Pioneer PL-740 Turntable

[poppachubby]

Once again Stan, my suggestion is to check the fuses in the unit. Anytime I get a "new" vintage amp, I replace all the fuses/lamps while giving it a cleaning. I don't think your problem is connectivity. Don't bother with the MC function, you need MM. In fact, it's funny that your unit has MC. I guess they put it there so an audiphile has something to plug into, for the week or two it'll take to upgrade ASAP. I'll look at the schematic as soon as I have some time Stan, in the mean time post your results from noobs test.

[manlystanley]

Once again Stan, my suggestion is to check the fuses in the unit. Anytime I get a "new" vintage amp, I replace all the fuses/lamps while giving it a cleaning. I don't think your problem is connectivity. Don't bother with the MC function, you need MM. In fact, it's funny that your unit has MC. I guess they put it there so an audiphile has something to plug into, for the week or two it'll take to upgrade ASAP. I'll look at the schematic as soon as I have some time Stan, in the mean time post your results from noobs test.

Hello Chubbs,
I took it apart this week end again and really cleaned out everything. As you thought, it didn't do anything to help to clean the the phono switches and controls. But, what it did do is:

--> The base/treble/bass boost never worked. When ever I'd put the H/K into anything but tone default mode, it sounded garbled. But now, that section seems to work.

--> The balance was sounding scratchy I moved the potentiometer (though the speakers). But now, I can barley hear it.

--> And the *BIG* news. When I hooked it back up, the right speaker was dead. This has been a recurring problem that I've had. Sometimes its dead, other times it's lower power. But, what I did was to flip a few times the 'pre-out' button (that separates the pre and power amp portions). Well, just doing that a few times fixed it! So, I know what to do now when I get this problem back.

****--> So what I've learned is that on these old amps you need to clean the switches and pots multiple times. Then eventually, they will connect.

I'll keep working on it. I'll try out your fuses suggestion. The turntable works, because it does produce sound through the 'tuner input'. Oh I wish I had an oscilloscope..... I've got the units schematics and so could follow the signals through the system and then find out where it's bad...

I'll try the fuses and get back to you.

Best Regards,
Stan