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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Panasonic SA-HT900 ...
Has anybody got a proper paper service manual for this home cinema unit, or
access to a better Panasonic on-line copy for it, or a similar model for their part of the world, than I have got here in the UK ? The tray timing is completely screwed on the one I have on the bench. It looks like someone has been 'at it' before me. The copy of the manual on the UK Panasonic service website, is about two points to the left of useless in terms of the reassembly / timing procedures. It is not a zoomable pdf file, but one of those dreadful html things, where the photos and diagrams are all gifs with a resolution of about 20 x 10 ! They appear on the screen the size of a postage stamp - literally ... They are totally unreadable, and no use at all. It's not as if this is a cheapo unit. How on earth do they expect people to be able to fix the stuff, when this is the sort of level of support that they're providing to their service network ? Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. TIA Arfa |
#2
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Panasonic SA-HT900 ...
Arfa Daily wrote:
Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. Any obvious "timing holes" in the gear(s) that can give a clue? |
#3
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Panasonic SA-HT900 ...
On Wed, 03 Nov 2010 17:19:14 +0000, Arfa Daily wrote:
Has anybody got a proper paper service manual for this home cinema unit, or access to a better Panasonic on-line copy for it, or a similar model for their part of the world, than I have got here in the UK ? The tray timing is completely screwed on the one I have on the bench. It looks like someone has been 'at it' before me. The copy of the manual on the UK Panasonic service website, is about two points to the left of useless in terms of the reassembly / timing procedures. It is not a zoomable pdf file, but one of those dreadful html things, where the photos and diagrams are all gifs with a resolution of about 20 x 10 ! They appear on the screen the size of a postage stamp - literally ... They are totally unreadable, and no use at all. It's not as if this is a cheapo unit. How on earth do they expect people to be able to fix the stuff, when this is the sort of level of support that they're providing to their service network ? Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. TIA Arfa Don't have any info. But having worked on a similar 5 disc rotary changer unit I wanted to wish you good luck if you couldn't find suitable technical literature. -- Live Fast, Die Young and Leave a Pretty Corpse |
#4
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Panasonic SA-HT900 ...
Arfa Daily wrote:
Has anybody got a proper paper service manual for this home cinema unit, or access to a better Panasonic on-line copy for it, or a similar model for their part of the world, than I have got here in the UK ? The tray timing is completely screwed on the one I have on the bench. It looks like someone has been 'at it' before me. The copy of the manual on the UK Panasonic service website, is about two points to the left of useless in terms of the reassembly / timing procedures. It is not a zoomable pdf file, but one of those dreadful html things, where the photos and diagrams are all gifs with a resolution of about 20 x 10 ! They appear on the screen the size of a postage stamp - literally ... They are totally unreadable, and no use at all. It's not as if this is a cheapo unit. How on earth do they expect people to be able to fix the stuff, when this is the sort of level of support that they're providing to their service network ? Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. **Send me an email. I may be able to assist. -- Trevor Wilson www.rageaudio.com.au |
#5
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Panasonic SA-HT900 ...
"Trevor Wilson" wrote in message ... Arfa Daily wrote: Has anybody got a proper paper service manual for this home cinema unit, or access to a better Panasonic on-line copy for it, or a similar model for their part of the world, than I have got here in the UK ? The tray timing is completely screwed on the one I have on the bench. It looks like someone has been 'at it' before me. The copy of the manual on the UK Panasonic service website, is about two points to the left of useless in terms of the reassembly / timing procedures. It is not a zoomable pdf file, but one of those dreadful html things, where the photos and diagrams are all gifs with a resolution of about 20 x 10 ! They appear on the screen the size of a postage stamp - literally ... They are totally unreadable, and no use at all. It's not as if this is a cheapo unit. How on earth do they expect people to be able to fix the stuff, when this is the sort of level of support that they're providing to their service network ? Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. **Send me an email. I may be able to assist. -- Trevor Wilson www.rageaudio.com.au Thanks Trev. See direct reply to the mail you sent me. Arfa |
#6
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Panasonic SA-HT900 ...
