|
Mitsubishi TV has a bad cap or two.....
Got this set in the other day, model CS-28EX1C. This is a 26" set from
'93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. One section, a plug-in module labeled PIP-C (picture-in-picture?), looks particularly daunting; it contains 19 SURFACE-MOUNT caps and EVERY ONE appears to be spilling electrolyte. I guess my question is this; should I even bother trying to replace all the surface-mount caps, or is that board not essential to the operation of the set? I suspect the problem with wavy edges may be caps in the comb filter, but I'm not certain. I told the customer that I may have to replace as many as 40 or 50 parts (caps) before the set could work reliably, needless to say he doesn't feel like putting that much money into it. Even if he lets me keep the set though, I'd still like to fix it for resale. One final question: the regulator unit (STR3130) has been replaced on two separate occasions. I know because I serviced the set both times, when it belonged to a previous owner. The last one held up for about 2 years before shorting. Could there be an underlying problem, or is it simply poor design? A 1-amp STR regulator seems a bit small for a 26" stereo set if you ask me..... Much thanks for any advice. |
Problem is you have just encountered a typical repair on these sets. Seen
too many with numerous failed or leaky electrolytics. Only fix is to replace the defecive caps, clean the debris from the boards while doing that process, and look closely for any damaged traces from the electrolyte. Can become a rather challenging task!! "Chris F." wrote in message ... Got this set in the other day, model CS-28EX1C. This is a 26" set from '93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. One section, a plug-in module labeled PIP-C (picture-in-picture?), looks particularly daunting; it contains 19 SURFACE-MOUNT caps and EVERY ONE appears to be spilling electrolyte. I guess my question is this; should I even bother trying to replace all the surface-mount caps, or is that board not essential to the operation of the set? I suspect the problem with wavy edges may be caps in the comb filter, but I'm not certain. I told the customer that I may have to replace as many as 40 or 50 parts (caps) before the set could work reliably, needless to say he doesn't feel like putting that much money into it. Even if he lets me keep the set though, I'd still like to fix it for resale. One final question: the regulator unit (STR3130) has been replaced on two separate occasions. I know because I serviced the set both times, when it belonged to a previous owner. The last one held up for about 2 years before shorting. Could there be an underlying problem, or is it simply poor design? A 1-amp STR regulator seems a bit small for a 26" stereo set if you ask me..... Much thanks for any advice. |
The regulator failure was due to not completing the whole repair the last
couple of times. Capacitor problems are the cause of the regulator failure. Do not forget to double check the regulator bypass resistor to see if it has increased in value or opened up. Welcome to the world of just about every Mitz set from that era, mass capacitor replacement is required for a proper long term repair. Most people are not willing to put the kind of money into the set for a good repair after 7 or so years. David |
"Chris F." wrote in message ... Got this set in the other day, model CS-28EX1C. This is a 26" set from '93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. One section, a plug-in module labeled PIP-C (picture-in-picture?), looks particularly daunting; it contains 19 SURFACE-MOUNT caps and EVERY ONE appears to be spilling electrolyte. I guess my question is this; should I even bother trying to replace all the surface-mount caps, or is that board not essential to the operation of the set? I suspect the problem with wavy edges may be caps in the comb filter, but I'm not certain. I told the customer that I may have to replace as many as 40 or 50 parts (caps) before the set could work reliably, needless to say he doesn't feel like putting that much money into it. Even if he lets me keep the set though, I'd still like to fix it for resale. One final question: the regulator unit (STR3130) has been replaced on two separate occasions. I know because I serviced the set both times, when it belonged to a previous owner. The last one held up for about 2 years before shorting. Could there be an underlying problem, or is it simply poor design? A 1-amp STR regulator seems a bit small for a 26" stereo set if you ask me..... Much thanks for any advice. Remove the pip board and put a 4.7ufd cap from pin 5 to 11 on the connector toward the rear of the set. That will bypass the video and the board will not be needed. |
On Sat, 28 Aug 2004 22:42:35 GMT, "Chris F."
