EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Dave McClellan
  • Male
  • Dandridge, Tennessee
  • United States
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Dave McClellan's Discussions

SCOTT 16 6K7 FIRST AUDIO AMPLIFIER CIRCUIT QUESTION

Started this discussion. Last reply by Dave McClellan Jun 15. 2 Replies

The schematics I have (Steve Johnson and Riders) shows that the 6K7 cathode is grounded and the bias is supplied through a 1meg resistor from the -10 volt bias divider resistor string. My radio is…Continue

SCOTT 16 HUM PROBLEM

Started this discussion. Last reply by Alex R. Whitaker Jun 13. 6 Replies

I started a new thread for this problem since a previous thread *SCOTT 16 CAPACITOR QUESTION" had drifted off of the original question, which was answered. The radio works, but there is a strong 60hZ…Continue

Scott 16 Capacitor Question

Started this discussion. Last reply by Dave McClellan Jun 12. 12 Replies

I have a model 16 on the bench for checkout. The current owner has never powered it up and asked me to check it out. It has been electrically restored in the 1985 time frame. The replacement…Continue

 

Dave McClellan's Page

Latest Activity

George liked Dave McClellan's discussion SCOTT 16 6K7 FIRST AUDIO AMPLIFIER CIRCUIT QUESTION
Aug 28
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"I received my selection of O-rings from Grainger today. I first tried ONE 1/16 x 2 5/8". It stayed on the pulleys but slipped. So I added a two more. They are actually about 0.068" in diameter, so three is close to 1/4". These stay on…"
Jun 21
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"Will it work without a belt tensioner? Mine has been removed. If so, yes. "
Jun 21
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"I did add shims to the bracket holding the tuning shaft pulley using my stock of thin brass of various thicknesses. I could tilt the pully either up or down a small amount. It made no difference, except which side of the pulley the belt climbed. The…"
Jun 20
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"There is a slight amount of play (wiggle) in both pulleys. It is difficult to determine if the two shafts are parallel by eye. The two plates are definitely firmly attached by the 4 studs so no relative movement of the plates should occur. "
Jun 19
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"Are the GC belts mentioned new cloth or rubber? The belt tensioner appears to have been removed in my radio, so Zenith type cloth belts cannot be used. I tried trimming the width of the 8.6" Elliot Electronics belt (quite difficult) but there…"
Jun 19
Dave McClellan replied to Robert Feenstra's discussion New member - Scott 16
"I ordered and tried both the 8.8 and 8.6 and neither work. In both cases, the belt climbs up one or both pulleys and will not stay in the groove. I cut and spliced an O-ring that is about 2.5" inner diameter. It works, but is kind of stiff,…"
Jun 18
Dave McClellan replied to Dave McClellan's discussion SCOTT 16 6K7 FIRST AUDIO AMPLIFIER CIRCUIT QUESTION
"The connections are definitely NOT original. After further reading on the Forum, hum originating in the 6K7 1st AF amp stage was discussed. In the original circuit, the 6K7 grid bias comes a tap on the bias divider resistor string, sourced from the…"
Jun 15
Kent King replied to Dave McClellan's discussion SCOTT 16 6K7 FIRST AUDIO AMPLIFIER CIRCUIT QUESTION
"The Sixteen was a fairly short-lived model that did not see much in the way of change. Since you noted the resistor was a 5%, I'm guessing (without pics) this may be a more modern replacement. Do the solder joints look "original"? If…"
Jun 15
Dave McClellan posted a discussion

SCOTT 16 6K7 FIRST AUDIO AMPLIFIER CIRCUIT QUESTION

The schematics I have (Steve Johnson and Riders) shows that the 6K7 cathode is grounded and the bias is supplied through a 1meg resistor from the -10 volt bias divider resistor string. My radio is quite different: the 6K7 cathode (and suppressor) go through an unbypassed 680 ohm resistor to ground, and the 1meg grid resistor is grounded. The resistor (5%) does not look original.In addition, in my radio the 6K7 first audio amp gets its screen supply through a 100K resistor. The schematics say…See More
Jun 14
Alex R. Whitaker replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"Yep, a dial light or heater string full short can get "interesting" really quickly!"
Jun 13
Norman S Braithwaite replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"Dave, you are not the first to encounter the dial light short problem!  At least in my case it was a full short and quickly found. Norman"
Jun 13
Dave McClellan replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"Well, I made a rookie mistake. I apologize to the Forum for wasting your time. When I removed the tuner shield to inspect for any original capacitors left (there was one), the shield pinched a pilot lamp lead when reinstalled. In this radio, the…"
Jun 13
David C. Poland replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"There should be 5K resistor between the top of the voltage divider and the inverter plate. Also poke around the bass resonator circuit ahead of the inverter. Anyone?"
Jun 12
Dave McClellan replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"Thanks for your response. Some hum problems trace back to the 1st audio in some models, including the 6K7-G in the Sixteen. The hum is there with the 6K7 removed, or its output disconnected from the inverter, or even if the inverter grid is…"
Jun 12
David C. Poland replied to Dave McClellan's discussion SCOTT 16 HUM PROBLEM
"Some hum problems trace back to the 1st audio in some models, including the 6K7-G in the Sixteen. Illusive hum problems are a trial for sure. The low 60 cycle ac appears only at the inverter plate and no other tube plates? Cathode to filament leak…"
Jun 12

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