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#1 2014-09-04 10:16:10

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Colour Classic Analog Board Repair

My Colour Classic has never worked all that well. The CRT has always been unstable - flickering, varying in brightness, the raster produces irregular shapes, and it's almost impossible to adjust it to be perfectly aligned with the bezel.

Today, when powering it on, the hard drive clicked on and off repeatedly. After a few minutes, the drive spun up successfully and booted into System 7. Whenever accessing the disk though, the CRT would flicker or vary in brightness.

It's almost like the voltage is dipping too low, but the problem gradually gets better as the components warm up.

I took a couple of short videos to demonstrate the problem.


Some communities have recommended modifying the machine to instead use a Macintosh LC575 Analog Board since it's a little more reliable, but finding an LC575 Analog Board around here is about as likely as finding another Colour Classic.

I've worked on Analog Boards for early Compacts before, but the CC's board is a completely different beast.

Any ideas what could produce this issue?

Last edited by iMic (2014-09-13 11:59:14)


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#2 2014-09-04 12:05:51

techknight
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Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

Caps.....

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#3 2014-09-04 15:05:43

macdrone
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From: Rainier, Or
Registered: 2014-05-25
Posts: 219

Re: Colour Classic Analog Board Repair

Caps on the analog board.  It's time. I have one that will randomly just shut off.  I need to get hot on it myself.

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#4 2014-09-04 15:07:13

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

Nice and simple repair then. I'll take the Analog Board out and start compiling a list of caps over the weekend.


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#5 2014-09-04 16:47:28

techknight
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Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

The ones inside the video amplifier can seem to go first

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#6 2014-09-04 17:24:04

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: Colour Classic Analog Board Repair

Let us know the analog board cap list.  I should probably recap my CC's analog board at some point too.  I already did the logic board.

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#7 2014-09-09 02:07:33

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

I haven't had the chance to yet, but I'll document every capacitor I can see on both the Analog Board and Logic Board while I have it apart. I'll grab some photos if I can as well.


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Faculty of Macintosh Restorations & Modifications - "It works, let's fix it!"

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#8 2014-09-09 15:02:21

jt
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From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,376

Re: Colour Classic Analog Board Repair

Caps! -- Macintosh Color Classic

Last edited by jt (2014-09-09 16:20:43)

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#9 2014-09-09 17:16:15

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: Colour Classic Analog Board Repair

That doesn't include analog board, afaict.

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#10 2014-09-13 11:22:03

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

Open these in a new tab for hi-resolution versions.


Q1rpu0h.jpg

KN5IQyW.jpg


Analog Board Capacitor List

0.47uF 100v, 85c	[x1]
1uF 50v, 85c		[x11]
2.2uF 100v, 85c		[x2]
2.2uF 200v, 85c		[x4]
4.7uF 50v, 85c		[x1]
10uF 100v, 85c		[x1]
10uF 250v, 85c		[x1]
47uF 100v, 105c 	[x1]
100uF 6.3v, 85c		[x1]
100uF 25v, 85c		[x7]
100uF 100v, 105c	[x2]
220uF 25v, 85c		[x1]
220uF 35v, 85c		[x1]
330uF 400v, 85c 	[x1]
470uF 25v, 85c		[x2]
470uF 35v, 85c		[x1]
1000uF 10v, 105c	[x1]
1000uF 16v, 85c 	[x1]
1000uF 16v, 105c	[x1]
1000uF 35v, 85c 	[x1]
3300uF 16v, 85c 	[x1]
3300uF 16v, 105c	[x2]
5600uF 10v, 105c	[x2]

Total Caps on Board: 47

Logic Board Capacitor List

10uF 16v	[x1]
47uF 16v	[x6]
100uF 6v	[x2]

Total Caps on Board: 9


As for my machine, I believe I found the problem.

oeVrhMP.jpg

This 3300uF 16v, 85c low height capacitor has spilled its contents all over the board and onto the surrounding components. Looks like it'll need to be replaced.


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Faculty of Macintosh Restorations & Modifications - "It works, let's fix it!"

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#11 2014-09-13 13:58:53

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: Colour Classic Analog Board Repair

Awesome, thanks iMic.

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#12 2014-09-13 22:14:33

techknight
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Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

I added some important details to the analog board photo if thats ok.

Q1rpu0h.jpg?dl=0

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#13 2014-09-14 06:57:53

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

Of course it's ok, these are great additions to know. Seeing that the bad capacitor is in the Scan Voltage Supply Filters does explain the behaviour on my faulty CC.


I've been looking at element14 for the capacitors. I've been matching the voltages, capacitance and temperatures and choosing the most cost effective replacements from either Panasonic, Nichicon or United Chemicon.

They have all capacitors in stock except the large 330uF 400v capacitor. They also require that some capacitors be bought in packs of 5, so there's a few leftovers.

I'm considering consolidating them down - e.g. instead of ordering 10uF 100v and 10uF 250v capacitors, I'll instead just opt for the 250v ones. Any capacitors that come in 85c and 105c versions - just order the 105c versions. This should reduce costs somewhat since I'm already ordering 5 packs of some of them anyway. Would there be any issues in doing this?

Also, are there some capacitors on the board that I need to be aware of in terms of replacements? Certain capacitors that need specific properties or ones that I should be beefing up from stock during the repair process?


Resident Professor of Alternative Methodology
Faculty of Macintosh Restorations & Modifications - "It works, let's fix it!"

