Click here to go to the forum index Click here for the home page
 
Author Message

<  Bugs  ~  PSU repair [expired thread]

Page 3 of 100
Goto page Previous  1, 2, 3, 4 ... 98, 99, 100  Next
g.lloyd
Posted: Fri Dec 28, 2007 5:11 pm Reply with quote
Regular contributor Joined: 11 Jul 2006 Posts: 36
It is with the drive disconnected.
Yes it's the original drive.
No not tried the drive in a PC but have run it/am running it on a PC PSU and it works fine but does not look very pretty at the moment. New PSU board should be here by Monday.

_________________
George
TF5800t, IA On, TS On, F/W: Buggy Series Link F/W 14/4/2009 -AbTe+Vr
TAPs: EPGnavigator v5.1b; MyInfo B5.5; DescriptionExtender 2.22;
Sig generated by MyInfo on 6/6/11
View user's profile Send private message
Andy K
Posted: Fri Dec 28, 2007 6:55 pm Reply with quote
Frequent contributor Joined: 14 Jun 2005 Posts: 3520
g.lloyd wrote:
but have run it/am running it on a PC PSU and it works fine but does not look very pretty at the moment.


Laughing Laughing Razz

_________________
Autostart TAPs: Jags 3, Bookmark 2uk, Quickjump 1.71, Power Manager 1.1, Description Extender 1.5/2.1, MEI2Archive 3.8l6, Tap Launcher 3.5a, Tap Commander, AccurateBMExtend 0.3, RemoteExt 1.5, TunerRecAR.2
Launched during EPG scan: Crid, SeriesLink 0.35
TF5800 Version 5.13.65 PHT2UFXp5Xw3RpPcE2Bf2BqRsRh3Pf1Ec2ErEfHe1 Ra3Cf2Ct
Samsung 400Gb+Fan
View user's profile Send private message
MikB
Posted: Sat Dec 29, 2007 2:48 pm Reply with quote
Frequent contributor Joined: 23 Sep 2006 Posts: 286 Location: West Midlands
MikeyP wrote:

they aren't dying of old age IMO , they are simply ocassional dodgy ones in a batch IMHO
as I also have a scrap PSU here (from someones on here that failed) , the caps do not show any signs of real old age , tops aren't bulged in any way , they don't stink of cat**** and they haven't leaked in any other way. Wink


That's a different failure mode. Bulging and leaking is connected to either a wrongly specced/installed part (reverse polarity, overvoltage) - and usually fails fairly quickly. Alternatively, you're thinking of the "badcaps" fiasco, where some junk knockoff companies made capacitors that had a duff formula, and took out motherboards, powersupplies all over the place.

Most capacitors have a limited lifetime, the manufacturers quote it in hours, dependent on temperature and stress. Eventually, all electrolytics start to wander from their "nominal" value, ESR etc. That's when things get messy. There is usually NO external visual sign that the cap has failed, and even a capacitor tester (value in uF) won't show up much. An ESR meter will tell you that the capacitor is not up to scratch.

Quote:
If the caps 'go' , is there a likelyhood that something else could be damaged due to the psu outputting wierd voltages, or is that the voltages creep downwards until their below limits for the mobo & HDD?


There are two alternatives: The voltage goes up, or down.

In the Toppy, most people report the voltage going DOWN, and the hard drive shutting down/resetting in protest. In my experience, gradual failure of the electrolytics in the output stage goes that way.

If the voltage goes up -- well, a properly designed PSU has a crowbar circuit. Its job is to sense when the +5v line hits ... 5.5? 6.0? Whatever they've decided is too much. At that point, it shorts out the voltage rail and shuts down the PSU. So the items downstream, powered by the PSU, are safe.

I've not looked at the toppy PSU/schematic. Is there a crowbar
circuit?
View user's profile Send private message Visit poster's website
MikeyP
Posted: Sun Dec 30, 2007 3:19 pm Reply with quote
Frequent contributor Joined: 17 Jan 2006 Posts: 4818
they are just **** caps random fitted to production in a random way Wink

either that or there is a certain batch of toppys out there with duff caps waiting to fail.?
Like I say, mines had a battering over the last 2 years and shows no sign of failure.
the PSU I have here was from one just out of warranty so you can't blame old age. We'd have a lot more failures than at present reported on here.

PS bulging can and does happen when the cap is run in overhot conditions and it dries out (perfectly specced for the app in other ways , just **** caps)

no crowbar , just overvolt feedback via an opto to the switcher IC (it effectively disables the switcher) on the hot side

_________________
www.mpavservice.co.uk
www.mpavservice.co.uk
www.mpavservice.co.uk
Parts or Repair service for your poorly toppy/PSU - 'talk to me' Smile my name's Mike though, not Terry Tibbs Very Happy
View user's profile Send private message Visit poster's website
g.lloyd
Posted: Mon Dec 31, 2007 4:36 pm Reply with quote
Regular contributor Joined: 11 Jul 2006 Posts: 36
Word of warning if you order a new PSU - The connectors are different on the new PSU boards so you need to be handy with a soldering iron to swap the cables over if you have an earlier main board.