"D Yuniskis" wrote in message ... Arfa Daily wrote: Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. Any obvious "timing holes" in the gear(s) that can give a clue? You would have thought so, wouldn't you ? The simple answer is "yes", there are two holes in the main cam gear. Follow this though, with "no" - they don't seem to give any clue as to where they should be set, and when ... :-( Actually, I now know what should be where, as Trevor in Oz has sent me a Panasonic publication (that I didn't see or - maybe spot - on the Pan UK website) that has a lot of general info on SA-HT series units, and down in the depths of it, is a single sheet line drawing of what should be where and when, together with some simple and straightforward notes. So tomorrow morning, I will give it a go. Here's hoping ... !! Arfa |
#7
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Panasonic SA-HT900 ...
"Meat Plow" wrote in message news On Wed, 03 Nov 2010 17:19:14 +0000, Arfa Daily wrote: Has anybody got a proper paper service manual for this home cinema unit, or access to a better Panasonic on-line copy for it, or a similar model for their part of the world, than I have got here in the UK ? The tray timing is completely screwed on the one I have on the bench. It looks like someone has been 'at it' before me. The copy of the manual on the UK Panasonic service website, is about two points to the left of useless in terms of the reassembly / timing procedures. It is not a zoomable pdf file, but one of those dreadful html things, where the photos and diagrams are all gifs with a resolution of about 20 x 10 ! They appear on the screen the size of a postage stamp - literally ... They are totally unreadable, and no use at all. It's not as if this is a cheapo unit. How on earth do they expect people to be able to fix the stuff, when this is the sort of level of support that they're providing to their service network ? Anyways, ranting aside, I just need to get a look at the tray re-assembly diagrams and any notes, especially in regard of relative positionings, and starting points for the cam gear, and the tray drive gear that runs off it. TIA Arfa Don't have any info. But having worked on a similar 5 disc rotary changer unit I wanted to wish you good luck if you couldn't find suitable technical literature. Think I've got what I need now, Meat - see my other reply in the thread. Thanks for your luck wishes ! Arfa |
#8
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And it all turned out ok ... :-)
Well, as it turned out, with the help of the info that Trev sent me, it was actually staggeringly simple to realign. Of course, nothing's that straightforward, is it ? After the tray was refitted and moving correctly when hand cranked from underneath via the little gear that they kindly give you to do just this, I put it back on power. The laser homed, the display said "TRAY INIT", and that's as far as it went, before spitting the tray out, coming to a stop, and the display changing to "TRAY OPEN". Nothing then worked at all, until it was powered back off. Looking at the area of the main PCB where the SMPS section is, there were several areas that were quite badly scorched, and numerous small(ish) electrolytics were located in these areas. A quick run over them with an ESR meter revealed four of them to be virtually open, so I figured that we may have dirty rails here, that were causing the micro to screw up during initialisation of the mechanics. Once the board was out, it was easy to see why it was discoloured. Panasonic, in a breathtakingly stupid bit of design work, have sited a whole bunch of sm regulator devices on the underside of this SRBP board, using the copper as a heatsink as well as an anchoring point. And then sited all the device decoupling caps immediately above. I mean, who designs this stuff in the first place, and then, what on earth is their manager thinking of, when he / she signs it off as an approved design ? Anyway, I replaced the caps and reassembled. Result ? Nothing, of course. Exactly the same ... :-/ It then occurred to me that at no time had I ever seen the carousel rotating, so I removed the tray again - confident now that I could put it back in a flash - to have a look underneath at the drive motor and sensors. This little bit of circuitry is connected back to the main PCB underneath the deck, via a white flexiprint - the type with the blue strengtheners at either end. When I looked a bit closer, at the board end, it was very sharply bent at the inner edge of the strengthener. A quick ohms check revealed that several of the ribbons were fractured at this point of bend. I had a suitable length replacement for it in the junkbox, but it still didn't quite end there. The original was one of those rather more rare types, where the exposed connection 'fingers' at either end, were on opposite sides of the ribbon, rather than both on the same side, as is more common, and was the way my proposed replacement was. Fortunately, it was long enough to be able to cut off the fingers at one end, and then scrape back on the opposite side to reveal a new set. The strengthener was then glued back to the ribbon, and the whole shebang refitted. This time, everything cycled correctly at power up, and each of the five disc positions was checked for the presence of a disc, before it all came to rest showing "NO DISC" in the display. It then opened ok, closed ok, and played a disc as it should. Nice to get to the bottom of one that looked like it might be a non starter at first :-) Arfa |
