8080DB no more sound after POP!

Hi guys, been blissfully listening to my 8080DB for the last several months after rebuilding the driver board. Tonight, all of a sudden I heard a POP and the receiver was in protection. Turned it off for a few minutes, turned it back on and it came out of protection, but no sound regardless of switch positions, speaker selection, AM/FM........... So I opened her up to look around for the usual sightings, fuses check OK, driver board checks out. Then I notice that the power supply board F-2619 looks pretty suspicious. C05 which appears to be protected in a vinyl tube is a nice shade of burnt and TR01 is a nice shade of crispy. It looks like it even melted the solder holding it to the board.

Anyways...Can someone recommend transistors and caps for this thing? If I can place an order with Digikey or Mouser in the next few days, I might be rockin' by Christmas time. Also, it looks like the board may be a little damaged under TR01, if someone might have a donor F-2619 let me know how much $$, just in case.

Now for the million dollar question, any idea what took this board out? I have run her hard for hours at a time with no problems before this. After rebuilding this board, what else should I look at so I don't have a repeat performance.

thanks

That Power supply board is for the Tuner and Dolby sections only. If you have the Dolby switch off you should be able to get sound from all the inputs except the tuner. If not check the 1 ohm resistors on the main power supply board they are probably toast. There are three of them.

Check your PMs

OK, R30 and R31 are open, R32 is 1ohm exactly. Should I simply replace them and be on my way or is ther something a little deeper I should also look at?

Of course I will still attempt to fix F-2619, I was listening to AM yesterday, so this must be recent.

Here is what happened, (most of the time) the power supply board failed, and caused the 1 ohm resistors to blow. If you disconnect the tuner cables from the unit (those near the selector switch) replace the 1 ohm resistors and you should be good to go for anything other than AM of FM or Dolby functions.


The tuner power supply board needs serious repair.

ON the F-2619 board, R01 and R02 are listed as 33ohm, 3-watt in the manual. I have 270ohm, 5-watt on my board. Does this sound right? Possibly a previous repair or did Sansui make a change?

The 270 ohm resistors are typically on that board. It's a Sansui factory substitution. They are wired in parallel giving an effective resistance of 135 ohms. CDfixer posted a modification to replace that pair with a single 200 ohm 20w resistor. It drops the voltage into the power supply and drops the temperature of the power transistor on that board.

- Pete

Here is a test that I want you to do, I am assuming you have a meter since you knew that the 1 ohm resistors were open. On the main power supply board there is a 3 watt resistor it is 10 ohms (on the 8080DB). Measure the voltage at the resistor. It should be about 55Volts.

Found the resistor, should I do this with the tuner in or out? Will I still get the voltage with R30 and R31 open?

Removed after you replace the 1 ohm resistors