# Problem using twin Seagate 7200.9 drives in S1



## donnap (May 2, 2004)

Hi,

Further to my abortive attempt to use 2x Seagate 500gb (7200.9) drives in a UK TiVo here I have been doing a few more experiments with 7200.9 drives.

Unfortunately, it seems as if all the 7200.9 series apart from the 120GB are unsuitable for use in a twin-drive setup in an S1 where both drives are 7200.9s due to the excessive load they put on the puny S1 PSU during spin-up.

In all cases a single 7200.9 is fine and (apart from a 500GB 7200.9 with a 400gb 7200.8) all other combinations of one 7200.9 with other (7200.8 or 7200.7) drives are also fine. But if you put 2x 7200.9 drives (apart from 120GB ones) in an S1 TiVo, they pull the PSU down and the TiVo won't boot - it doesn't even show the "powering up" message 

I tried using a SmartStart from PTVUpgrade to delay spin-up of the "A" drive, but this has no effect (or at least doesn't fix the problem). I guess the Weaknees PowerTrip would be similarly ineffective.

I've tried this with various TiVo boxes and various S1 PSUs and the result is always the same - so I guess it's a limitation of the S1 PSU.

Sadly, as I'm not an electronics expert, that's about the limit of my testing. I have a multimeter but I'm not entirely sure how to use it to diagnose a problem in a switching power supply.

Any advice on where to go from here would be appreciated...


----------



## xnevergiveinx (Apr 5, 2004)

you could always buy something like this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8772236408&ssPageName=ADME:B:EF:US:1









you could use the power supply unit to power the drives, so they don't rely on the tivo psu. i wonder if it would confuse the tivo though...?


----------



## donnap (May 2, 2004)

I've already tried powering the drives from an external source but it doesn't work!

I guess the TiVo's BIOS looks for a voltage cue from the PSU to tell it the drives have finished spinning up.


----------



## 1283 (Sep 8, 2000)

If you're powering the drives with external source, then it shouldn't be a TiVo PSU issue.


----------



## donnap (May 2, 2004)

It doesn't work with both drives powered from the TiVo PSU, but the TiVo does try to boot if I power only the "B" drive from an external PSU.

If I power both drives from an external PSU (eg. a PC, in which, BTW, the drives work fine) then the TiVo won't boot (just like when both drives are on the TiVo PSU).

If it was _nothing _ to do with the TiVo PSU or the drives then it should work with both drives powered externally - but it doesn't.


----------



## 1283 (Sep 8, 2000)

Some switching power supplies require minimum load to work properly. When you power both drives with external source, then most likely the load is too low for the TiVo PSU. I have powered up US Series1 without drive, so the UK Series1 PSU behaves differently.


----------



## donnap (May 2, 2004)

Ahh, but powering both drives externally works just fine with two _non Seagate 7200.9_ drives - which once again points to a problem with these particular drives in combination with the TiVo PSU (or maybe the TiVo BIOS?)

The US and UK S1 PSUs are identical and interchangeable. Both use the Autec UPS61-1004-T


----------

