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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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Toshiba TV CF3266a
My son's future father-in-law just gave him a Toshiba CF3266a set that had
been replaced. This old TV has been losing vertical amplitude and adjustments were no longer able to restore the size. I have not seen this set yet , but have been invited to try fixing it. My understanding is that picture shrink had been from both top and bottom. I am betting it is a cap or two that have degraded. This box is a 1991 build. Are there any particular suspects in the vertical amp section. I am also hoping that the suspects are PTH and not surface mounted. I have no way of checking caps other than a VOM to check for leakage and plain old substitution if I can find suitable replacements. I am well aware of HV concerns and will keep my fingers away from places that bite. Charlie |
#2
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Charlie Bress:
When you are not too busy filming CSI Las Vegas you should do a google groups archive search for "Toshiba vertical"..... you will find dozens of good hits that will most likely pinpoint the problem to dry, leaky, high ESR, or otherwise faulty electrolytics in the vertical deflection circuitry..... this has been a very frequent repair topic on this newsgroup for many years..... so there will be lots of archived posts to read and to learn from. Also you should go to the website for this newsgroup at http://www.repairfaq.org/ there with some searching you will find specific repair hints and important safety information so if you attempt to repair the television yourself you can avoid the dangerous and lethal electrical shock hazards.... note that these hazards can still be present even when the television is disconnected from the AC power.... be careful. If after reading through the repairfaq and other google archive information you are still not certain how to proceed then you should at the very least TAKE it to a repair shop for a repair cost estimate so you can make an intelligent repair decision with facts. This is usually NOT an expensive repair..... a set of this size may be worth the repair price as long as the CRT still has good emissions. -- Best Regards, Daniel Sofie Electronics Supply & Repair - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Charlie Bress" wrote in message ... My son's future father-in-law just gave him a Toshiba CF3266a set that had been replaced. This old TV has been losing vertical amplitude and adjustments were no longer able to restore the size. I have not seen this set yet , but have been invited to try fixing it. My understanding is that picture shrink had been from both top and bottom. I am betting it is a cap or two that have degraded. This box is a 1991 build. Are there any particular suspects in the vertical amp section. I am also hoping that the suspects are PTH and not surface mounted. I have no way of checking caps other than a VOM to check for leakage and plain old substitution if I can find suitable replacements. I am well aware of HV concerns and will keep my fingers away from places that bite. Charlie |
#3
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Thanks for the tips.
I had tried some searches that were not productive, but I hadn't tried Google groups. I have a fair amount of experience with TV repair and I am well aware of the shock hazards. My biggest problem is that I haven't had much need to do component level repair since everything went solid state. That dates me, but the basics stay the same. It is the implementations that have changed. Charlie "sofie" wrote in message ... Charlie Bress: When you are not too busy filming CSI Las Vegas you should do a google groups archive search for "Toshiba vertical"..... you will find dozens of good hits that will most likely pinpoint the problem to dry, leaky, high ESR, or otherwise faulty electrolytics in the vertical deflection circuitry..... this has been a very frequent repair topic on this newsgroup for many years..... so there will be lots of archived posts to read and to learn from. Also you should go to the website for this newsgroup at http://www.repairfaq.org/ there with some searching you will find specific repair hints and important safety information so if you attempt to repair the television yourself you can avoid the dangerous and lethal electrical shock hazards.... note that these hazards can still be present even when the television is disconnected from the AC power.... be careful. If after reading through the repairfaq and other google archive information you are still not certain how to proceed then you should at the very least TAKE it to a repair shop for a repair cost estimate so you can make an intelligent repair decision with facts. This is usually NOT an expensive repair..... a set of this size may be worth the repair price as long as the CRT still has good emissions. -- Best Regards, Daniel Sofie Electronics Supply & Repair - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Charlie Bress" wrote in message ... My son's future father-in-law just gave him a Toshiba CF3266a set that had been replaced. This old TV has been losing vertical amplitude and adjustments were no longer able to restore the size. I have not seen this set yet , but have been invited to try fixing it. My understanding is that picture shrink had been from both top and bottom. I am betting it is a cap or two that have degraded. This box is a 1991 build. Are there any particular suspects in the vertical amp section. I am also hoping that the suspects are PTH and not surface mounted. I have no way of checking caps other than a VOM to check for leakage and plain old substitution if I can find suitable replacements. I am well aware of HV concerns and will keep my fingers away from places that bite. Charlie |
#4
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Google Groups at sci.electronics.repair for "toshiba vertical" should
give you all the information. Many different models had the same problems with capacitors. Once you find the vertical output ic, the capacitors with the same numbers C308,c301, etc. Realize you won't be able to hit Radio Shack for suitable replacement parts as they need to be high temperature and preferably low esr, high precision capacitors. In that circuit if the small one 1uF or 2.2uf change value with temperature, you will definitely see a change in vertical size and linearity as the tv warms up. As long as the capacitors have not damaged the vertical ic (some deflection is still present to mostly full screen) then the capacitors should be the full fix. While you are in the tv there are some power supply capacitors that often go bad soon after the vertical ones. Google for Toshiba power supply capacitors. I think some of the locations were c840,c822,c841,c863 etc. Exact locations can vary by model a bit. |
#5
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Yea ! Right.
"Charlie Bress" wrote in message ... Thanks for the tips. I had tried some searches that were not productive, but I hadn't tried Google groups. I have a fair amount of experience with TV repair and I am well aware of the shock hazards. My biggest problem is that I haven't had much need to do component level repair since everything went solid state. That dates me, but the basics stay the same. It is the implementations that have changed. Charlie "sofie" wrote in message ... Charlie Bress: When you are not too busy filming CSI Las Vegas you should do a google groups archive search for "Toshiba vertical"..... you will find dozens of good hits that will most likely pinpoint the problem to dry, leaky, high ESR, or otherwise faulty electrolytics in the vertical deflection circuitry..... this has been a very frequent repair topic on this newsgroup for many years..... so there will be lots of archived posts to read and to learn from. Also you should go to the website for this newsgroup at http://www.repairfaq.org/ there with some searching you will find specific repair hints and important safety information so if you attempt to repair the television yourself you can avoid the dangerous and lethal electrical shock hazards.... note that these hazards can still be present even when the television is disconnected from the AC power.... be careful. If after reading through the repairfaq and other google archive information you are still not certain how to proceed then you should at the very least TAKE it to a repair shop for a repair cost estimate so you can make an intelligent repair decision with facts. This is usually NOT an expensive repair..... a set of this size may be worth the repair price as long as the CRT still has good emissions. -- Best Regards, Daniel Sofie Electronics Supply & Repair - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Charlie Bress" wrote in message ... My son's future father-in-law just gave him a Toshiba CF3266a set that had been replaced. This old TV has been losing vertical amplitude and adjustments were no longer able to restore the size. I have not seen this set yet , but have been invited to try fixing it. My understanding is that picture shrink had been from both top and bottom. I am betting it is a cap or two that have degraded. This box is a 1991 build. Are there any particular suspects in the vertical amp section. I am also hoping that the suspects are PTH and not surface mounted. I have no way of checking caps other than a VOM to check for leakage and plain old substitution if I can find suitable replacements. I am well aware of HV concerns and will keep my fingers away from places that bite. Charlie |
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