|
|
|
|
|
#1
07-24-2015, 07:39 AM
|
|||
|
|||
|
Nope, looked everywhere. It seems the convergeance and deflection or whatever along with the flyback is all the same board. The two black STK chips and heat sinks are on the same large board lying down with the flyback. Board is labeled Conv/Def or something like that. Would a chassis number help? Is it possible for a fuse to be bad even if the element inside still seems intact? You would swear the fuse is blown on this because there is no power at all. Nothing.
|
|
#2
07-24-2015, 07:57 AM
|
|||
|
|||
|
Does anything look burnt? Pretty much out of ideas now. Were you able to check the PS board for ANY voltages? Not sure if its in shutdown or if the PS board has a problem. A schematic sure would be helpful. Fuses are probably OK if they look OK, but you can check them anyway.
|
|
#3
07-25-2015, 09:00 AM
|
|||
|
|||
|
Quote:
|
|
#4
07-25-2015, 09:08 AM
|
||||
|
||||
|
I STILL need some good pictures...of both of the large boards on the bottom of the set. The deflection board and the sigal board. I need to be able to see different connectors and such and i CAN then help you "figure it out. This has been my thing for many years....I weas out of the "scene" for a couple of years due to illnerss...but am getting "back in the saddle a little now.
|
|
#5
07-28-2015, 08:03 PM
|
|||
|
|||
|
Hope these help.
    
Last edited by pac.attack76; 07-28-2015 at 08:15 PM.
|
| Audiokarma |
|
#6
07-28-2015, 09:38 PM
|
||||
|
||||
|
They WILL work...GOOD pictures BTW.,..
You need to check that "whatcamacallit"..next to the "whatchmagieer" connected to the "thing a mig."!! Ok SERIOUSLY now... It looks as if you do NOT have a seperate standby power supply here ...so this means that the main SMPS runs at ALL times...or at least it is SUPPOSED to. I see a relay on the COLD side--this is likely to switch off the B+ to the Horiz ckt--in standby. Also what looks like an "SE" voltage reference chip" this is for regulation..it is in front of the relay--looks lke a TO-220 transistor. But in standby...it MAY not have voltage on it--if it is switched through that relay..but likely the relay is AFTER that reference chip. that large transformer is the SMPS power transformer. It powwrs the set. the VERY first thing you need to determine is...if it is even running at ALL. If you can...turn over the chassis and get a voltage reading on that large capacitor behind the SMPS tranny. You need to see if there is at least 150 volts DC on it..ACROSS it's terminals. If it DOES have that on it..(and since you say you see a spark when you plug the set in---it likely DOES)...then you need to see if you are getting ANY voltages out of the power supply. In front of the SMPS tranny...there are several capacitors with diodes near them. ALL of these diodes should have some sort of DC voltage on one side of them...as measured to chassis ground. LIkely 12 volts, maybe 24 volts, 18 volts and perhaps a 9 volt or 5 volt or so supply. A couple will likely shgow a negative voltage to ground--like -18 or maybe -24.. if you see voltages there....move over to the connectors that go over to the signal board (the green one on the left side of the power supply board)..and see how the voltages look on thaty connector. there MUST be at least a couple of voltages there in standby...a 12 volt or maybe a 5 volt supply. These power the MPU and remote ckts...to keep the set "alive". Ground the black probe and check and see what those connectors have on them. with the set off but plugged in...there likely will not be too many with voltages...but a FEW should have some voltages. Your convergence chips are up front on the deflection board..STK 394-250..and do NOT go bad as often as others but they CAN go bad. But it is NOT likely they will totally kill the set. They likely are powered by an +18 or +24 and - source--from the SMPS supply. Just for "kicks"..unplug those three 4 wire connectors in fornt of STK chips...those are the convergence lines...(be SURE to label them in some way...to get them back to the RIGHT connecors..otherwise...when you DO get the set to run...the convergence will be WAY off. ) So....check this out...and we will go from there !! Last edited by rca2000; 07-28-2015 at 10:02 PM. Reason: mistakes
|
|
#8
08-09-2015, 02:42 PM
|
||||
|
||||
|
Sorry--I have been busy for the last few days--with the 127 corridor sale and such.
ANYWAY...before you order ANY parts... what did you measure on the STR IC--to hot ground ? :Pins 1, 4 and 5...in particular. If 4 or 5 is off by much...that optocoupler is likiely loading things down.
|
|
#9
08-09-2015, 06:05 PM
|
|||
|
|||
|
Thanks Andy for the service manual. Very handy. I'm having trouble fiuring out which pins are which and if the board needs to be installed in the set when i test. Where is "hot ground"?
|
|
#10
08-09-2015, 06:38 PM
|
||||
|
||||
|
Hot ground is ther negative lead of that big capacitor you measured 171 volts on. This is the reference point for ALL voltages on that IC.
Looking at the IC from the front...see where the pins all go into it. From left to tight--pin 1 should be on the left and in order from there. I KNOW they are "staggered" in the way they end up on the PC board..But if you look at how they enter the IC--you should be able to figure out which pin is which. I tried to dowlaod that manual myself...but was NOT able to do so for some reason.
|
| Audiokarma |
|
#12
08-10-2015, 08:12 AM
|
|||
|
|||
|
Ok, guys, looking at the board where the words "live" and "isolated" read upright, the pins are like this:
. . . . . With the cap out to the left. Now, going from left to right, left to right, i got: -.033, -14.06, -.003, -1.26, .000 Not sure if i did this right. Red on right side of cap since the other side has a plus mark. Set to VDC.
|
 |
|
|
Hybrid Mode
