Resister repair before A/V mod ( IntelliVision )

Resistor repair before A/V mod ( IntelliVision )

Hey everyone!


I'm playing my IntelliVision on my new LED and now the screen jumps up and down about an inch or so for every game. It didn't do it for about 35 minutes yesterday while playing Burger Time. I opened it up today and this is what I saw (see attached).

Is it possible that this resister can be causing that? I thought the RF modulator would completely control the images to the screen. Another weird thing is that if I pull the RF wire out completely and put it partially back in the end of the IntelliVision slowly where it is staticy and noisy, the screen stays still. As soon as I push it all the way in, the screen displays amazing colour and quality but the screen starts to jump up and down.

I don't have a CRT television to test on


tokenring

 

This "resister" sure looks like it sustained some heat.

 

It's hard to tell from the pictures too, but the metal under the coloured coating seems to also have a laceration in it too. I wish I could find out if this would cause my symptoms?

 

Its possibly related.
From what I have encountered before, a resistor does not burn by itself. It usually burns because something else failed. So It is possible that if you replace it it will just burn again.

 

I hear ya, but leaving it there doesn't solve anything either, no?? I need to replace it either way and see if there is in face another problem.

 

Also, interestingly... it works like a charm other than the screen jumping up and down like I mentioned. You would think I would get the occasional freeze and glitch, but it doesn't.

 

True enough, If problem persists, Check for some burnt transistor.

I am not familiar with the Intellivision. What part of the circuit do you think this resistor is related to? Looks like Power supply area from the pics.

 

I'm not sure what/which part of the IntelliVision it is. I'll get the schematics and take a picture of the entire inside and identify the area. I'm looking around all the forums and threads for someone who would know. I don't want to get rid of this unit. ;-)

 

It's a 12 ohm resistor rated for 2 watts. Judging from the official schematics, it's connected to that 2-pin connector you see on the power supply board.

 

(working from memory) - there are 3 sections to the Intellivision, the main motherboard, a daughterboard for the video stuff, and the PSU; the photo you have is the PSU which generates a variety of voltages from AC mains - +12v, +16v, +5v, -3v. The Intellivision needs regulated voltage so any fluctuations might cause issues, and the resistor you indicate which has clearly got damaged, needs replacing. It is probable that the damaged resistor is causing the fluctuations you experience; it needs changing anyway.

 

You guys are so great! I really appreciate you all helping out. I'm doing my pictures now just to make sure. Before I had opened it up and noticed it, I ordered to more RF modulators for the unit. I guess it's good to have those anyway. I'll keep everyone posted.

Aaron

 

Okay, I grabbed a 5 pack of resistors @ $0.39 each. They look way smaller than the one that is in there. I hope they are fine. I'm pretty much going to go for it now but I'm going to watch and see if anyone replies to this. Let me know if I'm doing anything wrong or missing anything.

1) discharge power in IntelliVision (leave on, unplugged for ~ 10 min)
2) work in area with little or no static possibilities (the best I have is cardboard, no long sleeves, no carpet area)
3) *** not sure which is the best way to ground myself (IntelliVision doesn't have a ground and I don't have a strap)
4) remove circuit board that broken resistor is on
5) remove resistor (broken)
6) replace with new
7) put back together
8) test

Does this sound reasonable?

 

Here is a link to the video I recorded of the screen. The quality actually is a lit better than it looks in the video (just a bit blurry)

[video]http://s300.photobucket.com/user/marley3333/media/Fun/VIDEO0002.mp4.html[/video]

 

I switched the resistor. The same issue is there. I've used this RF cable, 2x Nintendo RF cables, 1x Turbo Grafix cable and they all behave the same. When I was clipping off the wires after soldering them, I almost pulled one of the traces back. If you do, and instead of running a wire to where the trace was going, can you use adhesive to hold it back down to the board?

I'm just asking just in case in the future.

Aaron

 

Those are not the correct wattage resistors. Look like possibly 1/4w.

 

Really? It said 12 Ohm / 2 Watt on the package or the row I got them from. What would that change (wrong wattage).

 

Hard to judge the size in the pic. Figured they may not be right cause of the large size difference.
It would overheat if the wrong wattage. Probably worse than the original.

you sure it did not say 1/2 watt? Found an image on this page:
http://www.mikroe.com/old/books/keu/01.htm
Says length on 1/4w should be 6.3mm, 1/2w 9.2mm, and 2w 14mm.

 

Well that sucks. Looks like I need to go see them again today. I'll grab the right one this time. Thanks for noticing Mickcris.

 

I just called the store. Those were 1/4 watt. I can't believe that. Okay, I'm back out to do it again. Just to be clear when you said it was worse that I had the 1/4 watt instead of my broken one, did you mean worse as in "it might cause more damage to the system" or "make the video worse"? I'm thinking damage because of burning out the low wattage resistor and causing damage?

I wonder if it is the RF modulator too? I don't want to AV mod it yet. I have 2 RF modulators coming in the mail also. I wonder if those are easy to change. First, let's get a VCR with SCART (what is SCART)

Aaron

 

the resisitor just might burn up like the last one. probably more so as its rated at less wattage. it could cause damage.