David;
What do you know about Pioneers, I got one that is frying just like the OP said. I've checked all the usuals, changed the opto cause you never can be sure. The problem is that this SMPS will not start if brought up slow on a variac, but this may be normal. No print. I am to the point of going in sideways, and if you don't know what I mean by that, here it is;
I am considering using substitute Hdrive from a Sencore analyst while bringing it up on a variac slowly, to check the entire feedback circuit. This is a PITA, I'll start another thread on it when I got the model and all that in front of me.
Now to the original poster;
I don't think it was too cool for you to put that whole email address in the subject line. He doesn't seem to be pissed so I don't care, just a word to the wise. Why ? at least make the spammers come in the group to harvest emails. In the subject line it is right in front of them. I hate it when an email address get screwed up.
OK, I do not understand why you replaced the convergence PS. The set will run without it and you will get a picture. You might do well at service, but let me tell you, when they start considering your billable hours at over $100 you follow procedure. For TVs, especially bigscreens, there is a procedure. This procedure is actually not completely in compliance with Ohio law, but it must be done.
The first and foremost goal is to see a picture. Period. That is the first thing you do, that tells you if the tubes are good, if there's any screen burn, and the trained eye can see other problems.
Now you can do what I said earlier, sub the drive but watch the voltage, but on a 195 that isn't worth shit.
Now you say it is blowing when in standby, that tells me that it is overvoltage most likely, or something open in the snubber network, which IIRC isn't much in a 195.
At $100 an hour, I'll tell you what the problem is, because David did not get pissed. You have a shorted 130V (or whatever) rectifier. It is on the secondary side of the SMPS transformer. That would be the first thing I check when I see a 195 burn down. (that's what I call it when the chopper fries out)
Whatever switching device they use on the primary side I call the chopper. I have simplified my thinking. The situation with the 195 chassis is this; It does have short circuit protection. How many times did you hear one chirp and throw in a 2SC5148 and a 239111 and have the set work ?
Well I found out why. That circuit can handle a dead short on the output, if the highspeed rectifier is not shorted. Don't know exactly why, but a shorted load to a good power supply can be tolerated, but when there is a shorted rectifier it can't do it. This affects the feedback in a way that the circuitry cannot handle. When that main 130 V or whatever rectifier is good and the set is running you can almost take and short the HOT E to C and it will simply start working again when the short is removed. But the shorted rectifier shunts the transformer winding in a way the shorted load can not. See what I mean ?
In other words, if the high source (the one that feeds the fly) is shorted it is still getting negative pulses feedback. I haven't really studied the circuit enough to fix it or say exactly why, but I know it is a fact. Like some other sets, ir may just be unable to oscillate at all and winds up with class A bias. Don't think that just because there is a heatsink that it would not blow immediately either, there is a thermal resistance of the die to the case. When you put DC bias on a transistor with 160V C to E it can burn up so fast the case doesn't even get hot, and neither does the heatsink. Really, I don't know if this is the exact failure mode, but I don't care. Get the job done.
Dude, I have not known David to ever put someone down, and that accusation is probably your perception. If he told you not to mess with a 195 without training or at least the manual and alot of experience in the field, he was right. Even the 195 print sucks. Then there are all these specifics you need to know. Wait until you get a problem in the signal circuit of a 195, or better yet, you see a CTC211.
If David (and others) on this board told me to get out of something, I would very much consider their advice. Sometimes there a so many specifics you need you just can't do it. Even with a print. Not having read the training manual is a BIG BIG handicap. Now this is coming from a guy who has almost 30 years experience, makes twice as much an hour as anyone in the shop (over $20) and gets perks that you wouldn't believe. I know my shit, but I also know my limitations.
But the 195 is not beyond that. Now, if you are reading a shorted HOT in circuit, test the thing out of circuit. I bet it ain't shorted, that is because you are reading the diode that feeds the fly, (that IS a coil of wire to ground) Read the pad and I bet it is still shorted, but the transistor ain't.
I give it an 85% chance right. Thats another thing about top techs, the owner or purchasing agent must tell the tech the price of the parts for those times when you just can't tell, it is either this or that, and I can't tell which. Then you learn. Sometimes it is the cheap readily available part, other times not.
In any case, DO NOT use an ECG type replacement there, use at least a
243636, which I think is an MI-35. ECG probably still says the 580 or whatever can replace it, but they are full of shit. It is not fast enough. If you have any real 164589s on the shelf they will work fine too.
Now that's the kind of shit we get paid for.I don't mean to go on forever about this, but suffice it to say, we DO earn our money.
JURB