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newcoppiceman
Joined: 15 Jun 2009
Posts: 13
Location: Woking, Surrey UK
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 Posted: Sun Aug 16, 2009 2:53 am Post subject: Goodmans GHD1621F2 GHD2521F2 PVR Hard Drive Fault (Ticking) |
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Just fixed my uncle's GHD1621F2. Symptoms were that it 'couldn't find' the hard drive - the system details page had no entry for it and was showing '0GB'; an ear to the hard drive revealed a ticking noise. Before complete failure, over a couple of weeks the hard drive had been taking a while to appear to the system.
The 12V supply to the hard drive appeared to measure ok once the power connector had been unplugged from the latter, but was incapable of supplying any meaningful current; I tried resistors in the range 22-150R as a dummy load, but the volts collapsed to zero each time.
As the 5V supply was good (the rest of the PVR worked ok) this could only mean the failure of a component at the 'back-end' of the switched-mode power supply (SMPS) board. Sure enough, visual inspection revealed E7 (yes, that's an E) had oozed its contents. It's a 1000uF/16V capacitor but measured only about 500uF. The 'oozing' wasn't that apparent due to the use of dabs of glue to secure this and similar components to the board. Significant that E7 is right next to a heat sink so had been gently baking. A 105 degree rated component had been used in manufacture (rather than the traditional 85 degree type) but this didn't save it.
I replaced E7 and glued in place a mica 'screen' (from bits salvaged from an old toaster - not shown in photo) to try to keep the heat off the new component.
[img]http://www.flickr.com/photos/38818955@N07/3824388173/[/img]
[img]http://www.flickr.com/photos/38818955@N07/3825190138/[/img]
[img]http://www.flickr.com/photos/38818955@N07/3825190842/[/img]
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vtech
Joined: 08 May 2006
Posts: 1264
Location: USA
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| Posted: Sun Aug 16, 2009 5:32 am Post subject: |
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Excellent use of common troubleshooting method. Insufficient filteration will always result in DC level to buckle under load. This is where scoping the DC line can also be used to reveal the ripple.
ps; fixed your links for the pix to show |
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newcoppiceman
Joined: 15 Jun 2009
Posts: 13
Location: Woking, Surrey UK
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| Posted: Sun Aug 16, 2009 8:00 am Post subject: Thanks... |
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...for fixing the links! First time I'd tried including photos (not sure what went wrong  ).
Yes, getting the scope out was the next step. This is a good example of where DMMs can be misleading - the scope would soon have shown that all wasn't well with the 12V rail. |
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vtech
Joined: 08 May 2006
Posts: 1264
Location: USA
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| Posted: Sun Aug 16, 2009 2:39 pm Post subject: Re: Thanks... |
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| newcoppiceman wrote: | | ...for fixing the links! First time I'd tried including photos (not sure what went wrong ). |
The img tag only works when the exact location of the picture is specified--not the general html address used for viewing it.
In other word, the address used within the IMG tag MUST end with .jpg rather than html |
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bevray
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| Posted: Sat Jan 23, 2010 7:19 pm Post subject: |
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Exactly the same symptoms, replaced the capacitor for 42p, job done, all recordings recovered  |
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bevray
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| Posted: Sat Jan 23, 2010 7:24 pm Post subject: |
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| Forgot to say thanks very much to all, saved me an expensive replacement. Isn't the internet great |
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Guest
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| Posted: Sun Nov 14, 2010 4:53 pm Post subject: Re: Goodmans GHD1621F2 GHD2521F2 PVR Hard Drive Fault (Ticki |
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| I have exactly the same problem with my hdd. So what do i need to buy snd insert to fix it? I have a catalog with alot of different kinds and im not fimiliar with them can u help please? |
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