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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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Mitsubishi VS 4507R
Just got a used VS4507R with the following issues:
Power relay acts funny, have to push the on button repeatedly to start TV Objects on the screen appear to have a 'halo' on the top right. Also if someone has any idea how to get the service manual. Thanks |
#2
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Yes I ordered that service manual from treasure chest corp. www.servicemanuals.net and they were excellent. You might want to look at the AC board you can't miss it the AC line cord goes to it and check over the large wattage resistors see if they didn't loosen and check D951 it looks like a 12v zener across the K900 relay also Q950 the relay drive transistor also see if the base is forward biased while the set is on. "peter" wrote in message ... Just got a used VS4507R with the following issues: Power relay acts funny, have to push the on button repeatedly to start TV Objects on the screen appear to have a 'halo' on the top right. Also if someone has any idea how to get the service manual. Thanks |
#3
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You might want to invest in about $40 in capacitors rather than the manual
at this point. This is a V11 chassis set. We repair them all the time and fix 90+% of them just by replacing the leaky capacitors, repairing corrosion damage from the electrolyte, and repairing heat damaged solder connections. Google the chassis number for specific suggestions on how to find the bad caps. Leonard "peter" wrote in message ... Just got a used VS4507R with the following issues: Power relay acts funny, have to push the on button repeatedly to start TV Objects on the screen appear to have a 'halo' on the top right. Also if someone has any idea how to get the service manual. Thanks |
#4
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Having a hard time finding anything on the V11 chassis, any
suggestions on how to find the bad caps Thanx On Sat, 5 Feb 2005 19:44:02 -0500, "Leonard Caillouet" wrote: You might want to invest in about $40 in capacitors rather than the manual at this point. This is a V11 chassis set. We repair them all the time and fix 90+% of them just by replacing the leaky capacitors, repairing corrosion damage from the electrolyte, and repairing heat damaged solder connections. Google the chassis number for specific suggestions on how to find the bad caps. Leonard "peter" wrote in message .. . Just got a used VS4507R with the following issues: Power relay acts funny, have to push the on button repeatedly to start TV Objects on the screen appear to have a 'halo' on the top right. Also if someone has any idea how to get the service manual. Thanks |
#5
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Bad caps can be found by using a ESR Meter .
kip "peter" wrote in message ... Having a hard time finding anything on the V11 chassis, any suggestions on how to find the bad caps Thanx On Sat, 5 Feb 2005 19:44:02 -0500, "Leonard Caillouet" wrote: You might want to invest in about $40 in capacitors rather than the manual at this point. This is a V11 chassis set. We repair them all the time and fix 90+% of them just by replacing the leaky capacitors, repairing corrosion damage from the electrolyte, and repairing heat damaged solder connections. Google the chassis number for specific suggestions on how to find the bad caps. Leonard "peter" wrote in message . .. Just got a used VS4507R with the following issues: Power relay acts funny, have to push the on button repeatedly to start TV Objects on the screen appear to have a 'halo' on the top right. Also if someone has any idea how to get the service manual. Thanks |
#6
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"kip" wrote in message .. . Bad caps can be found by using a ESR Meter . Some can, some cannot. I just did one a few weeks ago in which we changed 112 caps. Just for curiosity, I checked a handful of the ones that we pulled for obvious electrolyte leakage and found nearly all of them had good ESR. A few of them had low capacitance. Still more of them had high DA and DC leakage. Still the vast majority were just leaking electrolyte. Our procedure for these sets is: 1. Test the tubes. If they have low emission and restoration is ineffective don't bother to fix the rest. Don't forget to look at the phosphors. 2. Look for black legs on the caps (negative leg mostly), black corrosion on the traces around the cap. Pull the bad caps. 3. Resolder the remaining caps, listen for sizzle and smell for the fishy smell. Pull the bad ones. 4. Test the rest of the caps. Pull the bad ones. 5. Scrape the black goo from the traces and tin them with solder, repair any discontinuities. 6. Repair heat damaged solder joints. 7. Now you can troubleshoot the set if the problems are not all fixed. The steps above fix at least 90% of them. While the problems with the leaky caps seem to be worse in the South, where we are, we have not found one of these sets with less than 100 bad caps in the last couple of years. You may find less in cooler areas, but there surely will be some. Also, since these sets are nearly 15 years old, the condition of the tubes is always suspect. We still see a lot of them that look and test good, but it is certainly not worth the time and cost to rebuild one with weak tubes. Typically, the V11 chassis is the worst, with over 100 bad caps at this age. The V12 is next with 30-60 bad caps typical. The V10 chassis typically has a few less than the V12, even though it is older. Tubes are more likely shot on these. We charge $390 (P&L, new caps, pulls for other parts, new parts used if available for additional cost) in the shop or $490 in the field locally(pull the boards for shop rebuild) on these sets, flat rate, if the tubes test OK. Most shops could not afford to do them for that rate profitably and likely charge more. We some old parts for these for pulls if we need parts and try to keep a set of rebuilt boards around. Leonard |
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