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The 9200 --:-- clock problem. |
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#76 |
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Join Date: Jun 2006
Posts: 34
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My 4 year old machine started showing the odd occasional manifestation of this problem around 2 years ago now which probably explains some missed recordings over that time. I guess the conformal coating is becoming conductive before visual signs of breakdown appear. At least, tanks to your work, Les we know whats going on here!
Vic |
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#77 |
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Forum Member
Join Date: Nov 2007
Posts: 2,669
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Quote:
My 4 year old machine started showing the odd occasional manifestation of this problem around 2 years ago now which probably explains some missed recordings over that time. I guess the conformal coating is becoming conductive before visual signs of breakdown appear. At least, tanks to your work, Les we know whats going on here!
Vic Whatever the reason for the contaminant we'll never know but at least it has made the repair very easy for the general public with no electronics skills required at all other than being solo on a screwdriver. My own board being two and a half years old doesn't show any symptoms whatsoever so it may be that Humax changed board supplier after a couple of years of 9200 manufacture and only older 9200s are likely to be affected. |
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#78 |
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Join Date: Jul 2010
Posts: 1
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Just joined up to say THANKS to Big-les
My 9200 is working properly again with just an eggcup of isopropyl and a dozen cotton buds ![]() Genius - thanks again. |
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#79 |
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Join Date: Nov 2007
Posts: 2,669
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Quote:
Just joined up to say THANKS to Big-les
My 9200 is working properly again with just an eggcup of isopropyl and a dozen cotton buds ![]() Genius - thanks again. |
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#80 |
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Join Date: May 2005
Location: wisbech, cambs / norfolk
Posts: 3,834
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Quote:
My guess is that the crystal and the super capacitor were installed in a separate process after the rest of the components...it may be that Humax changed board supplier after a couple of years....
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#81 |
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Join Date: Nov 2007
Posts: 2,669
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Or the process refined to fit all components in one step??
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#82 |
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Forum Member
Join Date: Jun 2006
Posts: 34
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This http://www.conformalcoating.co.uk/do...tin_Dec_08.pdf looks like the exact problem in the photographs of my board.
This possibly validates the fingerprints suspicion! Looks like generally the display/RTC boards have not been manufactured under an effective process. Some could say it's a perfect process as the boards generally last for the duration of the warranty period! Has anyone looked under the main PCB of the 9200? Vic |
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#83 |
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Join Date: Nov 2007
Posts: 2,669
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Quote:
.....
Looks like generally the display/RTC boards have not been manufactured under an effective process. Some could say it's a perfect process as the boards generally last for the duration of the warranty period! ..... |
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#84 |
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Join Date: Jun 2006
Posts: 34
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Quote:
the coating looked perfect on the two boards I looked at once the contamination was removed.
And so it did with mine! Vic |
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#85 |
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Join Date: Jul 2007
Posts: 643
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what a easy fix that was, thanks a lot big Les. Might look into getting a bigger hard drive now as well, now that I have seen how easy it looks to change
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#86 |
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Forum Member
Join Date: Sep 2007
Location: Birmingham, England
Posts: 65
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Managed to pluck up the courage to give this smart solution a go but sadly it didn't work for me.
At least I didn't bugger anything else up and it still 'works'! I realise it might take another attempt and I am willing to try again. Could I ask, for next time, can I test the clock without having to re-connect the hard drive? One other thought, in cleaning the Display Panel's PCB I noticed what looked like rust around the 'rechargeable battery' (CE921) component. How likely is it that this is the cause of the problem for me? Can I get hold of a replacement one of these? I partly ask because I've noticed recently (before doing today's clean-up) a deterioration of my clock problem - The clock has been flashing off and on (between the time and - - : - -) even when its switched on (i.e not on standby). Does this suggest another cause of the problem? |
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#87 |
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Forum Member
Join Date: Sep 2003
Location: East Coast of Lincolnshire
Posts: 318
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Quote:
Managed to pluck up the courage to give this smart solution a go but sadly it didn't work for me.
