PL 700 Pro Build

[George S.]

Thanks Joe, thought about that, but I've got all winter to build this, so...... After dinner I'll check voltages for the other Cylon meter wires and get them soldered in. Then it's back to work for a week. Pretty happy with what I got done this weekend in between the family and everything else. Merry Christmas Joe. Thanks

 

[Gepetto]

Thanks Joe, thought about that, but I've got all winter to build this, so...... After dinner I'll check voltages for the other Cylon meter wires and get them soldered in. Then it's back to work for a week. Pretty happy with what I got done this weekend in between the family and everything else. Merry Christmas Joe. Thanks

Travel safe George. Merry Christmas!

 

[George S.]

I might have a problem.
Checking voltages on the solid yellow, orange, and gray(it was capped unused) wires coming out of the transformer with aim to power the 12 VAC WOAD Cylon meters connections AC1 and AC2.
Orange is 44 VAC, yellow is 35 VAC, grey 39 VAC. Meter is between the wire and the secondary center tap. A second backup meter shows same results.
Only the main fuse is in, no rail fuses, caps are connected.
Wondering if I need to assemble the amp further along and this will "pull down" those high AC voltages or if I have a different issue.
B- is -102 VDC, B+ is +102 VDC.
I feel I'm overlooking something simple. Just can't figure out what.

 

[Gepetto]

I might have a problem.
Checking voltages on the solid yellow, orange, and gray(it was capped unused) wires coming out of the transformer with aim to power the 12 VAC WOAD Cylon meters connections AC1 and AC2.
Orange is 44 VAC, yellow is 35 VAC, grey 39 VAC. Meter is between the wire and the secondary center tap. A second backup meter shows same results.
Only the main fuse is in, no rail fuses, caps are connected.
Wondering if I need to assemble the amp further along and this will "pull down" those high AC voltages or if I have a different issue.
B- is -102 VDC, B+ is +102 VDC.
I feel I'm overlooking something simple. Just can't figure out what.

That appears to be a problem George...proceed cautiously

 

[George S.]

That appears to be a problem George...proceed cautiously

Joe, I'm going to pull the transformer, closely inspect it, then bench check it "naked". Will update what I find. I should have done this first. Live and learn!

 

[George S.]

Question: if I need to replace this 700 Series 2 type transformer, does the original 700 or 700B transformer have two 12 VAC secondaries which would power the Cylon meters? Just considering options if need be. Thanks all.

 

[Gepetto]

Question: if I need to replace this 700 Series 2 type transformer, does the original 700 or 700B transformer have two 12 VAC secondaries which would power the Cylon meters? Just considering options if need be. Thanks all.

No, the 700B and earlier have a single 6VAC secondary.

 

[George S.]

No, the 700B and earlier have a single 6VAC secondary.

Thanks Joe.

 

[Gepetto]

I might have a problem.
Checking voltages on the solid yellow, orange, and gray(it was capped unused) wires coming out of the transformer with aim to power the 12 VAC WOAD Cylon meters connections AC1 and AC2.
Orange is 44 VAC, yellow is 35 VAC, grey 39 VAC. Meter is between the wire and the secondary center tap. A second backup meter shows same results.
Only the main fuse is in, no rail fuses, caps are connected.
Wondering if I need to assemble the amp further along and this will "pull down" those high AC voltages or if I have a different issue.
B- is -102 VDC, B+ is +102 VDC.
I feel I'm overlooking something simple. Just can't figure out what.

Hi George
What are you measuring these AC voltages with respect to? You give 3 different AC voltages with only one wire color cited?

 

[George S.]

Hi George
What are you measuring these AC voltages with respect to? You give 3 different AC voltages with only one wire color cited?

No, I give 3 colors and respective VAC. Solid orange 44, solid yellow 35, solid grey 39.
The trans also has the 2 solid red wires hooked to the rectifier exactly as the original rectifier, a single stranded black center tap, and the standard dual primary two pairs, one pair striped, one pair solid. Have good photos of original wiring at terminal strip and rectifier, will send once I get good cell service.

 

[Gepetto]

Hi George
Are you saying that you have 2 orange wires, 2 yellow wires and 2 gray wires exiting your transformer? Not likely.

 

[George S.]

No Joe, When measuring, meter is between given secondary wire a center tap. The issue is with the solid orange and solid yellow. Pulled the cap off the solid grey to also measure it.

 

[Gepetto]

There is no center tap on the secondary George. It is one winding.

No Joe, When measuring, meter is between given secondary wire a center tap. The issue is with the solid orange and solid yellow. Pulled the cap off the solid grey to also measure it.

See the 2 green stubs in your second picture, that is where you should measure the secondary AC across. In your first picture, you can see the small fine wire that acts as the fuse shown on the schematic between the 2 lugs.

 

[George S.]

There is no center tap on the secondary George. It is one winding.

See the 2 green stubs in your second picture, that is where you should measure the secondary AC across. In your first picture, you can see the small fine wire that acts as the fuse shown on the schematic between the 2 lugs.

Will do!!!!

 

[Skratch]

across Orange and yellow should be 12 vac

 

[George S.]

Should, but was getting about 2 VAC across Yellow and Orange. Little while later I replaced all batteries in the Fluke and Radio Shack True RMS meters. Was still getting bad results so pulled out a old Micronta, put in fresh batteries, and started checking line voltage with all three. Found the Radio Shack TRMS was way off on VAC. The Fluke was always the best, so retested and couldn't get 12 VAC in any configuration. Even swapped out leads.
Will try again this weekend. Thanks everyone!

 

[Skratch]

You've got a Gremlin somewhere

 

[Gepetto]

You've got a Gremlin somewhere

 

[Skratch]

View attachment 58894

I might have built that when I worked at American Motors in Kenosha in the early 70's

 

[Skratch]

No Joe, When measuring, meter is between given secondary wire a center tap. The issue is with the solid orange and solid yellow. Pulled the cap off the solid grey to also measure it.

The 2 small green wires go to the LED board and your DC voltage is correct so your primary is wired correctly