Help with a (generic?) H-12 Universal Chassis

[kyle__]

I'm trying to use a somewhat generic universal chassis labeled, "H-12" on the board, and "EPSP648" in some places in the listing I bought it on. I can't find much information about it.  The tube I'm using is labeled WG 1220872.  It came to me in an otherwise empty cabinet.  No boards/chassis etc, but was told it worked.

Anyway, I can't find docs on this exact board, but from reading various sources, I thought I had things hooked up right.  However, whenever I power it on, it pops the circuit.  I am not using an isolating transformer but thought I read newer chassis didn't need that.

When I measure the windings, I get 2.3 and 5.6 ohms.

If there are other pictures or measurements needed, I'd be happy to provide.

[kyle__]

It didn't like so many pictures in one post.
Neck board.  The other two pictures I took probably aren't that useful (model label on the tube & screen printing of the board name on the chassis).

[grantspain]

are you running the chassis from a iso transformer?

[PL1]

are you running the chassis from a iso transformer?

I am not using an isolating transformer but thought I read newer chassis didn't need that.

Scott

[Ken Layton]

That chassis REQUIRES operation from an isolation transformer.

[kyle__]

Oh.  OK.  So, is that something you can tell from looking at it, or the model?   How does one figure that out?

Edit, also ordered this from Jameco: https://www.jameco.com/z/ITR300-Power-Transformer-Isolation-120VAC-120VAC-300VA_181315.html

[Ken Layton]

I can tell by looking at the chassis. There would have been a large yellow transformer in the power supply section. That would have been part of a switching regulator power supply. Since it didn't have that transformer, this is a chassis that needs an isolation transformer.

By the way the transformer you ordered is a bit overkill for the common monitors. Here is what most games requiring isolation use:

http://www.arcadeshop.com/i/1346/monitor-isolation-transformer.htm

[kyle__]

So .... if I plug in the chassis to the isolation transformer, and plug it in, it blows the fuse on the transformer.  Did my plugging this in without an iso transofrmer kill it; is it a lemon of a board; or do I just have it hooked up backassward?

[grantspain]

check the diodes in the bridge circuit and the regulator

[kyle__]

I tested all the diodes I could identify.  They seem fine.

I don't know if it's related to what's happening, but what are these circled in white here?
The short wires jumpered to one of two pins.

[kyle__]

Well, I decided to try yet another new chassis, and it lives!

So either my naive rough handling killed that first chassis, or it was a lemon.    As a bonus, this one had a degaussing coil and one page (duplexed) of documentation.    It's not perfect, but it works enough for my proposes. 

Before I bundle this into the cabinet again, what is this E pin for?

[grantspain]

crt earth, its the single wire that comes from the dag earth that surrounds the back of the crt( the metal braid)
absolutely critical