At least I didn't bugger anything else up and it still 'works'! I realise it might take another attempt and I am willing to try again. Could I ask, for next time, can I test the clock without having to re-connect the hard drive? One other thought, in cleaning the Display Panel's PCB I noticed what looked like rust around the 'rechargeable battery' (CE921) component. How likely is it that this is the cause of the problem for me? Can I get hold of a replacement one of these? I partly ask because I've noticed recently (before doing today's clean-up) a deterioration of my clock problem - The clock has been flashing off and on (between the time and - - : - -) even when its switched on (i.e not on standby). Does this suggest another cause of the problem? I am possibly in the minority by being of the opinion that the 'Super-Capacitor' is the cause of the contamination and as such I removed it completely. I fitted in its place a standard 10v 2200uF electrolytic. This will provide power for the clock for only a few seconds (or minutes at most) in the event of a power cut. The original would probably provide power for thirty minutes or more. I found that vigorous cleaning alone did not cure my clock, but that moving the crystal and soldering it directly to the pins of the clock IC then cutting the through board links that connect to the original solder pads for the crystal did work. It may be that the contamination had permeated through the links and into the pcb itself, either way this has worked for just over a month now. I have to say that without Big-Les finding the cause of failure I would still be contemplating making a small pcb to carry a clock IC, crystal and capacitor to then connect to the IC2 bus in replacement of the original components. Thanks Big-Les. |
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#88 |
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Forum Member
Join Date: Nov 2007
Posts: 2,669
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Quote:
.....
I am possibly in the minority by being of the opinion that the 'Super-Capacitor' is the cause of the contamination and as such I removed it completely. I fitted in its place a standard 10v 2200uF electrolytic. This will provide power for the clock for only a few seconds (or minutes at most) in the event of a power cut. The original would probably provide power for thirty minutes or more. I found that vigorous cleaning alone did not cure my clock, but that moving the crystal and soldering it directly to the pins of the clock IC then cutting the through board links that connect to the original solder pads for the crystal did work. It may be that the contamination had permeated through the links and into the pcb itself, either way this has worked for just over a month now. ..... I have seen the gunge around the top of the super capacitor but it is an almost solid substance which couldn't possibly flow onto the board, particularly with the vertical orientation of the board, so I'm afraid I can't agree with you. I admire your ingenuity in fitting a standard capacitor in place of the super capacitor but I wouldn't recommend anyone doing this as a cure. The super capacitor on Martin's board was not as good as a new one, had the gunge around the top, but it was still more than adequate for the job maintaining the time for many days. If anyone wants to replace the super capacitor then this is the one you need, but remember this will not cure the --:-- clock problem. |
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#89 |
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Forum Member
Join Date: Nov 2007
Posts: 2,669
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Quote:
.....
One other thought, in cleaning the Display Panel's PCB I noticed what looked like rust around the 'rechargeable battery' (CE921) component. How likely is it that this is the cause of the problem for me? Can I get hold of a replacement one of these? I partly ask because I've noticed recently (before doing today's clean-up) a deterioration of my clock problem - The clock has been flashing off and on (between the time and - - : - -) even when its switched on (i.e not on standby). Does this suggest another cause of the problem? I don't like the sound of your clock showing --:-- when switched ON, this may point to something more serious in your case. Even with the clock stopped (faulty clock board) the Hummy should show the correct time when switched ON and receiving a signal. When not receiving a signal (aerial out) the Hummy will show 13:00 when switched ON and count time from then. |
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#90 |
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Join Date: Feb 2006
Posts: 3,118
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Quote:
I don't like the sound of your clock showing --:-- when switched ON, this may point to something more serious in your case. Even with the clock stopped (faulty clock board) the Hummy should show the correct time when switched ON and receiving a signal.
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#91 |
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Join Date: Nov 2007
Posts: 2,669
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Quote:
I think this behaviour (clock flashing on and off when active)has been reported several times. We saw it at the same time as the clock in standby became erratic ( sometimes displayed, sometimes failed) and the behaviour stopped when the clock in standby failed permanently and didn't return when the clock board was changed. I think the two problems are linked.
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#92 |
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Forum Member
Join Date: Sep 2007
Location: Birmingham, England
Posts: 65
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Thanks for the feedback everyone. Quote:
It certainly is possible to test the clock without the HDD fitted. The 9200 will simply believe it is an earlier unit (similar to the F2-Fox-T) with no PVR facility.
I found that vigorous cleaning alone did not cure my clock, but that moving the crystal and soldering it directly to the pins of the clock IC then cutting the through board links that connect to the original solder pads for the crystal did work. |
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#93 |
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Forum Member
Join Date: Sep 2007
Location: Birmingham, England
Posts: 65
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Quote:
I think this behaviour (clock flashing on and off when active)has been reported several times. We saw it at the same time as the clock in standby became erratic ( sometimes displayed, sometimes failed) and the behaviour stopped when the clock in standby failed permanently and didn't return when the clock board was changed. I think the two problems are linked.