#9
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And it all turned out ok ... :-)
"Arfa Daily" wrote in message ... Well, as it turned out, with the help of the info that Trev sent me, it was actually staggeringly simple to realign. Of course, nothing's that straightforward, is it ? After the tray was refitted and moving correctly when hand cranked from underneath via the little gear that they kindly give you to do just this, I put it back on power. The laser homed, the display said "TRAY INIT", and that's as far as it went, before spitting the tray out, coming to a stop, and the display changing to "TRAY OPEN". Nothing then worked at all, until it was powered back off. Looking at the area of the main PCB where the SMPS section is, there were several areas that were quite badly scorched, and numerous small(ish) electrolytics were located in these areas. A quick run over them with an ESR meter revealed four of them to be virtually open, **Good one Arfa. Your post reminded me of a job that came in a couple of weeks ago. The client had left the item with a competitor, who made her pay for a new output IC and a service manual (all at full retail, of course). The company went belly-up before they could complete the repair, so they handed the item back to my client. She brought it 'round and I did a few tests on it. Everything pointed to a new output IC (why order a service manual?), so I replaced it. No change. 7 small electros later and the thing was performing nicely. Damned things. I don't even bother testing them anymore. At 13c each, I just replace them. -- Trevor Wilson www.rageaudio.com.au |
#10
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And it all turned out ok ... :-)
"Arfa Daily" wrote in message
... Well, as it turned out, with the help of the info that Trev sent me, it was actually staggeringly simple to realign. Of course, nothing's that straightforward, is it ? After the tray was refitted and moving correctly when hand cranked from underneath via the little gear that they kindly give you to do just this, I put it back on power. The laser homed, the display said "TRAY INIT", and that's as far as it went, before spitting the tray out, coming to a stop, and the display changing to "TRAY OPEN". Nothing then worked at all, until it was powered back off. Looking at the area of the main PCB where the SMPS section is, there were several areas that were quite badly scorched, and numerous small(ish) electrolytics were located in these areas. A quick run over them with an ESR meter revealed four of them to be virtually open, so I figured that we may have dirty rails here, that were causing the micro to screw up during initialisation of the mechanics. Once the board was out, it was easy to see why it was discoloured. Panasonic, in a breathtakingly stupid bit of design work, have sited a whole bunch of sm regulator devices on the underside of this SRBP board, using the copper as a heatsink as well as an anchoring point. And then sited all the device decoupling caps immediately above. I mean, who designs this stuff in the first place, and then, what on earth is their manager thinking of, when he / she signs it off as an approved design ? Anyway, I replaced the caps and reassembled. Result ? Nothing, of course. Exactly the same ... :-/ It then occurred to me that at no time had I ever seen the carousel rotating, so I removed the tray again - confident now that I could put it back in a flash - to have a look underneath at the drive motor and sensors. This little bit of circuitry is connected back to the main PCB underneath the deck, via a white flexiprint - the type with the blue strengtheners at either end. When I looked a bit closer, at the board end, it was very sharply bent at the inner edge of the strengthener. A quick ohms check revealed that several of the ribbons were fractured at this point of bend. I had a suitable length replacement for it in the junkbox, but it still didn't quite end there. The original was one of those rather more rare types, where the exposed connection 'fingers' at either end, were on opposite sides of the ribbon, rather than both on the same side, as is more common, and was the way my proposed replacement was. Fortunately, it was long enough to be able to cut off the fingers at one end, and then scrape back on the opposite side to reveal a new set. The strengthener was then glued back to the ribbon, and the whole shebang refitted. This time, everything cycled correctly at power up, and each of the five disc positions was checked for the presence of a disc, before it all came to rest showing "NO DISC" in the display. It then opened ok, closed ok, and played a disc as it should. Nice to get to the bottom of one that looked like it might be a non starter at first :-) Arfa As Trevor said, "Good one, Arfa" It does happen sometimes that the deeper we dig into something, we do prevail, even if at first it looks like a non-starter. Talk to you later. Mark Z. |
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