MB-6582 Base PCB J73 Question

[Rowan]

Hi All,

I’m getting prepared to build a MB-6582, studying all the documentation. I have found something that is a bit confusing and wanted to check for the answer long before I come to the problem…

The MB-6582 Base PCB Construction Guide Sates in the PSB B option section jumper J73 should be bridged for PSU B

http://www.midibox.org/dokuwiki/doku.php?id=wilba_mb_6582_base_pcb_construction_guide

But in the MB-6582 Base PSB Parts Guide this is contradicted.

http://www.midibox.org/dokuwiki/doku.php?id=wilba_mb_6582_parts_list

Note 3 at the bottom states that J73 should only be used for PSU C.

Which is correct?

Thanks,

Rowan

[smashtv]

We definitely need to find a way to explain this better in the wiki - if anyone has any suggestions please post!

 

Short answer:

If your PSU generates regulated 5v, fit a jumper @ J73/connect pins 1 & 2 of J73 to each other.

 

If your PSU generates unregulated 5v, wire J73:pin1 to J74:pin1 and wire J73:pin2 to J74:pin2.  You will also need to fit C13, C14, and V4.

 

Long answer:

Regulated 5v input:

The 5v rail comes in @ J1, routes through the power switch, then a jumper at J73 ties the 5v rail to all of the 5v traces on the board.

5v path=green:

 

Unregulated 5v input:

The 5v rail comes in @ J1, routes through the power switch, then a wire from J73:pin2 to J74:pin2 takes it through V4 to give regulated 5v at J74:pin1.  A wire from J74:pin1 to J73:pin1 connects that regulated output from V4 to all of the 5v traces on the board.

5v path=green/wires=yellow:

 

Best regards

 

Tim

[Rowan]

Thanks for the explanation, that makes sense.

 

I’m going for PSU option B with a C64 PSU, If I understand this correctly I should close jumper J73 as the C64 PSU provides has a regulated 5V supply?

 

Regards,

 

Rowan