Panasonioc RA-6500

JJayP

New Member
There is power to the transformer , switch, first (power board) but no lights or indication of anything else. my limited experience tells me thyristor.. It is an older model for sure so thyristor may not be what Im looking for.
Any ideas for my next step troubleshooting would be appreciated. JayP
 
Its hard to tell as there isn't a service manual or schematic readily available.
Check for AC voltage on the secondary windings of the transformer. If there is voltage, then look for seconday fuses on the board. When measuring for secondary ac voltage, make sure to measure across one of the windings. (like 2 red wires, or 2 blue, or 2 green etc)
This unit is pre thyristor, and probably uses transistor or hybred IC output.
These type of Panasonic units had a higher than normal failed power transformer issue. Many had internal fuses that would pop on overheat, or from a short. Some could be repaired, but some burnt the primary winding. Usually identifyable by the burnt spell at the holes where the wires exit.
Many of these panasonics also used dual full wave rectifiers for the power supply, (cathode/anode/cathode, and anode/cathode/anode). But that doesn't explain the lack of panel lights which is a seperate winding from the other power supplies.
Verify that the ac switch is good by checking for AC voltage across the contacts when it is powered on. You should get 0 volts.
 
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