_________________
George
TF5800t, IA On, TS On, F/W: Buggy Series Link F/W 14/4/2009 -AbTe+Vr
TAPs: EPGnavigator v5.1b; MyInfo B5.5; DescriptionExtender 2.22;
Sig generated by MyInfo on 6/6/11
View user's profile Send private message
kpee51
Posted: Tue Jan 01, 2008 12:29 pm Reply with quote
Regular contributor Joined: 02 Nov 2007 Posts: 69 Location: Hoddesdon, UK, Crystal Palace TX
Having worked in electronic manufacture for 30+ years and decided to purchase a PVR5800 for Christmas. I decided to look at the internals and was suprised to find average quality (long life) electrolyic capacitors. The ones in my version are ordinary 105 degc 2000 hr units but no worse than found in Humax or any Sky+ box. I've decided that when I return to the workshop in the new year I'll change most to 5000 hr+ types which can be obtained from the likes of RS Components or CPC.

FYI 2000 hrs is 12weeks continuous at 105 degc
for every 10 degrees below 105 the life doubles.


Keith
View user's profile Send private message Send e-mail
jumbo
Posted: Tue Jan 01, 2008 5:50 pm Reply with quote
Frequent contributor Joined: 11 Apr 2005 Posts: 4731
kpee51 wrote:
FYI 2000 hrs is 12weeks continuous at 105 degc
for every 10 degrees below 105 the life doubles.

Keith

Based on this formula and an assumption that the temperature (on average) won't exceed 50 C we get

Continuous use life expectancy = 2^int[(105 - 50)/10] x 12/52 ~ 7 years Shocked

At 60 C ~ 3.5 years, 70 C ~ 2 years, ... HDDInfo temperature never seems to exceed 55 C for me - and presumably that's as hot as it gets?

I'm ready and armed with my spare caps Mad
View user's profile Send private message
rbools
Posted: Fri Jan 04, 2008 11:32 pm Reply with quote
Frequent contributor Joined: 10 Jul 2005 Posts: 448
Having spent nearly 20 years in electronic servicing, the problem we have with electrolytic capacitors is often one particular capacitor failing that is situated physically close to another component mounted on a heatsink (power transistor etc.) and has prematurely aged it. When we find a psu that fails to start we automatically just change any capacitor like this without even bothering to test it first, and this often solves the problem with minimal effort. We'd generally then change most of the other smaller value ones for good measure anyway since these are more prone to go high ESR than larger values primarily used for smoothing.

_________________
TF5800, TS On, F/W: 5.13.65AbB4BfBmBqC0CeCkCpCwCyDeEcEeEfEpErEsEvEzFFmFsGmHHeHsIKtMMhNfOtPPcPePsRRaReRhRpRsSScSdSlSrStSyT2TdTeTfTpTsUUuUxVdWfXpXwZXl
TAPs: NoExit 1.0; QuickJump 1.72; MyStuff 6.2; EPG2MEI v0.96; Extend v1.7; Font Manager 1.0d; MeiSearch 1.35; Power Manager v2.2; SecCache (UK) v0.4; Surfer v0.14; TAP Commander 1.34; TF5000 Display v1.53; TSSaver v0.5; UK Subtitle 1.9; MyInfo B5.4;
Sig generated by MyInfo TAP on 26/11/10
View user's profile Send private message
Andy K
Posted: Sat Jan 05, 2008 7:54 pm Reply with quote
Frequent contributor Joined: 14 Jun 2005 Posts: 3520
Regarding the capacitor which is close to the hard disk.

When you look from this angle it doesn't look so bad. With the capacitor being at a lower level to the hard disk

http://img.photobucket.com/albums/v321/AndyPK/tpypsucap.jpg


_________________
Autostart TAPs: Jags 3, Bookmark 2uk, Quickjump 1.71, Power Manager 1.1, Description Extender 1.5/2.1, MEI2Archive 3.8l6, Tap Launcher 3.5a, Tap Commander, AccurateBMExtend 0.3, RemoteExt 1.5, TunerRecAR.2
Launched during EPG scan: Crid, SeriesLink 0.35
TF5800 Version 5.13.65 PHT2UFXp5Xw3RpPcE2Bf2BqRsRh3Pf1Ec2ErEfHe1 Ra3Cf2Ct
Samsung 400Gb+Fan
View user's profile Send private message
MikeyP
Posted: Sun Jan 06, 2008 3:48 pm Reply with quote
Frequent contributor Joined: 17 Jan 2006 Posts: 4818
Andy K wrote:
Regarding the capacitor which is close to the hard disk.


what about it ?

