exxos's Atari, Amiga & retro forum

This is my first post, so excuse the crudity :D

I recently purchased an old GoldenImage 3A-1D external floppy drive, but the power supply which came with it is not correct and not to mention dead.

Would anyone be able to help with info to get me going with finding a new power supply?

I am hoping to find the following information:

1) voltage and amperage specs
2) barrel jack size
3) center positive or negative

Any help would be greatly appreciated 8-)

@bfollowell

I'd suggest you take it apart and have a look at the power circuitry, see if you can see what the voltage regulator is and that will give you an idea of the range of input voltages from the datasheet.

While it's apart you can use a multimeter in continuity mode to work out what is ground and what is positive.

I'd suggest if it is anything like my Datel drive it'll take around 9v to 12v in with centre positive, but if you check as I've described above you will be able to confirm easily.

Some have a 7805 regulator build in and when the Floppy Drive have 12V connected too you need a 12V stabilized PowerSupply. I think 1 Ampere max is good

frank.lukas wrote: 31 Mar 2021 17:13 Some have a 7805 regulator build in and when the Floppy Drive have 12V connected too you need a 12V stabilized PowerSupply. I think 1 Ampere max is good

I agree, mine works just fine with 12V 1A, and it has a 7805.

Here is the board (only traces on bottom side) ... I'm looking up all the ICs to find the regulator.


Thank you so much for the advice! Will keep you updated

See the picture ...


May be the regulator is under the pcb? Google a picture from a 7805 ...

the bottom side doesn't have anything aside from traces and I don't see anything that looks like a 7805 :(

I haven't found anything that explicitly says regulator...

HD74LS02P - logic gate TTL
SN74LS14N - Inverter Schmitt Trigger

GD 4510B - up/down decade counter
GD4510B - up/down decade counter

MC14511BCP (FFX09029) - Decoders/Demultiplexers

HD74LS157P - Quadruple 2-line-to-1-line Data Selectors / Multiplexers
(noninverted outputs)

The power input is directly connected to VCC pins on the various 5V ICs, so this needs a 5V (centre positive) input, and it's not regulated further on the board.

Furthermore, it says +5V right next to the white connector on the board, which is also connected to directly to the power input. It also appears to say +12V next to that connector, but that pin is unconnected. I assume this is the DC output for the mechanism, and it does not require +12V. (Typically only very old floppy mechs require the +12V source.)

I want to thank everyone for all of the help! So, update I finally got the new power supply and put the drive back together. It works beautifully.

So, @derkom was right on and it definitely agreed with what I was seeing in the data sheets for the ICs like inverters, etc. for power.

For future reference if anyone need this information for a power supply:

1) Power specs -> 5 V, 500 mA
2) Barrel jack size -> 5.5 mm outer diameter, 2.1 mm inner diameter
3) Center Positive connector orientation

Seabassnash wrote: 05 Apr 2021 21:33 So, update I finally got the new power supply and put the drive back together. It works beautifully.

:thumbup: