color classic will not boot

[mraroid]

I tried a PRAM reset while I tried to boot my dead CC. I held down the Command, Option, P & R key while I pressed the power on key on the keyboard.  The CC made one happy chime.  That was it. 
 
I can remove the power, rer seat the motherboard, and do it all over again, and it will make one chime, but that is it.
 
Nothing on the screen and no other sound.  I checked the voltage of the battery on the motherboard.  It is fine (the battery is new).
 
If this CC has a CUDA switch, I can't find it.
 
Suggestions welcome.
 
jack

 

[bibilit]

No Cuda switch...

The only solution will be to have another CC and swap boards.

 

[mraroid]

Thank you bibilit...  I will play with it a littl more.  If no joy, maybe I can buy a good working motherboard.  I just had this one re caped.  So I hope I can get it to work.....

jack

 

[Bunsen]

Is there a fresh battery in it?

 

[uniserver]

it sounds to me like a rom issue.

maybe the rom's went bad...  not something that is common ... but i have seen it a time before, with the color classic infact.

the way its acting.... is the same way it would be acting if the rom's were not installed at all.

 

[Macdrone]

trace could have just gave out also or a pin bend on where the board slides in is actually pretty common.  The cables to the A/B board are they all hooked up?  I find there are 2 connections that get hung up and pulled when moving the machine around while putting the analog board back in.

 

[Elfen]

I'm hoping it's not this. Does the CRT lights up at the back? Got a hammer or a metal wrench? Lightly tap the CRT with the tool. If it makes a "Tink!" noise then it should be intact. If it makes a "Tunk!" "Thunk!" or other deep tone noise then the CRT may have cracked and died. I'm hoping its something else that is simple and not the CRT. CRT's do crack due to sudden temperature changes or a drop, and the crack is so small that it is not seen.

 

[mraroid]

Is there a fresh battery in it?

Yes, fresh battery.  Checked it with my VOM and it is looking great.

 

[mraroid]

trace could have just gave out also or a pin bend on where the board slides in is actually pretty common.  The cables to the A/B board are they all hooked up?  I find there are 2 connections that get hung up and pulled when moving the machine around while putting the analog board back in.

Yes, the cables are hooked up.  But I will look at the A/B under a magnifying glass.  Good tip.  Thanks.

 

[mraroid]

it sounds to me like a rom issue.

maybe the rom's went bad...  not something that is common ... but i have seen it a time before, with the color classic infact.

the way its acting.... is the same way it would be acting if the rom's were not installed at all.

Humm.  Buying and shipping two ROMs to Ecuador is cheaper then buying another analog board I guess.  I will try to rule out anything else first.  Thanks

 

[mraroid]

I'm hoping it's not this. Does the CRT lights up at the back? Got a hammer or a metal wrench? Lightly tap the CRT with the tool. If it makes a "Tink!" noise then it should be intact. If it makes a "Tunk!" "Thunk!" or other deep tone noise then the CRT may have cracked and died. I'm hoping its something else that is simple and not the CRT. CRT's do crack due to sudden temperature changes or a drop, and the crack is so small that it is not seen.

OK.  I will check this out.  I also read that I should try leaving the CC powered on for 24/48 hours (via the back switch) and then try the soft power on key on the keyboard.  Thanks!

 

[Macdrone]

I would double check the connections for sure on the analog board as that single ground wire is very pesky.  Like I said the carriage tabs where the motherboard slides in are notorious for bending into the spot across.

 

[Elfen]

OK.  I will check this out.  I also read that I should try leaving the CC powered on for 24/48 hours (via the back switch) and then try the soft power on key on the keyboard.  Thanks!

I just realized that it would be easier and safer to do this with the side of a key or coin... Vivid thoughts of somebody picking up a 50 pound sledge hammer to lightly tap a CRT screen just entered my brain with disastrous results - LOL!

 

[bibilit]

The CC will boot without a battery anyway, did you try booting without any additional ram sticks (don't remember if you stated this before, but a black screen can also be a ram problem)

 

[mraroid]

bibilit...  I did read that a CC will boot with out a battery.  So I removed the battery, inspected the battery contacts, and then installed the board and tried to boot.  Same issue.

But I did not try booting with out any RAM sticks.  Great tip.  I will try this!  Thanks!

jack

 

[mraroid]

I just realized that it would be easier and safer to do this with the side of a key or coin... Vivid thoughts of somebody picking up a 50 pound sledge hammer to lightly tap a CRT screen just entered my brain with disastrous results - LOL!

