Color Classic VGA Woes

[JDW]

Oh, wow! And only $2.79 too... That's really amazing. Thank you for convincing Console5 to add that kit!

I'm still filming my video on the CC Analog Board parts swap. Having to deal with some lifted pads right now. Not torn-off pads, just lifted. Not too surprising in light of how hot those areas got through the years. I'm also pondering the implications that raising the parts off the PCB will have. That better cools them, but it also puts more stress on the pads.

I tried the original gray-colored JB-Weld under one pad today. Takes 24 hours to cure. I'll then see what happens when I solder the component leg to it. If it holds, I'll probably add UV solder mast atop that to further keep it down.

I originally thought about heat-shrink tubing on the legs, especially to prevent shorting, because I am lifting the new components up and off the PCB. I soldered in my DL21 diode replacement that way. And I think that's fine because that part isn't too big and heavy. But the resistors are pretty massive. I then remembered that I have some transparent silicone tubing that I bought to repair the rollers on my Macintosh Portable's trackball. Silicone is pretty heat resistant and thicker than heat-shrink tubing, so I will try to add some of that tonight after work to see if it better supports those big replacement resistors. Ceramic stand-offs would work too, but I can't find those on Amazon and prices on Mouser are pretty crazy. So my Silicone tubing idea is probably best in the end. Again, my thinking here is to prevent a heavy component that sits on its legs from pushing out the pads on the solder side of the PCB over time.

 

[JDW]

This might be a good place to mention that Luke from Console5 has graciously answered my request of turning your list of diodes/resistors into a ready to buy kit. His kits have been a life saver for folk like me who don't really have easy access to Mouser or the like. Here's the link, in case it is of use to anyone else following along:
https://console5.com/store/macintos...575-630-0349-630-0355-resistor-diode-kit.html

I have received the kit a few weeks ago but have not yet gotten around to opening up my CC again, I'm eagerly awaiting a moment when I can though.

Could you please measure resistance on the light green resistor shown in the Console5 kit below?

I only just now noticed it is 5-band, and unless my eyes are deceiving me, that means it is the wrong value...

BRN-BLK-BRN-GLD-BLU = 10.1Ω, 0.25% tolerance

The correct resistor for RL22 is 100Ω, not 10.1Ω. And it needs to be 5W. In fact, all 3 resistors really need to be 5W. They probably are, but if you find the green resistor is wrong, when you speak to Luke about it, you should re-confirm the wattage. I would also recommend he put the resistance values and the wattage values on his web page for that kit.

 

[jibsaramnim]

Could you please measure resistance on the light green resistor shown in the Console5 kit below?

View attachment 22642

I only just now noticed it is 5-band, and unless my eyes are deceiving me, that means it is the wrong value...

BRN-BLK-BRN-GLD-BLU = 10.1Ω, 0.25% tolerance

The correct resistor for RL22 is 100Ω, not 10.1Ω. And it needs to be 5W. In fact, all 3 resistors really need to be 5W. They probably are, but if you find the green resistor is wrong, when you speak to Luke about it, you should re-confirm the wattage. I would also recommend he put the resistance values and the wattage values on his web page for that kit.

Apologies for the belated response. I was able to measure the resistance of the resistor yesterday, and can happily report that it does measure correctly at ~100Ω. I was working on the analog board of my CC I too was scratching my head, as as I couldn't make sense of its value based on its color bands. I even asked my wife if I was perhaps seeing the wrong colors, but she confirmed seeing the same colors.

I do agree it would be helpful for Luke to add a bit more description to the listing, and update their wiki page to list these too. I was referencing your (very helpful, thank you!) images/gifs when working on my board, as I like to have a visual companion when doing these types of things.

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I can also happily report that my second Color Classic seems to be working very nicely so far after recapping its analog board and replacing these resistors and diodes with Console5's kit(s). I must admit that the included 1N5344B diode has legs that feel way too thick, so it's not actually possible to install it without increasing the hole sizes a bit. That's a bit of a scary undertaking especially as these components that run super hot already seem to increase the odds of lifted/loose pads.

Still, the CC has been running like a champ for 3-4 hours yesterday and about the same today so far, which I'm very happy about.

 

[JDW]

@jibsaramnim
I'm both pleased and shocked that resistor measures 100Ω. Great you don't need a replacement, but that Blue or Violet 5th band at the end is unusual. It's not unheard of for high precision resistors like 0.1% tolerance ones, but those are expensive and your kit was cheap, so it can't be that. Again, this is why having more detail specs on each part is helpful. Anyone with a good eye for resistor color bands may be misled into thinking that 100Ω resistor is only 10Ω. But again, thanks for confirming it's correct.

It was interesting to hear you couldn't get that one diode installed through the holes in the PCB. Does that mean you drilled them out?

Thick wires are actually a good thing because the heat will flow from the super hot body into the legs and eventually into the pad and copper PCB traces too. All will dissipate that heat on some level. The thinner the legs, the less surface area and less heat dissipation they would offer. Current flow is another benefit of having thicker legs. But obviously, if they are too thick, you have problems with some PCB pads (holes too narrow).

 

[jibsaramnim]

I'm both pleased and shocked that resistor measures 100Ω. Great you don't need a replacement, but that Blue or Violet 5th band at the end is unusual. It's not unheard of for high precision resistors like 0.1% tolerance ones, but those are expensive and your kit was cheap, so it can't be that. Again, this is why having more detail specs on each part is helpful. Anyone with a good eye for resistor color bands may be misled into thinking that 100Ω resistor is only 10Ω. But again, thanks for confirming it's correct.

Same here, I'm glad it measured correctly. I've reached out to Luke to ask about this (and to ask if he's able to put detailed specs in his product listing as-well as update the Console5 wiki), I'll follow up with any updates I might get pertaining this!

It was interesting to hear you couldn't get that one diode installed through the holes in the PCB. Does that mean you drilled them out?

Indeed I did yes. I understand that thicker wires (or, legs) can be helpful, but as they were they just couldn't fit through the board. Some hole expansion did the trick though, but I do feel like this helps push the whole process of replacing these diodes to a slightly higher difficulty level. Not impossible though, as even amateur-hour I was able to get it done I suppose .

 

[JDW]

... the whole process of replacing these diodes to a slightly higher difficulty level.

We should perhaps say, "with the Console5 diode." Because the parts I purchased from Mouser did not require any drilling, and the legs on that particular diode were pretty meaty too. I guess yours was just meatier still.

I agree though that drilling isn't something most people would want to do, especially when most people probably wouldn't even have the right sized drill bit. On top of that, you run the risk of loosening the pad from the solder side of the board. Glad to hear that didn't happen to you though. I lifted some pads simply by using my FR-301 desoldering gun while removing the stock components! All that heat through the years makes some pads quite weak and there's little that keeps them clinging to the board other than the green UV solder mask on them.

 

[jibsaramnim]

We should perhaps say, "with the Console5 diode."

Yes, that indeed was my intended meaning, quite good to have that be made extra clear, thank you!