daver2
10k Member
A bit more clarification.
I have three boards, all identified as Cromemco DPS-1 Rev B.
I have two cards with THREE 7812 Voltage regulators and ONE 7805 voltage regulator. The THREE 7812 Voltage regulators appear to be configured in parallel. These cards don't have the two diodes fitted to them - and there is a wire link on the underside of the PCB.
The third board is different. It seems to contain TWO off +15V regulators in parallel (each via the two diodes) feeding ONE off +12V regulator and a separate +5V regulator. This card has the two diodes fitted with no wire link on he underside.
All three cards only feed one disk drive.
Can you just double check whether you actually have two +5V regulators (7805) or not on your board?
I suspect someone is over-stressing the regulators on your card by feeding two separate disk drives from one regulator card.
Dave
I have three boards, all identified as Cromemco DPS-1 Rev B.
I have two cards with THREE 7812 Voltage regulators and ONE 7805 voltage regulator. The THREE 7812 Voltage regulators appear to be configured in parallel. These cards don't have the two diodes fitted to them - and there is a wire link on the underside of the PCB.
The third board is different. It seems to contain TWO off +15V regulators in parallel (each via the two diodes) feeding ONE off +12V regulator and a separate +5V regulator. This card has the two diodes fitted with no wire link on he underside.
All three cards only feed one disk drive.
Can you just double check whether you actually have two +5V regulators (7805) or not on your board?
I suspect someone is over-stressing the regulators on your card by feeding two separate disk drives from one regulator card.
Dave