[mythtv-users] NTSC USB tuners: which ones are out there?

[Mark Wedel]

On 08/29/15 03:51 PM, Gary Buhrmaster wrote:
> On Sat, Aug 29, 2015 at 9:25 PM, James Miller <gajs-f0el at dea.spamcon.org> wrote:
> ..
>> I do recall reading/hearing about overheating and power supply issues with
>> these tuners Gary, but thanks for reiterating that and adding some further
>> detail. These do have good passive ventilation--both the units themselves,
>> as well as their power supplies
>
> Note that the power supplies have (essentially) no ventilation.  They die
> due to (usually) the internal caps exceeding their design limits after
> a few years of usage (if you tear one part, almost always you find the
> caps "blown" or no longer able to meet the specs).  Without a good VOM,
> you are not going to see the ripple voltages.   Try replacing one and
> see if it statistically improves (I should note that I replaced my supplies
> proactively for the follow on rounds of Hauppauge devices (I started
> with the original PVRUSB2), because long experience demonstrated
> that those POS supplies were not worth spending any time with; it does
> not hurt that I could pick up high(er) quality switching supplies for pennies
> on the dollar for "NIB" supplies at a local electronics surplus store).

  I don't know the voltage requirements of the 1950, but if it is something that 
the computers power supply provides (12v or 5v), could you just splice in from 
that (one of the unused hard drive connectors?)

  That is what I did with some 2250's I picked up at a surplus place - they had 
no power supplies (or cases) for that matter, but was not hard to get the 12v 
they needed from the computer itself and just remove one of the PCI filler 
panels to let the cables through.

  This also makes it convenient in that if I powered off the computer itself, 
the associated 2250s also shut off - no extra devices to unplug.

  Of course, you do have to verify that you don't end up overloading the power 
supply in the computer - how likely this is depends on lots of factors, but most 
power supplies can put out a pretty high amperage level at 5 and 12 volts to 
potentially support a lot of hard drives.  But if you are using something like a 
NUC or other small form factor computer, this may not be a very good option.