Phonoland

Hello Forum,

I have just revamped the amplifier in my Seeburg 220. However, when I plug it in, I am not getting the right output on one of the test points (Pin #4 on J105). Pin #4 on J105 is supposed to be +365V, but I am basically reading 0V.

Pins #2 and #3 test ok at -22V and -35V, but Pin #4 is just not reading anything.

Any suggestions on what might be wrong or what I could try?

Thanks,
Michael

Michael, if this is a SHFA-1 check:

-Is the 5U4 lit?
-Is the fuse OK/
-Do you have voltage at pin 2 on the 5U4?
If so, check both ends of the choke.

Given that you just rebuilt it there is probably a connection missing or wrongly placed.

Schematics: http://www.verntisdale.com/Seeburgschem.htm

Rob

Rob-NYC wrote:Michael, if this is a SHFA-1 check:

-Is the 5U4 lit?
-Is the fuse OK/
-Do you have voltage at pin 2 on the 5U4?
If so, check both ends of the choke.

Given that you just rebuilt it there is probably a connection missing or wrongly placed.

Schematics: http://www.verntisdale.com/Seeburgschem.htm

Rob

Hello Rob,

Thank you for the feedback. That was really helpful.

The 5U4 is lit (at least at the top of the tube), but I am not getting any voltage off of Pin #2.

Is my transformer blown?

Best Regards,
Michael

Michael, is the speaker plug on the amp in? the center tap from the tran's HV secondary goes to ground through that connection. Check-jump. I usually just connect that directly to chassis ground to eliminate problems there.

There should be high AC voltage on pins 4&6 (5u4).. --Use extreme caution here, these are lethal voltages and current.---

Rob

Hello Rob,

Ah yes, I do not have the speaker plug in. I'm working on the selector box and amp at a separate location from the juke. I'll have to take them over and plug it in to see what happens.

Thanks again for all your help!

Best Regards,