V10 chassis. Capacitors. We have found that on the Mitsubishi V10, V11, and V12 chassis and related variants it is pointless to service the sets without carefully going over the electrolytic capacitors on all of the major boards. We typically find at least 2 dozen leaky or high ESR capacitors on the V10 and V12 sets and at least 60 on the V11 (my record is 146). Similarly on the direct view chassis WA, UM2 and RA variants expect a couple of dozen bad caps. Most of the leaky caps are Rubycon and Nichicon polar electroytics with black labels. Earlier Mitsubishi chassis rarely have many leaky caps, more likely normally aged ones like you would expect in any set. Later chassis may have a few leaky caps in the power supply and audio circuits and PIP modules, but not to the extent of these. Our procedure goes like this: 0) Test the CRTs. If they are bad or have any scored phosphors, NWR. Prepare the customer for a big repair bill. 1) Look for spots around caps. 2) Look for black on the negative legs. 3) Look for black on the traces at the negative legs, as well as gray powdery looking solder. 4) Resolder the caps that do not visually indicate electrolyte leakage, listen and smell. Leaky caps will often sizzle and will always smell like bad fish. 5) After screening the caps for electrolyte leakage and removing the bad ones, ESR the remaining caps. 6) Scrape all of the black corrosion off of the traces and tin the exposed copper, wash the board in alcohol, replace the caps, repair weak solder joints at heat producing parts. 7) Now you can start troubleshooting, but the vast majority of problems have just been fixed, including nearly all of the "gremlins". Expect it to take about an hour and a half per board unless you do a lot of them. We have it down to an average of 45 minutes per board but we go through a few of these. Many of the caps leaking electrolyte will test good otherwise. Often the electrolyte itself, or the corrosion that it causes is the problem. I have found that relatively few caps will have bad ESR other than those in the power supply and vertical output stages. Replacing the small electrolytics in the power supply and vert output areas and getting all of the ones leaking electrolyte almost always solves the problems with these sets. If there are other problems you will likely chase your tail if you don't do the caps before troubleshooting. Leonard Caillouet Electronics World Gainesville, FL ----- Original Message ----- From: "Paul" <dntwntv@xxxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Friday, February 13, 2004 6:28 PM Subject: [TechAssist] Re: Mitsubishi V6015R Proj TV (correction) > Model is VS 6015R > Paul <dntwntv@xxxxxxxxxxxxx> wrote:This set is infested with gremlins. Original problem in the customers house was no snd. no picture. Has had every symptom from no start, to no filament, to picture tubes light but not tuner no sound. Checked the power supply has 130v for the horiz. and 28v and 12v for the vertical I/C. Have replaced vertical I/C and lytics in vertical circuit. One was leaking thought that was the answer. Have replaced the HOT and rung the flyback xfmr. Have checked esr on lytics in the area of HV Xmr. Have re-soldered all the heat affected areas. I had the set running with sound and tuner working. Thought I had found everything. It shut down after about a minute or two. When I turned it back on it lasted for maybe 30. sec and the next time it was back to start and shut down. Checked I/C's on all the heat-sinks for excessive heat.Nothing abnormal. Could use some ideas or similar experiences. Paul > > Paul ,B Central TV&Video Grover Beach Ca. > > > -------------------------------------------------------------------------- --- > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ > > > Paul ,B Central TV&Video Grover Beach Ca. > > > -------------------------------------------------------------------------- --- > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ ----------------------------------------------------------------------------- Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/