# Are TiVo power supplies only marginally adequate for drive upgrades?



## L David Matheny (Jan 29, 2011)

I said in an earlier post that an upgrade drive drew less power than the original drive. I must have remembered the drive covers from my Premiere upgrade:

WD1600AVVS: 5VDC .65A, 12VDC .50A 
*WD3200AVVS: 5VDC .65A, 12VDC .50A* 
WD5000AVVS: 5VDC .65A, 12VDC .50A 
WD5000AVCS: 5VDC .65A, 12VDC .50A 
WD10EVCS: 5VDC .70A, 12VDC .55A (online photo) 
WD10EVDS: 5VDC .70A, 12VDC .55A 
WD10EARS: 5VDC .70A, 12VDC .55A (online photo) 
*WD20EVDS: 5VDC .60A, 12VDC .45A* (online photo) 
WD20EARS: 5VDC .70A, 12VDC .55A (bought later, AF) 
WD20EURS: 5VDC .70A, 12VDC .55A (online photo, AF)

But does the WD20EVDS really draw less power? Here are some published "Average power requirements" specs (mostly 12V?):

WD1600AVVS: 4.7W read/write, 2.3W idle (all 3 pdfs, 8MB) 
WD3200AVVS: 4.7W read/write, 2.3W idle (all 3 pdfs, 8MB) 
WD5000AVVS: 5.4W read/write, 2.5W idle (Feb 2009 pdf, 8MB) 
WD5000AVCS: 4.1W read/write, 3.7W idle (2011-12 pdfs, 16MB) 
WD10EVDS: 5.4W read/write, 2.8W idle (Feb 2009 pdf, 32MB) 
WD10EVDS: 4.9W read/write, 4.2W idle (2011-12 pdfs, 32MB) 
WD10EARS: 5.3W read/write, 3.3W idle (2011-12 pdfs, 64MB, AF) 
WD10EURX: 5.3W read/write, 3.3W idle (Feb 2012 pdf, 64MB, AF, SATA3) 
*WD20EVDS: 5.9W read/write, 4.9W idle* (Jan 2011 pdf, 32MB) 
WD20EARS: 5.3W read/write, 3.3W idle (Jan 2012 pdf, 64MB, AF) 
WD20EURS: 5.3W read/write, 4.8W idle (2011-12 pdfs, 64MB, AF)

I don't understand some of the variation above. 2TB drives do draw more power than the original drives, especially when idle (but TiVo is always reading and writing). Does TiVo install a larger PS in Elites than in other TiVos? If not, should they? If so, will the more robust units fit in other Premieres, and are they available for purchase? WeaKnees says their Premiere and P-XL PS's are "NOT Compatible with Premiere Elite", and they don't list one for the Elite. If TiVo PS's don't have much spare capacity, could that explain why we have problems with them failing? Do TiVos that have been upgraded seem to have a greater chance of PS failure? Can anything be done to improve a PS, like maybe bigger or better heatsinks?


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## unitron (Apr 28, 2006)

L David Matheny said:


> I said in an earlier post that an upgrade drive drew less power than the original drive. I must have remembered the drive covers from my Premiere upgrade:
> 
> WD1600AVVS: 5VDC .65A, 12VDC .50A
> *WD3200AVVS: 5VDC .65A, 12VDC .50A*
> ...


I'm having difficulty understanding how a drive that draws a lower amperage than the stock drive could use more power than the stock drive, but even if true I'd expect the stock power supply to have at least 2 more Watts of headroom.


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## lillevig (Dec 7, 2010)

Based on those numbers, Western Digital has created the Holy Grail of power generation - more power out than energy consumed. Time to rearrange my stock portfolio. But seriously folks, I agree with Unitron that it's highly unlikely that Tivo would build their power supplies to be capable of only marginally more output than necessary. Thousands of satisfied hard drive upgraders can't all be wrong.


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## unitron (Apr 28, 2006)

lillevig said:


> Based on those numbers, Western Digital has created the Holy Grail of power generation - more power out than energy consumed. Time to rearrange my stock portfolio. But seriously folks, I agree with Unitron that it's highly unlikely that Tivo would build their power supplies to be capable of only marginally more output than necessary. Thousands of satisfied hard drive upgraders can't all be wrong.


Of course, those power supplies being capable of easily handling a slightly more power hungry drive depends on them not having capacitors with the counterfeit secret sauce inside. When one or more of those go bad, it doesn't matter how good the supply's specs were.


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## lillevig (Dec 7, 2010)

unitron said:


> ...counterfeit secret sauce inside.