Elfen...    Yep, I was not looking for my sledge hammer. .....

In another life, I rebuild old vacuum tube motion picture amplifiers.  I also rebuild old vacuum tube radios (1930s - say mid 1950s).  And once I rebuilt a older TV from the early 1950s.  So nope, I won't hit the CRT with a iron pipe! 
So are you saying, that if I remove the case of the CC, and then turn the power switch on in the rear of the CC, I will see a light or glow from the rear of the CRT?  Or do see this light when I turn on the soft power from the keyboard?
Usually, when I shoot trouble on older vacuum powered electronics, I have a schematic.  So the first thing I do is check for voltages at different places.  I am lost once I hit ICs and flat packs.  But I have a general understanding.
I have no schematic to use to check voltages.  But maybe someone knows some typical places I can pull some DC and at what voltage?  As Uniserver just rebuilt both my analog and log board, I do not suspect bad caps or bad traces.  But I will go over the analog board again under a bright light and a magnifying glass.
 
Thanks!  I will report back tonight.
 
jack

 

[Elfen]

I remember the Color Classic turning on with the switch, but this is the CC-II. So, thinking along the lines of the Performa/LC 550 - 580 the CRT should be on when you press the keyboard switch; at least with the cover off, you should see the tube glow at the back of the neck. Other than being a Trinitron Tube, its a standard Color CRT with 3 electron guns so it should glow visibly.

If the CRT neck is not glowing, then it narrows it down to the tube or the analog board. I'm hoping its the board. A color Trinitron tube that small ought to be murder to get on its own. Anybody out there got a source?

 

[mraroid]

Thanks folks for the many tips....  This is what I have tried in the last 24/48 hours:
 
1) I left the rear power switch on while I was at work and overnight.  Then I turned the soft power switch on via the keyboard.  No joy.
 
2) I removed the analog board and inspected the rear connector under a magnifying glass and high light.  I could not find any problems.  No dust, no dirt, no bent connectors.  While it was out, I gave it yet another quick shot of contact cleaner anyway.  Then I sprayed a little compressed air on it, and let it sit to dry. 

3) While I was in the cleaning mood, I took my can of contact cleaner and sprayed into the socket the analog board sits in. I did this before maybe 6/8 months ago when the CC was totally apart.  After a good spraying, I turned the CC down on a soft towel and let gravity drain out the excess contact cleaner.  I let it set overnight.
 
4) I installed the analog board.  With my hard drive connected, I attached power.  When I turn the power switch on in the rear of the CC, I can here the sound which I believe is the sound of the CRT turning on.
 
5) I press the key on my keyboard to turn on the CC.  I hear the fan spin up.  I received one happy chime.  Nothing on the screen.  Nothing else.
 
I did not try Elen's experiment of removing the case and then apply power, and then turning on the CC with the keyboard.  I need to set this up in the dark so I can see if I can see any light from the CRT.  I hope to try this tonight.
 
While at work, I went surfing on the net to find others who have the same issue.  I read one post about a person who had the same issue as I do.  He found that he had a bad capacitor in his keyboard.  He replaced it and all was well.  I do not have a spar keyboard to swap out.  I have not taken a keyboard apart before. 
 
Should I pull the power on my hard drive, boot, and look for a not happy face on the screen? 
 
Other thoughts? 
 
If it is a analog board issue, I do have working a re caped, and cleaned 575 analog board.  I know I can just slide the analog board in.  But as I understand it, I have to re edit some files, so the 575 analog board can supply 512×384 to my CRT?    I am not sure how much work in involved in converting my CC to 640 X 480.  And I would feel better about doing this 575 upgrade if I have a working CC to start with.
 
Any thoughts?
 
Thanks everyone for hanging in with me for so long.  I am getting close I think.
 
jack
 

 

[mraroid]

The CC will boot without a battery anyway, did you try booting without any additional ram sticks (don't remember if you stated this before, but a black screen can also be a ram problem)

No, I did not try that yet bibilit.  Thanks for the tip.  Remove the battery, and all SIMS?  Leave only the 2 ROM chips in?

jack

 

[Paralel]

If you try everything, and you absolutely have no success, its probably a busted trace inside the board, which you can't see. We have seen that around here every once in a rare while. You can try gently "flexing" the board in one dimension or the other and then see if you can get it to boot right away.

I only suggest this as a last resort, since flexing an older PCB can, in and of itself, be risky.

I have been reading this thread, but my memory is not 100%, have you tried replacing the ROMs with known working ROMs? ROM rot is possible, its rare, but it does happen.