Set voltages for Scott Sixteen

[Joe Miller]

I am working on a Sixteen that plays but suddenly lost volume.  I see that it has been nicely recapped except for the wax caps that are hard to get at under the coils.  (not sure I can get to them myself).  Anyway, I will be swapping tubes and then checking voltages if I can find them.  I didn't see voltages in the document on the EH Google site.  Anyone know where I can find them.

Thanks,

Joe Miller

[Norman S Braithwaite]

Voltages are identified next to the B+ and C- divider resistors on the schematic.  Voltages at plates and screen grids should be relatively close to the divider voltages.

Norman

[Joe Miller]

Thanks Norm, now I see them.  I didn't notice them given the poor legibility of the schematic I have.

Is there a better source for this schematic that might be more legible?

Joe

[David C. Poland]

Riders diagrams are clear, if you have access to a set.   Volume 14  .

Nostalgic Air consists of photocopies of Riders and are often clear enough. http://www.nostalgiaair.org

[Kent King]

If we have items that are badly scanned, I'll try to redo them as I can. I'll make a note on the Sixteen. 

[Joe Miller]

I have an open IF diode coil in the plate circuit of the 3rd IF tube. Will take it apart on Saturday to see if if is the winding or the 1k resistor inside. Planning ahead:
1. Is the if diode coil unobtanium? (In case I can't fix mine)
2. Anyone have a more clear procedure for doing the if alignment? The one in the service manual isn't very clear regarding the placement of jumpers and other c objections.
Joe

[Kent King]

Joe -

If the coil is open, I've got some graveyard sets I'd have to check, but I suspect I can provide the coil. When you remove the diode, replace that paper/wax capacitor that feeds through the body, it can short and burn out the 1K resistor. Lots of restorers don't replace the diode cap, but it isn't that hard to do, I replace all of them during my restorations.

Kent

[Norman S Braithwaite]

Joe:

IF alignment for the Sixteen is more straightforward than it sounds from the manual.  Scott provided terminals for the jumpers at the bottom of the IF cans for the purpose.  I have found the procedure identified by EH Scott Radio Laboratories for the Sixteen to produce noticeably better performance than a conventional alignment without use of the jumpers.

Norman

[Joe Miller]

Great news, the coil is good, the 1000 ohm resistor is open. So I should be able to move forward. Given the coil is good I may not have to do an IF alignment after all. I am troubleshooting this set for a friend (Y2kBruce) and none of the work you see was done by me. I found about a dozen caps that were not replaced due to their location, nearly impossible to get at some of them.

Norman, I was having trouble trying to figure out which jumpers to use for an IF alignment. See picture. I think someone may have done some major surgery on this set. Looks like the terminals for jumpering during alignment of IF have been removed.
Joe

[Joe Miller]

Kent,

I will send you the serial number on this set when I get back to it.  You may already have it because it belongs to Bruce.

Joe

[Kent King]

Joe -

You are right, that set has had some surgery, it doesn't look like a typical Sixteen. I'll bet you won't have too many issues once you fix the diode. Good luck and let us know how it comes out.

Kent

[Norman S Braithwaite]

Bummer!  Someone did make it harder to align per the instructions of EH Scott Radio Laboratories.

Norman

Joe Miller said:

Great news, the coil is good, the 1000 ohm resistor is open. So I should be able to move forward. Given the coil is good I may not have to do an IF alignment after all. I am troubleshooting this set for a friend (Y2kBruce) and none of the work you see was done by me. I found about a dozen caps that were not replaced due to their location, nearly impossible to get at some of them.

Norman, I was having trouble trying to figure out which jumpers to use for an IF alignment. See picture. I think someone may have done some major surgery on this set. Looks like the terminals for jumpering during alignment of IF have been removed.
Joe

[Joe Miller]

Back in business.  Replaced the 1000 ohm resistor in the IF diode and all is good.  Also replaced the cap while I was in there.  Not sure why the resistor burned out because the cap was not shorted.  I assume it must leak by when B+ voltage was applied.  Thanks for your help, gents.

Kent, the serial on this set (Bruce's) is JJ-218.

Joe