Uh-oh. I had a Big Mac today. You don't suppose...


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## unitron (Apr 28, 2006)

lillevig said:


> Uh-oh. I had a Big Mac today. You don't suppose...


Yes, that Big Mac will soon cause you to bulge and emit noxious gasses.


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## CoxInPHX (Jan 14, 2011)

L David Matheny said:


> WeaKnees says their Premiere and P-XL PS's are "NOT Compatible with Premiere Elite", and they don't list one for the Elite. If TiVo PS's don't have much spare capacity, could that explain why we have problems with them failing? Do TiVos that have been upgraded seem to have a greater chance of PS failure? Can anything be done to improve a PS, like maybe bigger or better heatsinks?


The reason the Elite cannot use Weeknees Replacement Premiere Power Supply is most likely due to different layout and wiring config. It will be interesting to see an inside pic of the new 500GB Premiere, to see its PS.

After reading this I am tempted to purchase a $50 Premiere just for the spare parts, and put it away.

Note: the Premiere HDD power comes directly from the PS, while the Elite HDD power comes off the motherboard.

*WeeKnees Premiere Power Supply*









*Premiere*









*Elite*


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## steve614 (May 1, 2006)

That is interesting.

So instead of having the power supply create the different voltages needed for the various components, it looks like it puts out a single voltage and the motherboard takes care of the distribution.


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## unitron (Apr 28, 2006)

steve614 said:


> That is interesting.
> 
> So instead of having the power supply create the different voltages needed for the various components, it looks like it puts out a single voltage and the motherboard takes care of the distribution.


I assume you are referring strictly to the bottom picture, the Elite, where it appears the power supply provides +12V (yellow wire) and the motherboard derives a +5V rail from that (red wire to hard drive).

I'm guessing that black thing to the left of the coin cell is the semiconductor involved.

The regular Premiere supply seems to have both the +5V and the +12V outputs onboard, and apparently the S4 platform doesn't need a 3.3V section.


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## steve614 (May 1, 2006)

Yep, I was referring to the picture of the Elite.

The armchair engineer in me wonders how that extra space can be taken advantage of.


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## unitron (Apr 28, 2006)

steve614 said:


> Yep, I was referring to the picture of the Elite.
> 
> The armchair engineer in me wonders how that extra space can be taken advantage of.


Perhaps the way they're doing it now, allowing airflow.

(yeah, I know, where's the fun in that?)


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## lillevig (Dec 7, 2010)

This thread made me take a close look at a drive I had planned to put into one of my older S2 boxes. I had used this drive successfully for a few weeks in an S2DT but had second thoughts about putting it into the S2 240. The reason? The +5 current requirement was slightly higher than typical stock Tivo drives but the +12 requirement was double. I checked ratings on stock Tivo drives of 40GB, 80GB, 160GB, and 320GB.


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## lillevig (Dec 7, 2010)

Interesting footnote: I found one of the Tivo vendors sells a dual power supply delayed power connector that starts one drive, waits 7 seconds, and then starts the other drive. They advertise this specifically for most Model 2 Tivos which they say have power supplies rated at only 38 watts. The other Tivo models, they say, have supplies rated at 61-78 watts.


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## Jonathan_S (Oct 23, 2001)

lillevig said:


> Interesting footnote: I found one of the Tivo vendors sells a dual power supply delayed power connector that starts one drive, waits 7 seconds, and then starts the other drive. They advertise this specifically for most Model 2 Tivos which they say have power supplies rated at only 38 watts. The other Tivo models, they say, have supplies rated at 61-78 watts.


I remember those; just be carefull to hook it up correctly. You want the boot drive to spin up 2nd.

Get it backwards and you've got a race condition. If the second drive didn't spin up before the TiVo was booted far enough to look for it _every single time_ scary things happend. (Can't remember if TiVo failed to boot or just booted to an empty now playing list. Either way, not good)


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## lillevig (Dec 7, 2010)

Jonathan_S said:


> I remember those; just be carefull to hook it up correctly. You want the boot drive to spin up 2nd.
> 
> Get it backwards and you've got a race condition. If the second drive didn't spin up before the TiVo was booted far enough to look for it _every single time_ scary things happend. (Can't remember if TiVo failed to boot or just booted to an empty now playing list. Either way, not good)


Makes sense. I'm not really looking to add a second drive to an S2 but I was glad to finally find some power supply rating info for Tivos. I still don't know if the power consumption numbers on the drives are for start up or steady state so I guess I'll have to rig up a cable so I can measure it.


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