I have replaced the capacitors, resistors and rectifiers but the Atari ST does not power up at all.
Would someone mind looking at the pictures attached to see if I've made any visual mistakes, please?
The power supply was working before I swapped these components out.
Thanks guys! :idea:
SR98 PSU FAILED AFTER RECAP
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tronic
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SR98 PSU FAILED AFTER RECAP
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rubber_jonnie
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Re: SR98 PSU GETS MORE LOVE
@tronic Just so you know, the forum guidelines are that pictures should be placed in-line, so I have done this for you in this instance.
Check the fuse in the plug and mains lead continuity, and the PSU fuse. The white ceramic item is a fusible resistor, checking continuity across that will tell you if it's bad, and also check the switch is still working properly.
Be VERY careful checking voltages on the input side and be aware the heatsinks can also be live. If you can, test it with load resistors rather than plugging into the ST. Are there any voltages at the output?
Check the fuse in the plug and mains lead continuity, and the PSU fuse. The white ceramic item is a fusible resistor, checking continuity across that will tell you if it's bad, and also check the switch is still working properly.
Be VERY careful checking voltages on the input side and be aware the heatsinks can also be live. If you can, test it with load resistors rather than plugging into the ST. Are there any voltages at the output?
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Pacman
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Re: SR98 PSU GETS MORE LOVE
Check to see if all capacitors are placed correctly (+ and -).
Also that you haven't exchanged any capacitors, so they're in the wrong place.
Finally, being a vintage computer there might be potential contact issues (cold solder joints, partly broken PCB traces etc. Check all circuit traces to see, possibly with a magnifier.
Also that you haven't exchanged any capacitors, so they're in the wrong place.
Finally, being a vintage computer there might be potential contact issues (cold solder joints, partly broken PCB traces etc. Check all circuit traces to see, possibly with a magnifier.
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB
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💧Are you a good person? 💧Living Waters
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rubber_jonnie
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Re: SR98 PSU GETS MORE LOVE
I have compared an original SR98 image and the caps are correctly oriented in terms of polarity, but it is worthwhile checking the values are correct.
As @Pacman mentioned, check the PCB for signs of damage and solder bridges.
As @Pacman mentioned, check the PCB for signs of damage and solder bridges.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Steve
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Re: SR98 PSU GETS MORE LOVE
Take a photo of the underside....
Also double check +/- for the rectifier....
And check the fuse! :)
Also double check +/- for the rectifier....
And check the fuse! :)
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Tomswork
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Re: SR98 PSU GETS MORE LOVE
My favorite in these power supplies is the diodes that like to be resistors
Tom
Tom
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exxos
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Re: SR98 PSU FAILED AFTER RECAP
I have split this topic as it is a hardware issues topic not a tweaks and fixes topic!
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exxos
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Re: SR98 PSU FAILED AFTER RECAP
If this was one of my kits, have you swapped the diode pack on the right hand heatsink ? A few people have changed the one on the left with it, which is wrong. Though I would have thought it would have gone BANG if that was the case.
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Tomswork
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Re: SR98 PSU FAILED AFTER RECAP
Ok maybe my eye sight but the diode on the dc side looks like the leg is cut
Tom
Tom
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WiseGreasyBastard
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Re: SR98 PSU FAILED AFTER RECAP
R101 would be my first check. Check it hasn't gone OC.
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