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#14 2014-09-14 16:58:15

techknight
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Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

Your doing ok ;-)

But you do need to pay attention to that short fat capacitor near the zener diodes that love to put off serious heat. Piss-poor engineering sticking a fluid filled capacitor to high-heat items. but I digress...

Get a replacement capacitor that has the longest life at its highest rating.

Last edited by techknight (2014-09-14 16:59:08)

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#15 2014-09-14 17:10:06

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

techknight wrote:

But you do need to pay attention to that short fat capacitor near the zener diodes that love to put off serious heat. Piss-poor engineering sticking a fluid filled capacitor to high-heat items. but I digress...

Get a replacement capacitor that has the longest life at its highest rating.

We're talking the one I have pictured that's blown, correct?

I'm having a difficult time finding a shorter capacitor in that space anyway, so I may have to mount a taller replacement horizontally and use hot glue to space it away from the board and prevent it from moving. I may be able to do something about the heat issue in that case.

Also, looking at the picture above of the blown cap, I may have to replace the resistors around it since they look pretty cooked. Hopefully the coloured lines are still intact and readable once they're cleaned up, but I'm not optimistic that they will be.


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Faculty of Macintosh Restorations & Modifications - "It works, let's fix it!"

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#16 2014-09-14 19:35:33

techknight
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Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

I would say the heat from the resistors, and electrolyte eventually attacked the resistors.

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#17 2014-09-16 10:15:04

uniserver
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From: Sf, Mi
Registered: 2014-05-15
Posts: 954
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Re: Colour Classic Analog Board Repair

wow iMic

Beautiful…  man it would be fantastic if you could do more of this kind of layout/format. good job.


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#18 2014-10-11 19:19:08

Earspray
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Registered: 2014-10-11
Posts: 5

Re: Colour Classic Analog Board Repair

Hi,

I have a Classic Colour that suffers from the same problems.
I had a great picture, but recently the picture flickered between bright & large (too bright, too large) and its normal status. And with the time it has been worse than ever. Well I have on the analog board the same problem than iMic, with resistors that seem burned…
Thank you for the analog board caps list. It will be helpful to rescue my lovely Classic Colour.

Well done !

Last edited by Earspray (2014-10-18 08:46:24)

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#19 2014-10-12 13:15:11

MinerAl
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From: The not-so-great plains
Registered: 2014-08-26
Posts: 69

Re: Colour Classic Analog Board Repair

Peripheral to this discussion of caps, what's going on under that metal shield in the upper right corner?  Is that the video circuitry?

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#20 2014-10-12 13:33:31

techknight
Member
Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

MinerAl wrote:

Peripheral to this discussion of caps, what's going on under that metal shield in the upper right corner?  Is that the video circuitry?

No. that a signal noise shield, all the I/O in and out of the analog board go through there.

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#21 2014-10-12 15:43:30

iMic
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From: Adelaide, Australia
Registered: 2014-05-12
Posts: 877
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Re: Colour Classic Analog Board Repair

Earspray wrote:

Hi,

I have a Classic Colour that suffers from the same problems.
I had a great picture, but recently the picture flickered between bright & large (too bright, too large) and its normal status. And with the time it has been worse that ever. Well I have on the analog board the same problem than iMic, with resistors that seem burned…
Thank you for the analog board caps list. It will b helpful to rescue my lovely Classic Colour.

Well done !


Glad this was of some use to you, hopefully you can get that Colour Classic working perfectly again. smile


Resident Professor of Alternative Methodology
Faculty of Macintosh Restorations & Modifications - "It works, let's fix it!"

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#22 2014-10-13 08:48:36

uniserver
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From: Sf, Mi
Registered: 2014-05-15
Posts: 954
Website

Re: Colour Classic Analog Board Repair

its a shame those 230v CC A/B's go like that… kinda nasty!


#I Re-Cap √Mac √NeTX √Amiga Boards - A/B - PSU# (MacCaps.com)  Modern SCSI HD's - For Old Macs - Pre Cfg'd - 10k RPM! 73gb!! $50 + free shipping  -- Mac 128K Re-Ram kits (16 Chips) $35 + shipping, Floppy Issues?-> Bourns Filter Solution 128k - SE/30, $16 + shipping

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#23 2014-10-18 08:45:38

Earspray
Member
Registered: 2014-10-11
Posts: 5

Re: Colour Classic Analog Board Repair

Hi everyone,
trying to work even with a bright and bad picture on the screen in order to reinstall a new system on a 700 mo SCSI internal drive, the display came suddenly black, with only a white & bright horizontal line. The CC was still on…
The Analog board seems to have suffered a little bit more than previously described (see my post above).

I found this : interesting.

http://www.colourclassicfaq.com/tech/ccparts.html

Now I have 2 CC : one with a Logic Board that is OK, an analog board with display problem ;
One with a dead Logic Board and a dead analog board (even if it looks pristine, I can only hear a little sound when I switch on the power, but no start up at all with the working logic board)…
:-(

Last edited by Earspray (2014-10-23 06:55:30)

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#24 2014-10-23 07:00:09

Earspray
Member
Registered: 2014-10-11
Posts: 5

Re: Colour Classic Analog Board Repair

Hi everyone,

there are 2 diodes, DL21 & DL22, located just behind the 3300 uF 16V 85C. Does anyone know what kind/type of diodes it is ?
Because mines seem to have burned, & they probably have to be replaced.

Thank you in advance

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#25 2014-10-23 14:14:55

techknight
Member
Registered: 2014-05-22
Posts: 449

Re: Colour Classic Analog Board Repair

They are zener diodes. They ALL look this way. Its normal, however it is something they did away with in the lc520+ circuits.

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