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Need help pointing to strange video problem on SE/30
- Thread starter 68kbits
- Start date
volvo242gt
Well-known member
uniserver
Well-known member
√ (1) Check and clean connections between SIMMs (ROM-SIMM) and SIMM (ROM-SIMM) slots, and restart.
√ (2) Remove PDS card(s) such as an accelerator card if installed, and restart.
√ (3) Check the battery. Replace it with a new one if voltage is low, and restart.
√ (4) Replace electrolytic capacitors C6 (1µF 50V) and C7 (47µF 16V) on the logic board with new ones. Surface mount chip type capacitors are soldered on the original logic board. But you can use miniature radial lead type capacitors instead.
Anyway, be carefull about desoldering and soldering procedures not to break circuit patterns on the board. Make sure the polarity of electrolytic capacitors before soldering.
If you find liquid leak or corrosion of other capacitors, it is a good idea to replace them or all electrolytic capacitors with new ones. Macintosh SE/30 was introduced in 1989 and discotinued in 1991. Electrolytic capacitors have been degraded after years.
? (5) If solution (4) doesn't work, pull up the sound IC chip (UB11). You can see letters "SONY 0F09G 3430045B APPLE85" or "SONY 9A04 3430045B APPLE85" printed on the chip. To pull up the IC chip, connect pin 7 to pin 15 of the chip with a 1 kilo ohm resistor.
√ (6) If solution (5) doesn't work either, replace the network filter RP2 (Bourns 4120R-601-250/201).
no dice.
not sure what #5 would do… but already tried 1,2,3,4,6 before posting.
√ (2) Remove PDS card(s) such as an accelerator card if installed, and restart.
√ (3) Check the battery. Replace it with a new one if voltage is low, and restart.
√ (4) Replace electrolytic capacitors C6 (1µF 50V) and C7 (47µF 16V) on the logic board with new ones. Surface mount chip type capacitors are soldered on the original logic board. But you can use miniature radial lead type capacitors instead.
Anyway, be carefull about desoldering and soldering procedures not to break circuit patterns on the board. Make sure the polarity of electrolytic capacitors before soldering.
If you find liquid leak or corrosion of other capacitors, it is a good idea to replace them or all electrolytic capacitors with new ones. Macintosh SE/30 was introduced in 1989 and discotinued in 1991. Electrolytic capacitors have been degraded after years.
? (5) If solution (4) doesn't work, pull up the sound IC chip (UB11). You can see letters "SONY 0F09G 3430045B APPLE85" or "SONY 9A04 3430045B APPLE85" printed on the chip. To pull up the IC chip, connect pin 7 to pin 15 of the chip with a 1 kilo ohm resistor.
√ (6) If solution (5) doesn't work either, replace the network filter RP2 (Bourns 4120R-601-250/201).
no dice.
not sure what #5 would do… but already tried 1,2,3,4,6 before posting.
techknight
Well-known member
Thats what jdw's board does that I have here. I checked all circuits between rom/ram and processor.
I didnt remove the coprocessor
I didnt remove the coprocessor
uniserver
Well-known member
lol did you every try this?
? (5) If solution (4) doesn't work, pull up the sound IC chip (UB11). You can see letters "SONY 0F09G 3430045B APPLE85" or "SONY 9A04 3430045B APPLE85" printed on the chip. To pull up the IC chip, connect pin 7 to pin 15 of the chip with a 1 kilo ohm resistor.
i never tried this… maybe i will give it a shot and see what happens..
? (5) If solution (4) doesn't work, pull up the sound IC chip (UB11). You can see letters "SONY 0F09G 3430045B APPLE85" or "SONY 9A04 3430045B APPLE85" printed on the chip. To pull up the IC chip, connect pin 7 to pin 15 of the chip with a 1 kilo ohm resistor.
i never tried this… maybe i will give it a shot and see what happens..
techknight
Well-known member
I dont think I did. But all that chip does is control RESET management to the CPU, etc...
Well, if you have headphones plugged in. If you press reset, and hear a slight "pip" then the sound IC needs no attention, and also tells you that the RESET function works.
Thats what I did, and that was ok. That also tells me that the ROM was getting far enough to setup sound hardware before taking a nosedive.
Well, if you have headphones plugged in. If you press reset, and hear a slight "pip" then the sound IC needs no attention, and also tells you that the RESET function works.
Thats what I did, and that was ok. That also tells me that the ROM was getting far enough to setup sound hardware before taking a nosedive.
genie_mac
Well-known member
The horizontal lines don't look like a video system problem to me, if it were vertical lines, it would be easier to figure out!
Those SE/30's never cease to amaze with the type of problems you get. A new one every week
PS: does anyone know what the 16Mhz clock signal on the SE/30 is supposed to look like? I assume it would be a nice square wave, but that's not what I'm getting on a faulty board. Can't check against a good board at the moment.
Those SE/30's never cease to amaze with the type of problems you get. A new one every week
PS: does anyone know what the 16Mhz clock signal on the SE/30 is supposed to look like? I assume it would be a nice square wave, but that's not what I'm getting on a faulty board. Can't check against a good board at the moment.
techknight
Well-known member
It is supposed to be a sine wave, surprisingly.
If you didnt have an oscillator you would have no CRT output at all.
If you didnt have an oscillator you would have no CRT output at all.
genie_mac
Well-known member
Really? That's really unusual! But at least I know now that the clock signal is not the problem...nice sine wave at all the chips that need a clock. Had a look at the M68000 datasheet and it specifies CLK as requiring a nice square wave. I wonder how they're getting away with a sine wave, especially as the amplitude is rather low..not much of the wave would be at defined logic high levels. Are there Schmitt triggers inside the chips?
techknight
Well-known member
Every oscillator IC i have seen, puts out a sinewave, or sometimes a really dirty square wave.
As long as your logic circuitry has some sort of hysteresis-shaping tolerant input, (CMOS/TTL different) then waveshape isnt going to matter as it will be a bang-bang style clock interpretation anyway.
or use a schmitt trigger circuit, it usually isnt an issue.
As long as your logic circuitry has some sort of hysteresis-shaping tolerant input, (CMOS/TTL different) then waveshape isnt going to matter as it will be a bang-bang style clock interpretation anyway.
or use a schmitt trigger circuit, it usually isnt an issue.
