[QuadList] Ampex VR2000A

[Pat Shevlin]

Guys,

 

I am restoring an Ampex VR2000A quad VTR.  I now have E-E signal through the
machine.

 

In the Play mode I only have noise coming out of the demod.

 

I checked the head assembly modules in back of the machine and found no RF
going into the head amps.

 

I know this machine has nuvistors and 6761 tubes so 6.2vac filament voltage
is required.  I measured the output of the filament transformer and I only
have 1.3vac in E-E mode and play mode.  Measuring the input of the
transformer I have approx 118vac.  (see attached pictures)

 

I replaced the filament transformer and have only 1.3vac.  I also replaced
K1 located just above the filament transformer, no difference still got
1.3vac.

 

I do not have a schematic diagram of the transformer or what is controlling
K1.  I do not know if any what role K1 plays in triggering 6.2vac filament
voltage.  There is a large cap (C1) located next to K1.  (see picture below)
I have no idea what role that plays either.

 

There are 4 wires on the primary side of the filament transformer and two
wiring on the secondary that should output the 6.2vac.

 

Since I do not have a diagram, I do not understand the operation of
generating the 6.2vac filament voltage.  What control if any turns on the
6.2vac?

 

Any ideas what my problem may be?

 

Pat 

 


				
		 		 
	
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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