Quote:

When you look from this angle it doesn't look so bad. With the capacitor being at a lower level to the hard disk


again what about it ? Confused

you mean c23 yeah?

it's out of focus Rolling Eyes Wink

_________________
www.mpavservice.co.uk
www.mpavservice.co.uk
www.mpavservice.co.uk
Parts or Repair service for your poorly toppy/PSU - 'talk to me' Smile my name's Mike though, not Terry Tibbs Very Happy
View user's profile Send private message Visit poster's website
Andy K
Posted: Sun Jan 06, 2008 4:21 pm Reply with quote
Frequent contributor Joined: 14 Jun 2005 Posts: 3520
yes the out of focus brown capacitor Wink

But you get the idea, it's on a different level to the HDD.

From an overhead picture I got the impression it was right next to the HDD.
It's not as bad as I thought

_________________
Autostart TAPs: Jags 3, Bookmark 2uk, Quickjump 1.71, Power Manager 1.1, Description Extender 1.5/2.1, MEI2Archive 3.8l6, Tap Launcher 3.5a, Tap Commander, AccurateBMExtend 0.3, RemoteExt 1.5, TunerRecAR.2
Launched during EPG scan: Crid, SeriesLink 0.35
TF5800 Version 5.13.65 PHT2UFXp5Xw3RpPcE2Bf2BqRsRh3Pf1Ec2ErEfHe1 Ra3Cf2Ct
Samsung 400Gb+Fan
View user's profile Send private message
MikeyP
Posted: Mon Jan 07, 2008 11:03 am Reply with quote
Frequent contributor Joined: 17 Jan 2006 Posts: 4818
ah right - there are other caps next to hotter stuff than the drive itself

this is why I don't think it's overheating (the heat aint helping though) as others would be in a worse state than these two for the drive. (c23 and c22)

_________________
www.mpavservice.co.uk
www.mpavservice.co.uk
www.mpavservice.co.uk
Parts or Repair service for your poorly toppy/PSU - 'talk to me' Smile my name's Mike though, not Terry Tibbs Very Happy
View user's profile Send private message Visit poster's website
ian_c
Posted: Mon Jan 07, 2008 5:54 pm Reply with quote
Joined: 29 Aug 2005 Posts: 9 Location: Warwickshire
Glad that I found this thread. Over the past couple of weeks my mid-2005 Toppy had become very unpredictable, locking up, not responding to remote, etc. My first thought was a firmware / TAP related, and I loaded the the most recent stable versions. This didn?t immediately solve it, and I attempted a factory reset. However, Toppy refused to start up properly and made worrying noises, which I interpreted as a very stressed hard disk mechanism. On further research, I found this thread. I checked the DC supplies to the hard disk., and as others have observed, the 5v supply was reading low; showing 4.55v and fell progressively when left on. All this on a Sunday afternoon. Just time to get to Maplins and buy up their entire stock of 1000mfd electrolytics (three to be precise). As C23 was the easiest to replace I did that first and it seemed to be enough to make Toppy functional, although 5v rail is still low. I chickened out of tackling the others as I didn?t have a circuit diagram, and it was just too speculative. However, I intend to replace other caps when I have better information and more time. Today, I found a discussion on the Australian Topfield Forum http://www.topfield-australia.com.au/phpbb2/viewtopic.php?t=10673&postdays=0&postorder=asc&start=0&sid=b6991996bf1ccba2f4c20d85f30164df. In there is a link to toppytools.com and a power supply circuit diagram. I haven?t checked it against the power supply that I have, but it looks like a good starting point.
View user's profile Send private message
jumbo
Posted: Wed Jan 09, 2008 1:33 am Reply with quote
Frequent contributor Joined: 11 Apr 2005 Posts: 4731
It would be very useful if Turbosat could verify whether or not the faulty PSUs that they have replaced have indeed been due to the "dead" capacitors. Of course they may not have had the time/resources/mandate to repair these units nor to determine the causes of failure. So far the scales are positively tipping toward the capacitors Razz

BTW the Oz link above (ian_c) makes darn interesting reading. Thanks for that!
View user's profile Send private message
MikB
Posted: Sat Jan 12, 2008 11:12 pm Reply with quote
Frequent contributor Joined: 23 Sep 2006 Posts: 286 Location: West Midlands
ian_c wrote:
Just time to get to Maplins and buy up their entire stock of 1000mfd electrolytics (three to be precise).


That is one of the joys of Maplin over the last few years. They seem to have a knack of knowing what quantity you urgently need, and stocking just less than that!
View user's profile Send private message Visit poster's website

Display posts from previous:  

All times are GMT + 1 Hour
Page 3 of 100
Goto page Previous  1, 2, 3, 4 ... 98, 99, 100  Next

Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum