i tried building the circuit for seagate terminal, the one shown below:

however, in hyperterminal nothing ever comes up. am i using the right settings? i've got it set at baud of 9600, No Parity, 1 Stop bit, No flow control.
On the hard-drive itself, i'm connecting to the two pins which are not listed on the jumper table of the HDD label. (second to the right when PCB is facing upward) is that correct?

please help.. i've been trying for 16 hours straight and getting nowhere. i have checked the circuit countless times, rebuilt it 5 times... but still no luck. (note: i have been trying it with functioning drives, not broken ones).

Have you tested your new circuit? Mistakes are easily made, and sometimes parts substitutions don't work as planned. If you short the TX and RX lines (At pins 11 and 12 of the Max232), you should see what you type.

If the circuit doesn't work, here's a few things to check:

Are you getting 5V on the output of the 78L05?
If not, what DC voltage to you have going into it?
Do you have the 1uF capacitors in the right way?
Have you tried it without the two Zener Diodes on the Tx and Rx line?
Have you tried it with a short across the 1K resistor on the Tx line?
Are you sure you have the serial connector wired up right? It's easy to reverse.
Can you try another Max232?
Have you used substitutes for any of the components?

Also, this circuit steals power from the serial port. Usually, this is fine, but some computers don't supply standard voltages on the serial port (Laptops especially). If you're not getting +5V, this could be why.

Maybe easier to buy one, i looked on ebay none found. Somebody may post a link here, if they are on ebay to buy.

I purchased this one on EBay about a year ago. The seller is still selling the same unit.

Auction: 120267956527

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Buy your friends Toshiba\Hitachi and your enemies Seagate.

Have you ever used HD Doctor for Seagate ? It has Voltage/Current Protect System. I would like to offer more details.

Regards

Laura

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SalvationDATA--Profesionnal Hard drive solution Provider. MSN: sales.laura@salvationdata.com

thanks. i followed your suggestion and found a problem with my 78L05 chip. so i've got it working now.