All things LA2a related

[wave]

OK if I lift the green/yellow&red/yellow from the ground point on the tag strip the mains fuse doesnt blow and i get about 360VDC at A22/A23
and 85VAC at A24/A25 as soon as I reconnect the center taps to ground the fuse goes when the power switch is thrown

 

[wave]

By tag 2 I meant where the big 'lytics are the middle 3 tags are wired together and into the ground bus so instead of wiring center taps to the middle tag I wired it to the second from the bottom tag

 

[wave]

I've lifted the green wires and the center taps. I get continuity when probing a green and the green/yellow but not when probing a red and the red/yellow is that right?
I'm also testing on a correctly wired outlet now

 

[wave]

Alright I'm at a loss...
I rechecked all my wiring at the power supply and I cant' figure out why the fuse blows only when the secondary center taps are connected to ground.
I need some serious help...starting to get depressed

 

[Scenaria]

when you say continuity are you using the one that beeps on your meter?

instead measure resistance...

measure the red to red

and then from one red to the stripped red

and the other red to the stripped red

you should get approx 500ohms between the two red

and 250-275 ohms between the stripped red and each of the solid reds...


Patience! dont get depressed... if this stuff was easy then everyone would be doing it. These things take time...

 

[wave]

550 ohms red to red
267 ohms red1 to red/yellow
280 ohms red2 to red /yellow
.4 ohms green to green
.2 ohms green1 to green/yellow
.2 ohms green2 to green/yellow
thanks

 

[CJ]

Listen carefully:

First, read my signature at the bottom of this post.

Second:

Unplug the unit.

Short out your filter caps with your least favorite screwdriver to discharge them.

Disconnect all secondary high voltage ac wires coming out of the power transformer.
Including the center tap.

Clip the black lead of your ohm meter to the chassis at a good, non powder coated ground point.

Measure the resistance with the red ohm meter lead of the points where the secondary wires, which have now been dis connected, are supposed to be soldered to and report back immediately because I am getting old.

 

[Scenaria]

getting old? or are old?

:green:

:guinness: :guinness: :guinness: :guinness:

 

[wave]

I'm getting nothing (OL) on the meter

 

[CJ]

Keef told me you were on the blue pill.

 

[Scenaria]

what the hell is the blue pill? a matrix thing?

scrape some powder coat off the points where you are grounding to chassis... also be sure to dig your probe into the metal a little.. when checking..

 

[CJ]

I told him that already, punk!

OK. Nothing is good.

Now measure the resistance on the other side of the diodes.
Your meter should gradually rise in resistance as the filters charge.

 

[Scenaria]

I bet he didnt dig the probe into the metal deep enough

cj... you need to come down to FL and hit the hookah pipe one of these days... :green:

where the two tag boards are screwed onto the chassis... be sure that the screws are making good contact with the chassis metal.. not the powder coat. thats why theres star washers... to help dig through the paint

 

[CJ]

Blue pill=Viagra.

Steve, is he using this layout:

http://www.vacuumbrain.com/The_Lab/TA/LA2/la2a_layout2.jpg

 

[wave]

OK
I really scraped off some powdercoat, put on the clip, measured to the IEC ground got .3 ohms so the clip is on good
Measured the turrets where the secondaries were soldered.. I get no reading (OL) on the meter. That means no shorts to chassis right?

 

[wave]

I've been religiously checking against that layout (rev 5-15-05 ) the whole build (printed a tabloid size) as it's much easier for me to understand than a schematic

 

[Scenaria]

[quote author="CJ"]Blue pill=Viagra.

Steve, is he using this layout:

http://www.vacuumbrain.com/The_Lab/TA/LA2/la2a_layout2.jpg[/quote]

more than likely... guess we should ask wave

wave: are you using the above layout?

I dont send that layout with the kits as its rons and not mine to use.. rather the manual steps them one connection at a time..

the manual does follow that layout though.. so its good reference

 

[CJ]

Yes, no shorts to chassis.
Now get on the junction of those 1N4... "whatever they are" diodes and measure ohms.

 

[Scenaria]

4007's

:grin:

 

[CJ]

Dammit Steve! We only have 40 pages left!