I have an old Macintosh Performa 575 and the display is going bad.
When I first turn it on the display has a pink tint.
After about 15 minutes when it warns up the display begins to work okay and is no longer with a pink tint.
Any ideas on that is wrong with the display and how to fix it ?
Could there be a loose part from shipping ?
Sounds like one of the electron guns (in a color CRT you have 3 guns for red, green and blue) is taking longer to power up, in your case, the magebta-tinted image clearly indicates that the green gun is either weak or taking longer to fire up.
If the green gun had failed, the magenta tint would have stuck...
Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]
Reminds me of my dad's old 20" monitor. It was pinkish after power-on each time. Turned out it was a cold solder joint.
After warm-up or after -ahem- *gently* knocking on the chassis, the pink colour tone went away. 😉
Edit: Typo fixed.
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//
The question is: why is the green gun taking longer? Some capacitor going bad and taking longer to pick up a charge? Some solder joint as Jo22 said? Probably needs disassembly... Any service manuals available for this machine?
EDIT: here is at least a slideshow for servicing Performa 5xx: http://tim.id.au/laptops/apple/legacy/perform … _500_series.pdf
I quote:
Predominant color tint or color cannot be adjusted […]
Predominant color tint or color cannot be adjusted
- Perform video adjustments. Refer to “Video” in Adjustments chapter.
- Replace analog board.
- Replace CRT if red, green, or blue cannot be turned off using appropriate controls.
I guess point 2 might be relevant, and instead of replacing there is probably a failing componet on the analog board, like a capacitor.
To add on to what I've previously stated, as a starter I'd first try to reflow the solder joints on the neckboard (the board that you put on the back of the CRT (but be careful of not zapping yourself or accidentally break the neck off!)
If that doesn't work, recapping the analog board (per Root42's suggestion), if even that still does not work, I'm afraid that an analog board replacement will be required.
In the worst case, the CRT itself is faulty, in that case, a tube swap (well, good luck finding a compatible tube) will be the only recourse if all else fails 😵
Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]
All CRT monitors need at least 15-60 minutes to stabilize to "normal" operation actually, depending on CRT model and time duration after the last hardware calibration. Regarding repair, this can usually be solved by hardware calibration, which usually "fixes" these inconsistency, but it is a rather involved process and publicly documented only for later Trinitron/Diamondtron CRTs so you are out of luck here. On those it basically works by modifying the internal EEPROM storing more "deeper" settings and you either need a USB adapter with USB-UART bridge chip (i.e. Silicon Labs CP2102) and special software or CRT with Factory OSD menu to modify the EEPROM data. So I would say be happy it looks okay after warm up, otherwise it would be hard to fix it. The reflows and recaps suggested above may actually fix the underlying cause so it is probably the first thing you could try given you have no option to perform the hardware calibration (which is easier).
I'd reflow the solder joints around the yoke, to the wires from this going to the analogue board.
