SE/30 is voltage adjustable?

[kiag]

I am trying to find how to adjust voltage on the SE/30 power supply. I have found instructions on how to do this on a Mac Plus but can’t find or figure out how to adjust this on an SE/30. If anyone could point me to instructions I would really appreciate it. I am trying to get the SE/30 to boot with Bolle’s adapter and 3 cards (accelerator, Ethernet and video). It will work with any 2 out of the three. The voltage on the 5 volt reads in the 4.5 range with all 3. I actually have 2 power supplies, one Sony and one just labeled Apple, neither recapped. Neither will fully boot with all 3 cards. 
 

Also, is there any way to adjust the 5V independently of the 12 V? I don’t know what the upper limit on he 12V is but I don’t want to cook anything. 
 

Thanks for any help. 
 

 

[davidg5678]

Adjusting the PSU voltage without recapping the PSU first is probably not a good idea. Part of why the voltage is not high enough is because the capacitors have already leaked. Driving the components of the PSU (which are already out of spec) even harder probably will just cause you a big headache later. From what I remember, the voltage rails are both controlled by a single potentiometer. I have linked a video below with instructions for both recapping and adjusting the voltage rails.

I think in this case, it might be best to just replace the Power Supply with a modern one. Some people have had trouble with the PSU driving several PDS cards simultaneously, even after recapping them. You can place a modern power supply inside the computer which has the ability to provide more power than the stock models can.

This video goes over recapping the PSU: https://www.youtube.com/watch?v=nSZ8QsNUxDM&t=2702s

This video goes over replacing the PSU with a modern alternative: https://www.youtube.com/watch?v=hiN7mP9iQxA&t=51s

Good luck!

 

[kiag]

Thank you! Very informative. 

 

[Chopsticks]

you should be mindful of the total wattage of the cards and the se/30 that you are driving. the se/30 psu is only rated to supply so much current and if you tax it to much then you will get voltage drop. there are some meanwell psu units available that will fit inside the original se/30 psu chassis that will output much higher wattage. its one option that would allow you to drive all those cards without needed to worry about power requirements. to be fair driving the se/30 psu hard to the point that the 5v rail is dropping to 4.5v is really a sign that its worth beefing up the power supply with a new modern switch mode psu to cater for your needs