DM800 Whatever happens after 18 months

BEBI

Registered
Messages
4
BEBI said:
Whatever happens after 18 months of exploitation of DM800 HD [with and without a cooling fan]?!?

There are three versions of DM800 HD PVR:
1) original versions with a serious flaw - overheating [small series], as seen here:
tuner1.jpg

2) with an attached external capacitor to remedy the flaw, as seen below
3) the capacitor is integrated into the tuner

Below, we have the first version of the tuner, REV:J, withdrawn by DMM, then modified [as you will see a bit later on, with a 22uF capacitor and a 220 Ohm resistor], plus the third version, REV:K, which has an added SMD capacitor built into the board, as seen on the image.


dm800revjik.jpg


Just so there's no "you're imagining things".... from the tribal lot... :rolleyes:

Here, we shall compare 2 DM800 HD's from the second series, both from May 2008, with a modified tuner, the ones with an added 22uF capacitor under the tuner itself, modified by DMM.

The first image is a measurement of internal resistance with ESR meter. It was taken in DM800 with an internal 12cm cooling fan, added by me, after 18 months of exploitation. As one can see, the value is 1.3 Ohm, slightly higher than a brand new one.

18mjsaventilatorom.jpg


http://wiki.xtronics.com/index.php/Capacitors_and_ESR - see the detailed info here

The second image shows a second DM800 HD tuner, also used for 18 months but without any cooling fan installed.

It's a disastrous state of affairs: because of the overheating, the internal resistance grew to 64 OHM and the capacity fell from 22uF to 6uF.

The consequence: the infamous "TUNE FAILED" and the disappearance of any signal, which led to a complete malfunction of DiSEqC switch.

Which is why this particular DM800 HD PVR came to me, in the first place. The owner hasn't installed a fan and learned to live with the fact he had to switch the receiver off a few times, in order to finally manage to move to another satellite... until he couldn't move it any more...

18mjbezventilatora.jpg


Back then I advised everybody to install a cooling fan. Those who listened are safe now. Those who didn't - oh, well...

If one decides to change those parts...

One ought to be very careful, as there is a tiny resistor [220 OHM], that must be removed before you change the capacitor and then returned, once the new one is in place. Its lower part attaches to the transistor and the other to the capacitor itself.

Here it is, so one doesn't say "I wasn't warned"...

dm800tuner220ohma.jpg


One more observation: the seriously loudly advertised OLED display has a bit of a shortcoming - it doesn't last! Here is an image so one can judge for oneself. Btw, have a look at yours. I bet it doesn't look any better....

dm800displayostecenja.jpg

:scream:

Translated by me... and slightly improved it, too - with a few more details than in the original post, having bothered the author on MSN, Gawd help me... :rolleyes: :p :D

THNX gorski for translated ;)
 
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grizzlyt

Senior Member
Messages
108
You could also post the new "original" remote controls from DMM, they look like the cloned ones now.

I guess Dream MM likes to sell junk and the people buy it no matter what.

The problems with the tuners is well known and I said that long ago in the Ihad and other forums.

Thanx for the images, it shows really good what a shitty machine this receiver was and still is.
 

gorski

Well Known Member
Messages
1,553
Indeed, grizly!

Can anyone move this thread to the proper section, please: DM800, not 8000 - as I said, Bebi misplaced it...
 

gorski

Well Known Member
Messages
1,553
Here is a bit more helpful info, this time re. DB500s:

service could not be found

replace Q72 Transistor Type P-Channel Logic ref Part No.NDS352APCT-ND (Voltage-Rated 30 V
Current Rating 900mA) = F70 < amp 0.5


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:)
 

gorski

Well Known Member
Messages
1,553
From what we have seen higher temperatures are bad for your bits and bobs, so a fan is good!

Look here, you do not have to be a pro to do it, just use some old meshed wire, a fan, bit of glue and voila...

attachment.php


...and if you want more, a thermostat from a radiator, as described below, does the trick... :party:

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