Re: Noob question #1
Hello again, evereybody. I want to close the loop and tell everyone what I found out in regard to repairing the symmetrically shrunken images on my Color Classic and Mac RGB monitor. Boy, we were thinking TOO HARD. I opened the cases and found no burst or dried-out caps. What I -did- find was a complete set of size and geometry trim pots that can only be reached after you take the back cover off. You may recall that Dear Apple gives us access to the vertical and horizontal centering pots from the outside (when the back half of the case is attached). Those two trim pots are merely two of about EIGHT lined up in a nice, clearly labeled row. A twist here, a tweak there, and now I'm good to go! Best, - Marty -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
Re: Noob question #1
On 1/19/06, simon [EMAIL PROTECTED] wrote: most of the times a shrunken size is caused by a broken capacitor. the capacitor could be short circuted or not connected. I suspect a electrolyth (the big ones) if the aspect ratio of the image is still ok (3:4) then this may be in the power section of the analog board. That is -exactly- what is happening in this system. I may replace all of the capacitors on the power section, just as a proactive maintenance step. The largest caps seem to be in the front left quarter of the analog board, as viewed from the rear or the Mac. Is this the right area? (I'll do some googling this weekend and hopefully find a service manual online.) Thanks to all who have responded, I appreciate your input. I -knew- I had come to the right place! - Marty -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
Re: Noob question #1
I've heard of this capacitor plague before. Hmm, replacing some caps does not sound too difficult. - Marty --- Martin Swartz [EMAIL PROTECTED] wrote: Today I have a Color Classic that exhibits a working but shrunken video image. I've seen conflicting opinions about what can cause this... snip On 1/19/06, Gregg Eshelman [EMAIL PROTECTED] wrote: Capacitors in the tube driver circuitry will do that as they age. Not so well sealed electrolytics will either dry up a bit or leak, changing their values. -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
Re: Noob question #1
On 19-jan-06, at 1:31, Martin Swartz wrote: Hello, all - In a previous (business) life I did a lot of support / hacking around with Macs, mostly 1xx Powerbooks and the SE series. Those days are gone. Now I have several questions to ask that relate to Classic Macs as restoration projects. In the corporate days, any one-piece Mac with flaky or failed video was scrapped out. Today I have a Color Classic that exhibits a working but shrunken video image. I've seen conflicting opinions about what can cause this, ranging from cathode ray tubes do this when they get old over to the high voltage circuitry is going bad, not the CRT per se. What's the prevailing wisdom among this group? Can the analog circuitry be tweaked? Does someone build new replacement analog components for a reasonable price? Or is the answer none of the above? most of the times a shrunken size is caused by a broken capacitor. the capacitor could be short circuted or not connected. I suspect a electrolyth (the big ones) if the aspect ratio of the image is still ok (3:4) then this may be in the power section of the analog board. if it is only in one direction then look in the horizontal or vertical deflection sections. Measure in any way the voltage of the power supply and check with the service manual. because you still get a picture there wont be a transistor broken. look visually for burned resistors and check the capacitors in the neighbourhood. a visual good capacitor could still be malfunctioning. -- met vriendelijke groet Simon Claessen [EMAIL PROTECTED] -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
Re: Noob question #1
well... thats just it... when it comes to CRT displays it -can- be
anything... and (i know im not going to gain any friends by saying
this.. but i dont think i have any on this list anyway) the macs
'closed box' design pretty much meant that when one breaks that its
just time to throw it away ('appliance computers' as apple called
them)
now on to the repair (this applies with pretty much any CRT display so
this is the easy part)
simple fixes; im not familiar with SE video displays but there -might-
be adjustments for h-size and v-size (and position) on the inside...
just re-adjust... they may not be labeled so you may have to get a
schematic tho this is doubtful... may also not be present... not sure
what to do there... (never seen a CRT display without height and width
adjustments... even TVs have them)
hight and widht may be on the top (or bottom) of the deflection yoke
hidden under a white or beige 'cap'...
serious problems;
this can also be a hard-to-fix short in the CRT (tho doubtful) or a
tired flyback transformer (high voltage!) a failing HOT (horizontal
output transistor... biggest transistor in the CRT circuitry) flaky B+
('low' voltage) or partial short in the deflection yoke (just
to name a few possibilities i dont know what the display
looks/acts like so i cant narrow it down)
suffice it to say... try looking for and tweaking position/size
adjustments first... (try to avoid adjusting 'linearity'.. else you
will have one funky looking image)
On 18/01/06, Martin Swartz [EMAIL PROTECTED] wrote:
Hello, all -
In a previous (business) life I did a lot of support / hacking around
with Macs, mostly 1xx Powerbooks and the SE series. Those days are
gone. Now I have several questions to ask that relate to Classic Macs
as restoration projects.
In the corporate days, any one-piece Mac with flaky or failed video
was scrapped out. Today I have a Color Classic that exhibits a working
but shrunken video image. I've seen conflicting opinions about what
can cause this, ranging from cathode ray tubes do this when they get
old over to the high voltage circuitry is going bad, not the CRT per
se.
What's the prevailing wisdom among this group? Can the analog
circuitry be tweaked? Does someone build new replacement analog
components for a reasonable price? Or is the answer none of the
above?
Thanks in advance for any advice.
- Marty
--
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http://mephitus.renamon.org/
When you've done something right, no one will be sure you've done
anything at all. -- Futurama
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Re: noob question
you could try the classiccmp.org mailing lists for help. Or even the Electronics_101 yahoo group. Probably other forums on the net besides. __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
Re: Noob question #1
--- Martin Swartz [EMAIL PROTECTED] wrote: Today I have a Color Classic that exhibits a working but shrunken video image. I've seen conflicting opinions about what can cause this, Capacitors in the tube driver circuitry will do that as they age. Not so well sealed electrolytics will either dry up a bit or leak, changing their values. Hmmm, did Apple suffer the same problem as most PC motherboard makers in the mid to late 1990's? In a bit of industrial espionage, a formula for capacitor electrolyte was stolen and ended up in the hands of one or more companies making counterfeit capacitors with the names of legit companies on them. Unfortunately for the buyers of the capacitors, the stolen formula wasn't quite right and eventually caused bulging and leaking. Almost every motherboard manufacturer and OEM PC builder ended up with anywhere from a few thousand to several million bad capacitors installed in their products. (Just now doing a motherboard replacement of one that nearly every cap was bulged and leaking on. Amazingly it still booted but had a bunch of weird problems.) It will be total Fandemonium! August (Fri) 4th, (Sat) 5th (Sun) 6th, 2006 http://www.fandemonium.org __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Vintage Macs is sponsored by http://lowendmac.com/ and... Small Dog Electronicshttp://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac http://lowendmac.com/lists/support.html Vintage Macs list info: http://lowendmac.com/lists/vintagemacs.shtml -- AOL users, remove mailto:; Send list messages to: mailto:vintage.macs@mail.maclaunch.com To unsubscribe, email: mailto:[EMAIL PROTECTED] For digest mode, email: mailto:[EMAIL PROTECTED] Subscription questions: mailto:[EMAIL PROTECTED] Archive: http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/ iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
