Pioneer SX-34B

[ocknroll]

Hi Everyone,
I'm new to this Group and hoping I can get some Guidance re my Amp ..
It's a Pioneer SX-34B ..Loud hum even with Vol turned down .. splashed all the Electro's with another one .. no Difference .. But while doing this I found no Voltage on one of the Electro's .. its connected to pin 7 of one of the 6EA8 valve via a resistor .. but no voltage there .. Looked at my diagram .. It dosent mention 6EA8 at all ( or equivalent ) ... so any help would be appreciated .. Cheers

 

[Soonerorlater]

Hi ocknroll, welcome to the forum.

My schematic calls for four 6BM8's, do you have four 6EA8's ?

 

[ocknroll]

Hi .. yes 4 x 6BM8's and 2X 6EA8's There is a coil next to the EA8's .. so could be something to do with Stereo FM .

 

[Soonerorlater]

The FM front end unit has no detail on my schematic but appears to have a heater supply to pins 4 and 5 which would suit the 6EA8's.

Any photos of the inside of your receiver ?

 

[Soonerorlater]

ok, looks like the mpx unit uses 2 x 6EA8's

 

[Soonerorlater]

As far as the hum is concerned I would first check the pair of 100uF electrolytic caps next to the mains transformer for "doming" of their tops. If so they should be replaced. If original I would replace them anyway.