put finger to keyboard and composed: Got this set in the other day, model CS-28EX1C. This is a 26" set from '93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. That's sad. I have a 20 year old Mitsubishi set that has never failed, and still has an excellent picture. What have Mitsubishi changed in their later models? What brand of caps are they using in your set? - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
That's sad. I have a 20 year old Mitsubishi set that has never failed,
and still has an excellent picture. What have Mitsubishi changed in their later models? What brand of caps are they using in your set? Mitsubishi had used Rubycon caps, which is actually a surprise. - Reinhart |
The Mitsubishi problems with leaky capacitors were mostly in the early 90s
and were polarized electrolytic radial mount caps supplied by Rubycon and Nichicon. Somewhat later there were also the infamous PIP modules with the surface mount caps that leaked, similar to the Sony sound modules used in many brands of sets. We still repair most of the larger sets when the CRTs are in good condition, but to get a reliable fix you have to inspect every cap for leakage and test for ESR. Most of the sets have been very reliable other than the capacitor problems. The big Mitsubishi CRTs in the direct view sets have been some of the most reliable in the long term that anyone ever supplied. Fixing a 27-28" Mitsubishi set with leaky caps is rarely going to make sense these days. These sets were nothing special, not bad, but typically not significantly better than other products of their day. Some of the CRTs were actually rather poor, unlike the very high quality of the larger ones and the RPTV tubes. Leonard "Franc Zabkar" wrote in message ... On Sat, 28 Aug 2004 22:42:35 GMT, "Chris F." put finger to keyboard and composed: Got this set in the other day, model CS-28EX1C. This is a 26" set from '93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. That's sad. I have a 20 year old Mitsubishi set that has never failed, and still has an excellent picture. What have Mitsubishi changed in their later models? What brand of caps are they using in your set? - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
It's strange, I see Rubycon and Nichicon caps in many other brands of sets,
but they only seem to (physically) leak in Mitsubishu TV's / VCR's. Maybe these were all part of one bad lot?? "Leonard Caillouet" wrote in message news:gQCYc.16693$bT1.784@fed1read07... The Mitsubishi problems with leaky capacitors were mostly in the early 90s and were polarized electrolytic radial mount caps supplied by Rubycon and Nichicon. Somewhat later there were also the infamous PIP modules with the surface mount caps that leaked, similar to the Sony sound modules used in many brands of sets. We still repair most of the larger sets when the CRTs are in good condition, but to get a reliable fix you have to inspect every cap for leakage and test for ESR. Most of the sets have been very reliable other than the capacitor problems. The big Mitsubishi CRTs in the direct view sets have been some of the most reliable in the long term that anyone ever supplied. Fixing a 27-28" Mitsubishi set with leaky caps is rarely going to make sense these days. These sets were nothing special, not bad, but typically not significantly better than other products of their day. Some of the CRTs were actually rather poor, unlike the very high quality of the larger ones and the RPTV tubes. Leonard "Franc Zabkar" wrote in message ... On Sat, 28 Aug 2004 22:42:35 GMT, "Chris F." put finger to keyboard and composed: Got this set in the other day, model CS-28EX1C. This is a 26" set from '93. It came in dead, and once I got it going (replaced the STR regulator) it was apparent there were other problems. There was some raster shrinkage at the top, and the whole picture - though very clear - has wavy edges - frills, I guess - on bright objects such as letters. Kind of like looking at your reflection on a ripply pond. As I started checking caps in the vertical output, it also became apparent that the set would not be an easy fix. Seems this is one of those infamous Mitsubishi's with the caps that leak not only internally, but physically as well. I replaced a bunch of these in the vertical output, that fixed the shrunk picture but that was it. It appears that almost EVERY SINGLE CAP IN THE SET has started to physically leak or at least gone up in ESR. That's sad. I have a 20 year old Mitsubishi set that has never failed, and still has an excellent picture. What have Mitsubishi changed in their later models? What brand of caps are they using in your set? - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
On Mon, 30 Aug 2004 05:08:56 -0400, "Leonard Caillouet"
put finger to keyboard and composed: The Mitsubishi problems with leaky capacitors were mostly in the early 90s and were polarized electrolytic radial mount caps supplied by Rubycon and Nichicon. Somewhat later there were also the infamous PIP modules with the surface mount caps that leaked, similar to the Sony sound modules used in many brands of sets. We still repair most of the larger sets when the CRTs are in good condition, but to get a reliable fix you have to inspect every cap for leakage and test for ESR. Most of the sets have been very reliable other than the capacitor problems. The big Mitsubishi CRTs in the direct view sets have been some of the most reliable in the long term that anyone ever supplied. Fixing a 27-28" Mitsubishi set with leaky caps is rarely going to make sense these days. These sets were nothing special, not bad, but typically not significantly better than other products of their day. Some of the CRTs were actually rather poor, unlike the very high quality of the larger ones and the RPTV tubes. Leonard I don't recall any consistently bad experiences with either Rubycon or Nichicon capacitors in any appliance. In any case, it seems strange that *both* brands of cap would cause problems for the one manufacturer. I'm not surprised about the smt caps, though. In Australia Mitsubishi TVs and VCRs were rebadged by AWA. I've only ever worked on the older TVs, but these invariably had excellent CRTs. I also don't recall ever having changed a Mitsubishi flyback transformer (except once in error). - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
My guess is that they were sold some counterfeits by some supplier.
Leonard "Franc Zabkar" wrote in message ... On Mon, 30 Aug 2004 05:08:56 -0400, "Leonard Caillouet" put finger to keyboard and composed: The Mitsubishi problems with leaky capacitors were mostly in the early 90s and were polarized electrolytic radial mount caps supplied by Rubycon and Nichicon. Somewhat later there were also the infamous PIP modules with the surface mount caps that leaked, similar to the Sony sound modules used in many brands of sets. We still repair most of the larger sets when the CRTs are in good condition, but to get a reliable fix you have to inspect every cap for leakage and test for ESR. Most of the sets have been very reliable other than the capacitor problems. The big Mitsubishi CRTs in the direct view sets have been some of the most reliable in the long term that anyone ever supplied. Fixing a 27-28" Mitsubishi set with leaky caps is rarely going to make sense these days. These sets were nothing special, not bad, but typically not significantly better than other products of their day. Some of the CRTs were actually rather poor, unlike the very high quality of the larger ones and the RPTV tubes. Leonard I don't recall any consistently bad experiences with either Rubycon or Nichicon capacitors in any appliance. In any case, it seems strange that *both* brands of cap would cause problems for the one manufacturer. I'm not surprised about the smt caps, though. In Australia Mitsubishi TVs and VCRs were rebadged by AWA. I've only ever worked on the older TVs, but these invariably had excellent CRTs. I also don't recall ever having changed a Mitsubishi flyback transformer (except once in error). - Franc Zabkar -- Please remove one 's' from my address when replying by email. |
| All times are GMT +1. The time now is 04:45 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter