 

He's right I am a bad-ass. If you're using a TV/Game switch, lose it and try a direct connect phono-to-Coax adapter. If it's still problematic, it probaly needs a good cleaning. The power switch and cartridge slot, I'm sure, are very dirty.

[birdie3]

Are you using a TV/Game switch or straight in with an RF adapter?  The CV RF cable is detachable so for an easy test, I'd try switching out the cable first and if you're using the TV/Game switch, get an RF adapter instead.

 

MY CV is hooked up using the RF adapter and the picture is excellent.  On a few games I do get some slightly distorted audio but it's intermittant. 

 

AA member DoubleDown sells some beautifully restored CVs with the modification for RCA hookups, you should check out his website about these.

841156[/snapback]

 

He's right I am a bad-ass. If you're using a TV/Game switch, lose it and try a direct connect phono-to-Coax adapter. If it's still problematic, it probaly needs a good cleaning. The power switch and cartridge slot, I'm sure, are very dirty.

841179[/snapback]

 

I am using a Radio Shack gold RCA to Coax connector. Those switch things suck man. I sprayed the power switch last night w/ tuner spray and it still doesn't work right. It's not the cart slot either. Maybe I just need to clean it more..

[Seob]

It's not a PAL console maybe?

It also could be that you're tv-set tuner has trouble tuning in on channel 3 or 4.

I've found out at a friend that his new tv-set hat trouble with getting clear picture on channel 3 and 4. When he tryed his set on a older tv instat the picture was clear. Because he had more trouble with this tv (a JVC) he trade it in for a Philips tv. This tv had a hi-end tuner and with this set he didn't have any trouble getting a good picture.

[birdie3]

I am starting to wonder if it is a PAL model. I have 3 other CV's and they all work fine on channel 3 and 4. It rolls on channel 3 sometimes and this is how PAL consoles generally appear on my set. Is there a good way to tell if it is a PAL console?

[JB]

I am starting to wonder if it is a PAL model. I have 3 other CV's and they all work fine on channel 3 and 4. It rolls on channel 3 sometimes and this is how PAL consoles generally appear on my set. Is there a good way to tell if it is a PAL console?

841220[/snapback]

Hook it to a PAL TV and see if it behaves?

</not-very-helpful>

Edited April 21, 2005 by JB

[Seob]

I own a pal version but i check everywhere but can't tell from the outside if it's a pal or ntsc one. There simpley aren't any pal markings what so ever.

But on this site i found something that maybe usefull for you.

colecovision faq

 

13.1) To fix a rolling picture/video problems:

 

The problem is with the power switch. You'll notice that if you were to jiggle it a little without turning the system off that it will make a complete mess of your screen. What I suggest is that you desolder the power switch from the circuit board, take the metal cover off of it and clean all the contacts and re-grease them after cleaning them. Make sure the metal cover is REALLY TIGHT when you put it back on though. From then on if you are very careful when turning the unit on/off it should work OK for you.

 

If you still have a problem go to an electronics store... and get a similar switch and replace it. Nothing else you can do really. - 05

 

Sorry if this is stating the obvious, but you seem to have a combination of an intermittent open and a heat sensitive component.

 

Get a can of "cold spray" made for isolating thermal intermittents: should be a couple of bucks at a local electronics shop. If you can get the box open and get to all the components, it should be fairly straightforward to figure out which one is the bad guy.

 

Actually, by your description (starts good, goes bad after 2 minutes, can be affected mechanically) leans towards a bad solder connection (or socket it the darn thing has them). It may be as easy as touching up a few solder connections. - 06

 

If the video problem is simply vertical lines dragging behind the sprites, it can sometimes be solved by using a different power supply. - 16

 

A number of problems (warping sprites, lack of audio, lines in sprites, etc.) can, in many circumstances, be solved simply by assuring a solid connection between the power supply and unit. This can require hardwiring the power supply to the unit. - 33

 

In some cases, sprite problems can be solved by cleaning the cartridge in question. But if the startup screen has letters screwed up, such as CKHACK, you probably have a bad DRAM. U10 is D7 and U17 is D0. CKHACK indicates a bad D2 line, which would be U15. General directions for replacing a bad chip can be found in Section 10.3. - 29

[birdie3]

I would lean more toward the notion that this is a PAL console. I have sprayed the power switch and nothing happens. How does your video display look on your PAL console, Seob?

[doubledown]

I would lean more toward the notion that this is a PAL console. I have sprayed the power switch and nothing happens. How does your video display look on your PAL console, Seob?

841291[/snapback]

 

Did you completely disassemble the switch or just spray it from the outside. If you just sprayed it, I don't think that that would have done you much good. Those switches were originally assembled with a di-electric grease to help connectivity. The only problem with that is that they are also a magnet for dust and dirt. When I refurbish a console, I disassemble the switch, burnish and de-oxidize and condition all the contacts. And do not re-pack with grease. If you use a contact conditioner you don't need to. Plus you will have less future problems with the switch.

[birdie3]

Problem solved. It's not PAL. It's not the TV tuner. It's not the power switch. I located the trim pot in the RF box and tuned it. Now it works perfectly. Cool!!

 

Just to add to this, I have never had to open the housing on the power switch to get it sprayed properly. I just use the straw that comes with the spray and spray it into the ends, switch it back a forth a few times, then... it's as good as new.

 

I am surprized nobody knew about the RF trim pot.

[Seob]

@birdie3

 

When turned on with no game it will say:

colecovision tm

turn game off

before inserting cartridge

or expansion module

c 1982 coleco

 

c stands for the copyride logo.

Nothing else. Only the gamecartridges i have, have a label on it saying that it is a pal version. The other link is my powersupply that rates 220v.

But since the coleco has a detachable powerbase it is hard to tell what kind of console it is. Maybe the only link would be a mark inside the coleco on the motherboard that indicates what version the console is. Most likey somewhere near the rf-tuner.

 

Glad you fixed the problem. Since i never opent my coleco before i wasen't awere of the trimpot.

Edited April 21, 2005 by Seob