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#94 |
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Forum Member
Join Date: Sep 2007
Location: Birmingham, England
Posts: 65
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Quote:
Thanks for that Martin, so maybe gdh82 simply hasn't cleaned the board well enough.
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#95 |
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Join Date: Sep 2003
Location: East Coast of Lincolnshire
Posts: 318
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Quote:
Over a week actually, I mentioned this in the second paragraph of my instructional post.
Despite reading your initial instructional post, I hadn't noticed that. I apologise for not taking more notes. Quote:
I have seen the gunge around the top of the super capacitor but it is an almost solid substance which couldn't possibly flow onto the board, particularly with the vertical orientation of the board, so I'm afraid I can't agree with you.
I know you've done a lot of work in this area, and I know you've done a lot of tests in the clock circuitry, and I don't want you to think I don't appreciate your generosity in sharing your cure, as I do. I'll say again: Thanks for all your work in locating the area of the failure. It could be that my long held prejudice against electrolytics is holding me back... But I'll personally sleep better for knowing it is no longer going to cause me problems. |
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#96 |
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Join Date: Nov 2007
Posts: 2,669
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I was going to say 'days', but didn't want to over-egg the capabilities of the 'Super-Capacitor'!
Despite reading your initial instructional post, I hadn't noticed that. I apologise for not taking more notes. I know that very few other people agree with me and I don't want to start a discussion that I don't have the educational clout to backup - but... Over 25 years of repairing consumer electronics equipment has given me a deep distrust of any electrolytic capacitor showing any signs of distress. These can and often do measure very well on both capacitance meters and E.S.R. (Equivalent Series Resistance) meters despite clear signs of leakage. The electrolyte can be very corrosive (corroding copper circuit tracks completely in extremely short periods of time) and can penetrate deep into soldered joints by capillary action, spreading across large areas remarkably quickly. It was not unusual to find that the initial reported failure of an item of equipment was actually the secondary cause of failure, the initial cause being a leaky capacitor which on its own produced no symptoms. Had that capacitor not been replaced, some other failure would have occurred eventually which would be expected to be covered under our repair warranty. Much cheaper to replace the electrolytic capacitor in the first place and be sure of a lasting repair. I know you've done a lot of work in this area, and I know you've done a lot of tests in the clock circuitry, and I don't want you to think I don't appreciate your generosity in sharing your cure, as I do. I'll say again: Thanks for all your work in locating the area of the failure. It could be that my long held prejudice against electrolytics is holding me back... But I'll personally sleep better for knowing it is no longer going to cause me problems. From the measures you had to go to to get your clock going I would say that your board was in a very much worse condition than the two boards I fixed. |
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#97 |
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Join Date: Nov 2007
Posts: 2,669
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I'm hoping so too. I'll give it another bash soon and post my results...
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#98 |
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Forum Member
Join Date: Sep 2007
Location: Birmingham, England
Posts: 65
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Quote:
What cleaning agent are you using?
For next time, I imagine I'll need to re-insert the aerial lead (to provide time information) when I come to test. Is that right? Or should it display 00:00 if its fixed? Thanks again. |
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#99 |
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Join Date: May 2008
Posts: 15
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To add my twopennys worth. I cleaned my board, a few weeks ago, with Sergical Spirit.
Did not work even though I gave it a very thorough clean, including the gunge around the capacitor. Have finally got it stripped again and gave it an even more thorough cleaning and hay presto, all works fine. I think all you need is patience. Keep cleaning and it will work.?? |
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#100 |
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Forum Member
Join Date: Nov 2007
Posts: 2,669
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Quote:
To add my twopennys worth. I cleaned my board, a few weeks ago, with Sergical Spirit.
Did not work even though I gave it a very thorough clean, including the gunge around the capacitor. Have finally got it stripped again and gave it an even more thorough cleaning and hay presto, all works fine. I think all you need is patience. Keep cleaning and it will work.?? Quote form my instructional post. Quote:
The success of this repair will depend on how thoroughly you do the cleaning.
..... I could see with my lab equipment that the oscillations were getting stronger with each cleaning process. |
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At least I didn't bugger anything else up and it still 'works'!