Meet "Val" PL 400 series 1, SN 171xx

[mlucitt]

I'll get back to you, have to look that up. It's a 2 pole 3 position, make before break switch. Got them from a surplus electronics company in Florida.

The rotary switches are more Phase Linearly than a toggle switch. I'm in Florida, so maybe close...

 

[Oldskoolfan]

Found it! West Florida Components, but you better hurry if you want one. They only have 2509 in stock . Rotary Switch 2 Pole 3 Position | West Florida Components

 

[mlucitt]

Found it! West Florida Components, but you better hurry if you want one. They only have 2509 in stock . Rotary Switch 2 Pole 3 Position | West Florida Components

Thanks, I'd like to buy them all and make them available to the upgraders. But I think I will just buy ten for now...

 

[Oldskoolfan]

Finished the control board this afternoon. Next step is to route the wiring for the volume controls and meters. Then complete the chassis harness, perform board installs and connections.
Gotta build a DBT yet. Considering a cheap variac since I have another 400 to rebuild. Hope I don't let the magic smoke out when I fire it up.

 

[gene french]

Finished the control board this afternoon. Next step is to route the wiring for the volume controls and meters. Then complete the chassis harness, perform board installs and connections.
Gotta build a DBT yet. Considering a cheap variac since I have another 400 to rebuild. Hope I don't let the magic smoke out when I fire it up. View attachment 76247 View attachment 76248

looks very nice...

 

[AngrySailor]

Finished the control board this afternoon. Next step is to route the wiring for the volume controls and meters. Then complete the chassis harness, perform board installs and connections.
Gotta build a DBT yet. Considering a cheap variac since I have another 400 to rebuild. Hope I don't let the magic smoke out when I fire it up. View attachment 76247 View attachment 76248

I got a cheap variac off crapazon, it’s definitely made of pure chinesium, the meter which I wouldn’t trust anyways crapped out first use, but it does do the job I guess... can’t complain for the $80 or whatever it cost really.

 

[Oldskoolfan]

I got a cheap variac off crapazon, it’s definitely made of pure chinesium, the meter which I wouldn’t trust anyways crapped out first use, but it does do the job I guess... can’t complain for the $80 or whatever it cost really.

Those are the ones I've been looking at. Don't really care about the meter, I got 2 flukes.

 

[George S.]

I suggest the simplest DBT is best. If you want meters use your Fluke. Switches on a DBT are unnecessary and they can complicate that critical time. Once it passes "bringing it up", your done with the DBT anyway.
Short 3 wire extension cord, carefully remove outer insulation at midpoint. Cut the black Line wire and connect it to your lamp base. Done. Weighs nothing and stows on the shelf easily.

 

[Oldskoolfan]

Almost ready for power up and testing. Waiting on a heatsink for the triac. Not because it needs it, but for insurance to keep the legs up off the chassis.

 

[Oldskoolfan]

Sunday's work. BTW, any reason the DBT has to have a 100 watt bulb?

 

[gene french]

bigger the bulb...more amps are passed...100w bulb is a bit less than 1 amp...

 

[Gepetto]

Sunday's work. BTW, any reason the DBT has to have a 100 watt bulb? View attachment 76388

You will be better off using shielded twisted pair for the pot connections...

 

[Oldskoolfan]

bigger the bulb...more amps are passed...100w bulb is a bit less than 1 amp...

Then a 75 watt bulb should be good because if there is a short in the amp, current would be limited to less than an amp. Correct?

 

[Oldskoolfan]

You will be better off using shielded twisted pair for the pot connections...

Would you float the shield or ground to the chassis? I went this route because the coax center conductor just wasn't substantial enough to take any stress if moved much.

 

[Gepetto]

Would you float the shield or ground to the chassis? I went this route because the coax center conductor just wasn't substantial enough to take any stress if moved much.

Shielded twisted pair, 22AWG conductors. Look up UL 2547 style cable. It is available in 22AWG shielded. Available from many sources, very common.

 

[gene french]

Then a 75 watt bulb should be good because if there is a short in the amp, current would be limited to less than an amp. Correct?

100w bulb will pass .833 amps..
75w bulb will pass .625 amps...
at 120v...

 

[Oldskoolfan]

100w bulb will pass .833 amps..
75w bulb will pass .625 amps...
at 120v...

75 watt bulb works like a champ. Built my DBT this afternoon. Tried it on a known good amp. Acts like a soft start circuit.

 

[laatsch55]

In fact. A DBT will literally piss off a soft start circuit..

 

[mlucitt]

Shielded twisted pair, 22AWG conductors. Look up UL 2547 style cable. It is available in 22AWG shielded. Available from many sources, very common.

Is the Chinese cable any good? ebay had 62 results, all from China...
I would prefer USA cable. Maybe Belden 8761?

 

[WOPL Sniffer]

Navo carries all the good stuff. Why deal with China OR Ebay???