Fuse F850 and F852 are open. They are part of the 16 volt and 32 volt supplies that are used by the convergence board. I still have not removed the power/def board but will need to. I believe the 32 volt supply is developed with a doubler circuit and both fuses being blown in the same area indicate the problem may be the supply components themselves. Capacitors, bridge or single rectifiers for example. Does anyone have any experience with this particular problem? Still haven't figured out how to disconnect the blue connector which connects the two circuit boards. The white connectors (2) disconnect and I assume the blue must have a similar mechanism.
Where exactly are the fuses? I am having the power light blinking problem all of a sudden. About a year ago I replaced the convergence ICs. The first fuse I see is the F850, and it is right behind where the power plug is attached to the power board. No problem with that fuse that I can see. I am gathering there are other fuses. It sounds like they may be around the convergence board. Any help in locating these fuses for inspection would be greatly appreciated.
Theres two jumper wires around the convergence ic's that supply the +/-32 volts to them.I found a cold solder joint on one of them.This causes the fuses to blow.Their close to the edge where the two boards meet.
There are 8 pico fuses on the power board.Most are black and 1or 2 green.Look for a green one at the front center of the power board.They all begin with "f".The convergence ic,s are on the (SSB)small signal board.Check for bad connection around convergence ic,s and replace bad fuses.If set is still dead unsolder convergence ic,s (completely).Turn set on for 4 or 5 seconds, if it comes on replace ic,s with higher watt ic,s 392-110 are 110 watts try 150 watts.Also try unsoldering audio ic.
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If the convergence power supply fuses blew you can bet that the convergence ICs need to be changed. The blue connector will be pressed down on the rear of the connector to release or pulled up on the back end of the socket. Ps dont forget to rate this.
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OK Thanks for your input Techman. Where can I get the parts to fix the set? I have one location in Ohio Fox Electronics I think. Can you identify the IC's that usually blow on the convergence board? TIA for any help you can provide.
I was able to pop the connectors open (2 white and 1 blue) with a small screwdriver. Removing the power/def board was necessary to replace the fuses properly. If the convergence board is the one to the right of the power/def board I'll need to remove it too.
Techman,
I see the two IC's on the board with the large heat sinks on them.
Do you know from experience that the IC's blow? They look tough to get at as they are blocked by a tuner vertically mounted on the PCB. I see the IC's use the +32 volts that had a fuse blown but not the +16 volt which also had a fuse blown. There could have been a load an the 16 volts too. I hate to change the fuses and IC's without knowing I've fixed the problem. What info. can you give me? I'm assuming these are the convergence IC's your solution mentioned. I located them by tracing the +32 volt line.
TIA,
C5Z06
I mentioned this in another post and that was my problem too. This is normally a $400 repair charge.
Thanks,
C5Z06
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